Schweitzer Engineering Laboratories SEL-751 User manual

20170927
*PM751-01-NB*
SEL-751 Relay
Feeder Protection Relay
Instruction Manual

SEL-751 Relay Instruction Manual Date Code 20170927
© 2011–2017 by Schweitzer Engineering Laboratories, Inc. All rights reserved.
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Schweitzer Engineering Laboratories, Inc. reserves all rights and benefits afforded under federal and international copyright and patent laws in its
products, including without limitation software, firmware, and documentation.
The information in this document is provided for informational use only and is subject to change without notice. Schweitzer Engineering
Laboratories, Inc. has approved only the English language document.
This product is covered by the standard SEL 10-year warranty. For warranty details, visit selinc.com or contact your customer service
representative. PM751-01

Date Code 20170927 Instruction Manual SEL-751 Relay
Table of Contents
R.Instruct ion Manual
List of Tables ........................................................................................................................................................ v
List of Figures...................................................................................................................................................xiii
Preface...............................................................................................................................................................xxiii
Manual Overview ..........................................................................................................................................xxiii
Safety Information.......................................................................................................................................... xxv
General Information ....................................................................................................................................xxviii
Section 1: Introduction and Specifications
Overview ......................................................................................................................................................... 1.1
Features............................................................................................................................................................ 1.1
Models, Options, and Accessories................................................................................................................... 1.5
Applications..................................................................................................................................................... 1.7
Getting Started................................................................................................................................................. 1.9
Specifications ................................................................................................................................................ 1.13
Section 2: Installation
Overview ......................................................................................................................................................... 2.1
Relay Placement .............................................................................................................................................. 2.1
I/O Configuration ............................................................................................................................................ 2.2
Relay Connections......................................................................................................................................... 2.19
AC/DC Control Connection Diagrams.......................................................................................................... 2.26
Arc-Flash Protection: System Installation..................................................................................................... 2.42
Field Serviceability........................................................................................................................................ 2.50
Section 3: PC Software
Overview ......................................................................................................................................................... 3.1
Setup................................................................................................................................................................ 3.2
Terminal........................................................................................................................................................... 3.3
Settings Database Management and Drivers ................................................................................................... 3.4
Settings ............................................................................................................................................................ 3.6
Event Analysis............................................................................................................................................... 3.11
Meter and Control.......................................................................................................................................... 3.13
ACSELERATOR QuickSet Help ...................................................................................................................... 3.18
Section 4: Protection and Logic Functions
Overview ......................................................................................................................................................... 4.1
Application Data.............................................................................................................................................. 4.3
Group Settings (SET Command)..................................................................................................................... 4.3
Logic Settings (SET L Command).............................................................................................................. 4.158
Global Settings (SET G Command)............................................................................................................ 4.169
Port Settings (SET P Command)................................................................................................................. 4.188
Front-Panel Settings (SET F Command)..................................................................................................... 4.193
Report Settings (SET R Command) ............................................................................................................ 4.205
DNP Map Settings (Set DNP n Command, n = 1, 2, or 3) ............................................................................. 4.208
Modbus Map Settings (SET M Command)................................................................................................. 4.209
Touchscreen Settings................................................................................................................................... 4.209

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Table of Contents
Section 5: Metering and Monitoring
Overview ......................................................................................................................................................... 5.1
Power Measurement Conventions ................................................................................................................... 5.2
Metering .......................................................................................................................................................... 5.2
Load Profiling................................................................................................................................................ 5.14
Station DC Battery Monitor .......................................................................................................................... 5.15
Breaker Monitor ............................................................................................................................................ 5.19
Section 6: Settings
Overview ......................................................................................................................................................... 6.1
View/Change Settings With the Two-Line Front Panel ................................................................................................ 6.2
View/Change Settings With the Touchscreen Front Panel................................................................................................. 6.4
View/Change Settings Over Communications Port......................................................................................... 6.4
Setting Entry Error Messages.......................................................................................................................... 6.6
SEL-751 Settings Sheets
Section 7: Communications
Overview ......................................................................................................................................................... 7.1
Communications Interfaces............................................................................................................................. 7.1
Communications Protocols............................................................................................................................ 7.11
Section 8: Front-Panel Operations
Overview ......................................................................................................................................................... 8.1
Two-Line Display Front Panel......................................................................................................................... 8.2
Touchscreen Display Front Panel .................................................................................................................. 8.18
Section 9: Bay Control
Overview ......................................................................................................................................................... 9.1
Bay Control Application Example ................................................................................................................ 9.13
Section 10: Analyzing Events
Overview ....................................................................................................................................................... 10.1
Event Reporting............................................................................................................................................. 10.2
High-Impedance Fault (HIF) Event Reporting............................................................................................ 10.29
Sequential Events Recorder (SER) Report.................................................................................................. 10.37
Section 11: Testing and Troubleshooting
Overview ....................................................................................................................................................... 11.1
Testing Tools.................................................................................................................................................. 11.1
Commissioning Tests..................................................................................................................................... 11.3
Periodic Tests (Routine Maintenance)......................................................................................................... 11.12
Self-Test....................................................................................................................................................... 11.13
Troubleshooting........................................................................................................................................... 11.16
Factory Assistance....................................................................................................................................... 11.17
Appendix A: Firmware, ICD, and Manual Versions
Firmware......................................................................................................................................................... A.1
ICD File.......................................................................................................................................................... A.8
Instruction Manual........................................................................................................................................ A.13
Appendix B: Firmware Upgrade Instructions
Overview .........................................................................................................................................................B.1
Upgrade Firmware Using QuickSet ................................................................................................................B.2
Upgrade Firmware Using a Terminal Emulator ..............................................................................................B.6
Protocol Verification for Relays With IEC 61850 Option..................................................................................................B.8
Factory Assistance...........................................................................................................................................B.9

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Date Code 20170927 Instruction Manual SEL-751 Relay
Table of Contents
Appendix C: SEL Communications Processors
SEL Communications Protocols......................................................................................................................C.1
SEL Communications Processor .....................................................................................................................C.3
SEL Communications Processor and Relay Architecture.....................................................................................C.5
SEL Communications Processor Example......................................................................................................C.7
Appendix D: DNP3 Communications
Overview ........................................................................................................................................................ D.1
Introduction to DNP3 ..................................................................................................................................... D.1
DNP3 in the SEL-751..................................................................................................................................... D.6
DNP3 Documentation .................................................................................................................................. D.14
Appendix E: Modbus RTU Communications
Overview .........................................................................................................................................................E.1
Communications Protocol ...............................................................................................................................E.2
Modbus Register Map ...................................................................................................................................E.25
Appendix F: IEC 61850 Communications
Features............................................................................................................................................................ F.1
Introduction to IEC 61850............................................................................................................................... F.2
IEC 61850 Operation....................................................................................................................................... F.3
IEC 61850 Configuration .............................................................................................................................. F.11
Logical Node Extensions............................................................................................................................... F.13
Logical Nodes................................................................................................................................................ F.19
Protocol Implementation Conformance Statement ....................................................................................... F.42
ACSI Conformance Statements..................................................................................................................... F.48
Appendix G: IEC 60870-5-103 Communications
Overview ........................................................................................................................................................ G.1
Introduction to IEC 60870-5-103 ................................................................................................................... G.1
IEC 60870-5-103 in the SEL-751................................................................................................................... G.9
IEC 60870-5-103 Documentation ................................................................................................................ G.12
Appendix H: DeviceNet Communications
Overview ........................................................................................................................................................ H.1
DeviceNet Card .............................................................................................................................................. H.1
Features........................................................................................................................................................... H.2
Electronic Data Sheet ..................................................................................................................................... H.3
Appendix I: Synchrophasors
Overview ..........................................................................................................................................................I.1
Synchrophasor Measurement ...........................................................................................................................I.2
Settings for Synchrophasors.............................................................................................................................I.4
Serial Port Settings for IEEE C37.118 Synchrophasors ......................................................................................I.8
Ethernet Port Settings for IEEE C37.118 Synchrophasors ....................................................................................I.9
Synchrophasor Relay Word Bits.....................................................................................................................I.11
View Synchrophasors Using the MET PM Command...................................................................................I.13
C37.118 Synchrophasor Protocol...................................................................................................................I.14
IEEE C37.118 PMU Setting Example............................................................................................................I.16
Appendix J: MIRRORED BITS Communications
Overview ..........................................................................................................................................................J.1
Operation ..........................................................................................................................................................J.1
Settings .............................................................................................................................................................J.5

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SEL-751 Relay Instruction Manual Date Code 20170927
Table of Contents
Appendix K: Relay Word Bits
Overview ........................................................................................................................................................ K.1
Definitions ...................................................................................................................................................... K.6
Appendix L: Analog Quantities
Appendix M: Cybersecurity Features
Access Control................................................................................................................................................M.1
Configuration Management............................................................................................................................M.2
Malware Protection ........................................................................................................................................M.3
Security Vulnerabilities ..................................................................................................................................M.3
Settings Erasure..............................................................................................................................................M.3
Glossary
Index
SEL-751 Relay Command Summary

Date Code 20170927 Instruction Manual SEL-751 Relay
List of Tables
R.Instruct ion Manual Table 1.1 Phase and Neutral Current Ratings Selection for the SEL-751 Models ................................ 1.2
Table 1.2 Current (ACI) and Voltage (AVI) Card Selection for SEL-751 Models ................................ 1.2
Table 1.3 SEL-751 Protection Elements ................................................................................................ 1.2
Table 1.4 SEL-751 Front-Panel Options................................................................................................ 1.4
Table 1.5 SEL-751 Serial Port Settings................................................................................................ 1.10
Table 2.1 Power Supply Inputs (PSIO/2 DI/3 DO) Card Terminal Designations.................................. 2.4
Table 2.2 Communications Ports ........................................................................................................... 2.4
Table 2.3 Communications Card Interfaces and Connectors ................................................................. 2.6
Table 2.4 Current/Voltage Inputs (4 ACI/3 AVI) Card Terminal Designations ..................................... 2.7
Table 2.5 Current Inputs (4 ACI) Card Terminal Designations ............................................................. 2.7
Table 2.6 Voltage/Arc-Flash Detection Inputs (2 AVI/4 AFDI) Card Terminal Designations .............. 2.8
Table 2.7 Eight Arc-Flash Detection Inputs (8 AFDI) Card Terminal Designations............................. 2.8
Table 2.8 Eight Analog Inputs (8 AI) Card Terminal Designations ...................................................... 2.9
Table 2.9 Four Analog Inputs/Four Analog Outputs (4 AI/4 AO) Card Terminal Designations........... 2.9
Table 2.10 I/O (3 DI/4 DO/1 AO) Card Terminal Designations............................................................ 2.10
Table 2.11 RTD (10 RTD) Card Terminal Designations........................................................................ 2.10
Table 2.12 Four Digital Inputs, One Form B Digital Output, Two Form C
Digital Outputs (4 DI/3 DO) Card Terminal Designations............................................... 2.11
Table 2.13 Four Digital Inputs/Four Digital Outputs (4 DI/4 DO) Card Terminal Designations .......... 2.11
Table 2.14 Eight Digital Inputs (8 DI) Card Terminal Designations ..................................................... 2.12
Table 2.15 Eight Digital Outputs (8 DO) Card Terminal Designations................................................. 2.12
Table 2.16 Fourteen Digital Inputs (14 DI) Card Terminal Designations.............................................. 2.13
Table 2.17 Jumper Functions and Default Positions.............................................................................. 2.18
Table 2.18 Typical Maximum RTD Lead Length .................................................................................. 2.26
Table 2.19 Optical Budget Calculations................................................................................................. 2.48
Table 3.1 SEL Software Solutions ......................................................................................................... 3.1
Table 3.2 ACSELERATOR QuickSet SEL-5030 Software....................................................................... 3.1
Table 3.3 File/Tools Menus.................................................................................................................... 3.7
Table 3.4 QuickSet Help ...................................................................................................................... 3.18
Table 4.1 Identifier Settings ................................................................................................................... 4.3
Table 4.2 CT Configuration Settings ..................................................................................................... 4.4
Table 4.3 Voltage Configuration Settings .............................................................................................. 4.4
Table 4.4 Effect on Group Settings When SINGLEV := Y ................................................................... 4.5
Table 4.5 Main Relay Functions That Change With VNOM := OFF.................................................... 4.7
Table 4.6 Line Parameter Settings ....................................................................................................... 4.10
Table 4.7 Fault Locator Setting............................................................................................................ 4.11
Table 4.8 Maximum Phase Overcurrent Settings................................................................................. 4.12
Table 4.9 Neutral Overcurrent Settings................................................................................................ 4.13
Table 4.10 Residual Overcurrent Settings.............................................................................................. 4.15
Table 4.11 Negative-Sequence Overcurrent Settings............................................................................. 4.15
Table 4.12 A-, B-, and C-Phase Time-Overcurrent Settings.................................................................. 4.17
Table 4.13 Maximum Phase Time-Overcurrent..................................................................................... 4.18
Table 4.14 Negative-Sequence Time-Overcurrent Settings ................................................................... 4.19
Table 4.15 Neutral Time-Overcurrent Settings ......................................................................................4.20
Table 4.16 Residual Time-Overcurrent Settings .................................................................................... 4.21
Table 4.17 Equations Associated With U.S. Curves.............................................................................. 4.23
Table 4.18 Equations Associated With IEC Curves............................................................................... 4.23
Table 4.19 Available Ground Directional Elements............................................................................... 4.28
Table 4.20 Best Choice Ground Directional Element Logic.................................................................. 4.29
Table 4.21 Ground Directional Element Availability by Voltage Connection Settings ......................... 4.30
Table 4.22 Directional Control Settings................................................................................................. 4.53
Table 4.23 Wattmetric Settings .............................................................................................................. 4.54
Table 4.24 Directional Control Settings Not Made for Particular Conditions....................................... 4.56

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SEL-751 Relay Instruction Manual Date Code 20170927
List of Tables
Table 4.25 Overcurrent Elements Controlled by Level Direction Settings DIR1 Through DIR4
(Corresponding Overcurrent Element Figure Numbers in Parentheses) .......................... 4.56
Table 4.26 Effect of Settings VSCONN and DELTA_Y on Petersen Coil Directional Elements ......... 4.76
Table 4.27 Load-Encroachment Settings ............................................................................................... 4.78
Table 4.28 High-Impedance Fault (HIF) Detection Settings ................................................................. 4.84
Table 4.29 HIF Relay Word Bits............................................................................................................ 4.85
Table 4.30 Second-Harmonic Blocking Settings ................................................................................... 4.87
Table 4.31 RTD Settings ........................................................................................................................ 4.89
Table 4.32 RTD Resistance Versus Temperature ................................................................................... 4.90
Table 4.33 IEC Thermal Element Settings............................................................................................. 4.96
Table 4.34 Undervoltage Function......................................................................................................... 4.97
Table 4.35 Overvoltage Function........................................................................................................... 4.98
Table 4.36 Operating Quantities for the 27I Element .......................................................................... 4.101
Table 4.37 Inverse-Time Undervoltage Settings .................................................................................. 4.102
Table 4.38 Specification Of Inverse-Time Undervoltage Protection Element..................................... 4.102
Table 4.39 Operating Quantities for the 59I Element .......................................................................... 4.103
Table 4.40 Inverse-Time Overvoltage Settings .................................................................................... 4.104
Table 4.41 Specification of Inverse-Time Overvoltage Protection Element........................................ 4.105
Table 4.42 Synchronism-Check Settings .............................................................................................4.108
Table 4.43 Voltages When Setting SINGLEV := Y............................................................................. 4.115
Table 4.44 Power Element Settings...................................................................................................... 4.115
Table 4.45 Power Factor Settings......................................................................................................... 4.117
Table 4.46 Loss-of-Potential (LOP) Setting......................................................................................... 4.119
Table 4.47 Vector Shift Element Settings ............................................................................................ 4.123
Table 4.48 Frequency Settings ............................................................................................................. 4.123
Table 4.49 Rate-of-Change-of-Frequency Settings.............................................................................. 4.124
Table 4.50 Time Window Versus 81RnTP Setting............................................................................... 4.125
Table 4.51 Fast Rate-of-Change-of-Frequency Settings...................................................................... 4.127
Table 4.52 Trip/Close Logic Settings................................................................................................... 4.129
Table 4.53 Relay Word Bit and Front-Panel Correspondence to Reclosing Relay States ................... 4.139
Table 4.54 Reclosing Control Settings................................................................................................. 4.141
Table 4.55 Shot Counter Correspondence to Relay Word Bits and Open Interval Times ................... 4.144
Table 4.56 Open Interval Time Example Settings ............................................................................... 4.148
Table 4.57 Demand Meter Settings...................................................................................................... 4.154
Table 4.58 Enable Settings................................................................................................................... 4.158
Table 4.59 Latch Bits Equation Settings.............................................................................................. 4.159
Table 4.60 SELOGIC Control Equation Operators (Listed in Operator Precedence) ........................... 4.162
Table 4.61 Other SELOGIC Control Equation Operators/Values.......................................................... 4.165
Table 4.62 SELOGIC Variable Settings................................................................................................. 4.165
Table 4.63 Counter Input/Output Description...................................................................................... 4.166
Table 4.64 Order of Precedence of the Control Inputs......................................................................... 4.167
Table 4.65 Control Output Equations and Contact Behavior Settings................................................. 4.168
Table 4.66 General Global Settings ..................................................................................................... 4.169
Table 4.67 Event Messenger Settings .................................................................................................. 4.170
Table 4.68 Setting Group Selection ..................................................................................................... 4.171
Table 4.69 LEA Ratio and Phase Correction Settings for Phase Voltages........................................... 4.171
Table 4.70 LEA Ratio and Phase Correction Settings for Synchronism-Check Voltage..................... 4.172
Table 4.71 Time and Date Management Settings ................................................................................ 4.172
Table 4.72 Breaker Failure Setting....................................................................................................... 4.174
Table 4.73 Arc-Flash Overcurrent Settings.......................................................................................... 4.176
Table 4.74 Arc-Flash Time-Overlight Settings .................................................................................... 4.177
Table 4.75 Typical Ambient Illumination Light Levels....................................................................... 4.179
Table 4.76 Summary of Steps .............................................................................................................. 4.181
Table 4.77 Analog Input Card Settings in Slot 3 ................................................................................. 4.183
Table 4.78 Analog Output Card Settings in Slot 3............................................................................... 4.184
Table 4.79 Slot C Input Debounce Settings .........................................................................................4.187
Table 4.80 Data Reset Settings............................................................................................................. 4.187

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Date Code 20170927 Instruction Manual SEL-751 Relay
List of Tables
Table 4.81 Setting Change Disable Setting.......................................................................................... 4.187
Table 4.82 Time Synchronization Source Setting................................................................................ 4.188
Table 4.83 Front-Panel Serial Port Settings ......................................................................................... 4.188
Table 4.84 Ethernet Port Settings......................................................................................................... 4.189
Table 4.85 Port Number Settings That Must be Unique...................................................................... 4.190
Table 4.86 Fiber-Optic Serial Port Settings ......................................................................................... 4.191
Table 4.87 Rear-Panel Serial Port (EIA-232) Settings......................................................................... 4.191
Table 4.88 Rear-Panel Serial Port (EIA-232/EIA-485) Settings.......................................................... 4.192
Table 4.89 Rear-Panel DeviceNet Port Settings................................................................................... 4.193
Table 4.90 Display Point and Local Bit Default Settings .................................................................... 4.194
Table 4.91 LCD Display Settings......................................................................................................... 4.194
Table 4.92 Settings That Always, Never, or Conditionally Hide a Display Point ............................... 4.196
Table 4.93 Entries for the Four Strings ................................................................................................ 4.196
Table 4.94 Binary Entry in the Name String Only............................................................................... 4.198
Table 4.95 Analog Entry in the Name String Only.............................................................................. 4.199
Table 4.97 Example Settings and Displays..........................................................................................4.200
Table 4.96 Entry in the Name String and the Alias Strings ................................................................. 4.200
Table 4.98 Target LED Settings ........................................................................................................... 4.203
Table 4.99 Pushbutton LED Settings ................................................................................................... 4.204
Table 4.100 Auto-Removal Settings ...................................................................................................... 4.206
Table 4.101 SER Trigger Settings.......................................................................................................... 4.206
Table 4.102 Enable Alias Settings ......................................................................................................... 4.206
Table 4.103 SET R SER Alias Settings ................................................................................................. 4.207
Table 4.104 Event Report Settings......................................................................................................... 4.207
Table 4.105 HIF Event Report Settings ................................................................................................. 4.208
Table 4.106 Load Profile Settings.......................................................................................................... 4.208
Table 4.107 DNP Map Settings.............................................................................................................. 4.208
Table 4.108 User Map Register Settings ............................................................................................... 4.209
Table 5.1 Measured Fundamental Meter Values.................................................................................... 5.3
Table 5.2 Thermal Meter Values ............................................................................................................ 5.5
Table 5.3 RTD Input Status Messages ................................................................................................... 5.6
Table 5.4 Maximum/Minimum Meter Values........................................................................................ 5.7
Table 5.5 RMS Meter Values ................................................................................................................. 5.9
Table 5.6 Demand Values..................................................................................................................... 5.11
Table 5.7 Synchrophasor Measured Values ......................................................................................... 5.12
Table 5.8 High-Impedance Fault Metering Measured Values.............................................................. 5.13
Table 5.9 Station DC Battery Monitor Settings ................................................................................... 5.15
Table 5.10 Breaker Maintenance Information for a 25 kV Circuit Breaker .......................................... 5.19
Table 5.11 Breaker Monitor Settings ..................................................................................................... 5.20
Table 6.1 Methods of Accessing Settings .............................................................................................. 6.1
Table 6.2 SHOW Command Options..................................................................................................... 6.4
Table 6.3 SET Command Options ......................................................................................................... 6.4
Table 6.4 SET Command Editing Keystrokes........................................................................................ 6.5
Table 6.5 SET Command Format........................................................................................................... 6.6
Table SET.1 Range Dependencies for the EDIR Setting ....................................................................... SET.6
Table SET.2 Range Dependencies for the ORDER Setting ................................................................... SET.6
Table SET.3 Range Dependencies for 27I Operating Quantities......................................................... SET.13
Table SET.4 Range Dependencies for 59I Operating Quantities......................................................... SET.14
Table SET.5 Port Number Settings That Must be Unique ...................................................................SET.51
Table 7.1 SEL-751 Communications Port Interfaces............................................................................. 7.1
Table 7.2 PRP Settings........................................................................................................................... 7.6
Table 7.3 EIA-232/EIA-485 Serial Port Pin Functions ......................................................................... 7.8
Table 7.4 Protocols Supported on the Various Ports............................................................................ 7.11
Table 7.5 Settings Associated With SNTP...........................................................................................7.15
Table 7.6 Serial Port Automatic Messages ..........................................................................................7.17
Table 7.7 Command Response Header Definitions ............................................................................. 7.19
Table 7.8 Access Commands ............................................................................................................... 7.20

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SEL-751 Relay Instruction Manual Date Code 20170927
List of Tables
Table 7.9 ANALOG Command ........................................................................................................... 7.23
Table 7.10 COM Command ................................................................................................................... 7.28
Table 7.11 CONTROL Command ......................................................................................................... 7.28
Table 7.12 Three Remote Bit States....................................................................................................... 7.29
Table 7.13 COPY Command.................................................................................................................. 7.29
Table 7.14 COUNTER Command ......................................................................................................... 7.29
Table 7.15 Date Command..................................................................................................................... 7.29
Table 7.16 EVENT Command (Event Reports)..................................................................................... 7.32
Table 7.17 FILE Command.................................................................................................................... 7.32
Table 7.18 GOOSE Command Variants.................................................................................................7.33
Table 7.19 GROUP Command............................................................................................................... 7.36
Table 7.20 HELP Command .................................................................................................................. 7.36
Table 7.21 HISTORY Command ........................................................................................................... 7.37
Table 7.22 HIS HIF Command .............................................................................................................. 7.37
Table 7.23 HSG Command .................................................................................................................... 7.38
Table 7.24 IDENTIFICATION Command............................................................................................. 7.39
Table 7.25 INI HIF Command ............................................................................................................... 7.39
Table 7.26 IRI Command....................................................................................................................... 7.39
Table 7.27 LDP Commands ................................................................................................................... 7.40
Table 7.28 L_D Command (Load Firmware) ........................................................................................ 7.40
Table 7.29 LOG HIF Command............................................................................................................. 7.41
Table 7.30 LOO Command.................................................................................................................... 7.41
Table 7.31 Meter Command................................................................................................................... 7.42
Table 7.32 Meter Class........................................................................................................................... 7.43
Table 7.33 PASSWORD Command.......................................................................................................7.44
Table 7.34 Factory-Default Passwords for Access Levels 1, 2, and C................................................... 7.44
Table 7.35 Valid Password Characters................................................................................................... 7.44
Table 7.36 PUL OUTnnn Command ..................................................................................................... 7.46
Table 7.37 QUIT Command................................................................................................................... 7.46
Table 7.38 R_S Command (Restore Factory-Defaults) ......................................................................... 7.46
Table 7.39 SER Command (Sequential Events Recorder Report)......................................................... 7.47
Table 7.40 SER D Command................................................................................................................. 7.47
Table 7.41 SET Command (Change Settings) ....................................................................................... 7.48
Table 7.42 SET Command Editing Keystrokes...................................................................................... 7.48
Table 7.43 SHOW Command (Show/View Settings)............................................................................. 7.49
Table 7.44 STATUS Command (Relay Self-Test Status)....................................................................... 7.51
Table 7.45 STATUS Command Report and Definitions ........................................................................ 7.51
Table 7.46 SUMMARY Command........................................................................................................7.53
Table 7.47 SUM HIF Command ............................................................................................................ 7.53
Table 7.48 TARGET Command (Display Relay Word Bit Status)........................................................ 7.53
Table 7.49 Front-Panel LEDs and the TAR 0 Command....................................................................... 7.54
Table 7.50 TEST DB Commands........................................................................................................... 7.54
Table 7.51 THE Command (Preload or Reset Thermal Capacity)......................................................... 7.56
Table 7.52 TIME Command (View/Change Time)................................................................................ 7.56
Table 7.53 TRIGGER Command (Trigger Event Report) ..................................................................... 7.57
Table 7.54 TRIGGER HIF Command ................................................................................................... 7.57
Table 7.55 VEC Command .................................................................................................................... 7.57
Table 7.56 FTP and MMS Virtual File Structure................................................................................... 7.58
Table 7.57 Settings Directory Files........................................................................................................ 7.60
Table 7.58 Reports Directory Files ........................................................................................................ 7.60
Table 7.59 Event Directory Files ........................................................................................................... 7.61
Table 7.60 Files Available for Ymodem Protocol.................................................................................. 7.62
Table 7.61 FTP and MMS Wildcard Usage Examples .......................................................................... 7.63
Table 7.62 Ymodem Wildcard Usage Examples ................................................................................... 7.63
Table 8.1 Front-Panel Automatic Messages (FP_AUTO := OVERRIDE) ............................................ 8.3
Table 8.2 Front-Panel Pushbutton Functions ......................................................................................... 8.5
Table 8.3 Possible Warning Conditions (Flashing TRIP LED) ........................................................... 8.14
Table 8.4 SEL-751 Front-Panel Operator Control Functions .............................................................. 8.16

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Date Code 20170927 Instruction Manual SEL-751 Relay
List of Tables
Table 8.5 Touchscreen Display Component and Indicator Descriptions ............................................. 8.19
Table 8.6 Front-Panel Automatic Messages......................................................................................... 8.20
Table 8.7 Sidebar Buttons .................................................................................................................... 8.21
Table 8.8 Home Folders and Applications...........................................................................................8.22
Table 8.9 Meter Application Availability............................................................................................. 8.23
Table 8.10 Monitor Application Availability ......................................................................................... 8.25
Table 8.11 Reports Application Availability.......................................................................................... 8.26
Table 8.12 Control Application Availability.......................................................................................... 8.28
Table 8.13 Device Info Application Availability ...................................................................................8.30
Table 8.14 Access Level Application Availability ................................................................................. 8.32
Table 8.15 Settings Folder and Application Availability ....................................................................... 8.33
Table 8.16 Settings Folders Port, Group, and Date and Time Application Availability ........................ 8.33
Table 8.17 Screens Available for the Rotating Display, HOME Pushbutton, and Programmable
Pushbuttons....................................................................................................................... 8.36
Table 9.1 Circuit Breaker Symbols ........................................................................................................ 9.2
Table 9.2 Disconnect Settings................................................................................................................ 9.3
Table 9.3 Two-Position Disconnect Symbols ........................................................................................ 9.3
Table 9.4 Local/Remote Breaker Control Settings ................................................................................ 9.4
Table 9.5 Touchscreen Settings.............................................................................................................. 9.7
Table 9.6 Symbols Required for the Single-Line Diagram Schematic in Figure 9.10......................... 9.16
Table 10.1 Event Types .......................................................................................................................... 10.4
Table 10.2 Phase Involvement Event Type ............................................................................................ 10.5
Table 10.3 Event Report Current and Voltage Columns ........................................................................ 10.9
Table 10.4 Output, Input, Protection, and Control Element Event Report Columns........................... 10.10
Table 10.5 CEV HIF Commands ......................................................................................................... 10.30
Table 10.6 HIF Event Types................................................................................................................. 10.31
Table 10.7 HIF Event Phases ............................................................................................................... 10.31
Table 10.8 HIF Downed Conductor..................................................................................................... 10.32
Table 10.9 SUM HIF Command .......................................................................................................... 10.32
Table 10.10 HIS HIF Command ............................................................................................................ 10.34
Table 11.1 Resultant Scale Factors for Inputs........................................................................................ 11.2
Table 11.2 Serial Port Commands That Clear Relay Data Buffers........................................................ 11.6
Table 11.3 Phase Current Measuring Accuracy..................................................................................... 11.7
Table 11.4 Current Unbalance Measuring Accuracy ............................................................................. 11.8
Table 11.5 Power Quantity Accuracy—Wye Voltages........................................................................... 11.9
Table 11.6 Power Quantity Accuracy—Delta Voltages ....................................................................... 11.10
Table 11.7 Periodic Relay Checks ....................................................................................................... 11.12
Table 11.8 Relay Self-Tests.................................................................................................................. 11.14
Table 11.9 Troubleshooting.................................................................................................................. 11.16
Table A.1 R200 Series Firmware Revision History............................................................................... A.1
Table A.2 R100 Series Firmware Revision History............................................................................... A.3
Table A.3 SEL Display Package Revision History................................................................................ A.7
Table A.4 SEL Display Package Compatibility With Relay Firmware ................................................. A.7
Table A.5 DeviceNet Card Versions ...................................................................................................... A.8
Table A.6 EDS File Compatibility......................................................................................................... A.8
Table A.7 SEL-751 ICD File Revision History ..................................................................................... A.9
Table A.8 Instruction Manual Revision History .................................................................................. A.13
Table C.1 Supported Serial Command Sets............................................................................................C.1
Table C.2 Compressed ASCII Commands .............................................................................................C.2
Table C.3 SEL Communications Processors Protocol Interfaces...........................................................C.4
Table C.4 SEL Communications Processor Port 1 Settings ...................................................................C.7
Table C.5 SEL Communications Processor Data Collection Automessages..........................................C.7
Table C.6 SEL Communications Processor Port 1 Automatic Messaging Settings ...............................C.8
Table C.7 SEL Communications Processor Port 1 Region Map ............................................................C.8
Table C.8 Communications Processor METER Region Map With the 2 AVI/4 AFD Card Installed....C.9
Table C.9 Communications Processor TARGET Region .......................................................................C.9
Table C.10 Communications Processor DEMAND Region Map...........................................................C.11

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SEL-751 Relay Instruction Manual Date Code 20170927
List of Tables
Table D.1 DNP3 Implementation Levels............................................................................................... D.1
Table D.2 Selected DNP3 Function Codes ............................................................................................D.3
Table D.3 DNP3 Access Methods.......................................................................................................... D.4
Table D.4 TCP/UDP Selection Guidelines ............................................................................................D.6
Table D.5 DNP3 Access Methods.......................................................................................................... D.6
Table D.6 SEL-751 Event Buffer Capacity............................................................................................ D.9
Table D.7 Port DNP3 Protocol Settings............................................................................................... D.11
Table D.8 Serial Port DNP3 Modem Settings...................................................................................... D.12
Table D.9 SEL-751 DNP Object List................................................................................................... D.14
Table D.10 DNP3 Reference Data Map................................................................................................. D.19
Table D.11 DNP3 Default Data Map..................................................................................................... D.20
Table D.12 SEL-751 Object 12 Control Operations.............................................................................. D.23
Table D.13 Sample Custom DNP3 AI Map........................................................................................... D.27
Table E.1 Modbus Query Fields.............................................................................................................E.2
Table E.2 SEL-751 Modbus Function Codes .........................................................................................E.2
Table E.3 SEL-751 Modbus Exception Codes .......................................................................................E.3
Table E.4 01h Read Discrete Output Coil Status Command..................................................................E.4
Table E.5 Responses to 01h Read Discrete Output Coil Query Errors ..................................................E.4
Table E.6 02h Read Input Status Command...........................................................................................E.4
Table E.7 02h SEL-751 Inputs ...............................................................................................................E.5
Table E.8 Responses to 02h Read Input Query Errors ...........................................................................E.6
Table E.9 03h Read Holding Register Command...................................................................................E.6
Table E.10 Responses to 03h Read Holding Register Query Errors ........................................................E.6
Table E.11 04h Read Input Register Command .......................................................................................E.7
Table E.12 Responses to 04h Read Input Register Query Errors.............................................................E.7
Table E.13 05h Force Single Coil Command...........................................................................................E.7
Table E.14 01h, 05h SEL-751 Output ......................................................................................................E.8
Table E.15 Responses to 05h Force Single Coil Query Errors...............................................................E.10
Table E.16 06h Preset Single Register Command..................................................................................E.10
Table E.17 Responses to 06h Preset Single Register Query Errors........................................................E.11
Table E.18 08h Loopback Diagnostic Command...................................................................................E.11
Table E.19 Responses to 08h Loopback Diagnostic Query Errors.........................................................E.11
Table E.20 10h Preset Multiple Registers Command.............................................................................E.12
Table E.21 10h Preset Multiple Registers Query Error Messages .........................................................E.12
Table E.22 60h Read Parameter Information Command........................................................................E.12
Table E.23 60h Read Parameter Descriptor Field Definition.................................................................E.13
Table E.24 60h Read Parameter Conversion Field Definition................................................................E.13
Table E.25 Responses to 60h Read Parameter Information Query Errors .............................................E.14
Table E.26 61h Read Parameter Text Command....................................................................................E.14
Table E.27 61h Read Parameter Text Query Error Messages.................................................................E.15
Table E.28 62h Read Enumeration Text Command ...............................................................................E.15
Table E.29 61h Read Parameter Enumeration Text Query Error Messages...........................................E.15
Table E.30 7Dh Encapsulated Packet With Control Command .............................................................E.15
Table E.31 7Dh Encapsulated Packet Query Errors ...............................................................................E.16
Table E.32 7Eh NOP Command.............................................................................................................E.16
Table E.33 Modbus Register Labels for Use With SET M Command...................................................E.18
Table E.34 Modbus Register Map ..........................................................................................................E.25
Table F.1 IEC 61850 Document Set....................................................................................................... F.2
Table F.2 Example IEC 61850 Descriptor Components........................................................................ F.4
Table F.3 SEL-751 Logical Devices ...................................................................................................... F.4
Table F.4 Buffered Report Control Block Client Access....................................................................... F.8
Table F.5 Unbuffered Report Control Block Client Access................................................................... F.8
Table F.6 IEC 61850 Settings............................................................................................................... F.11
Table F.7 New Logical Node Extensions.............................................................................................F.13
Table F.8 Arc-Flash Detection Logical Node Class Definition ........................................................... F.13
Table F.9 Thermal Metering Data Logical Node Class Definition ...................................................... F.13
Table F.10 Thermal Element Metering Data Logical Node Class Definition........................................ F.14

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Date Code 20170927 Instruction Manual SEL-751 Relay
List of Tables
Table F.11 Metering Statistics Logical Node Class Definition.............................................................. F.15
Table F.12 Demand Metering Statistics Logical Node Class Definition ............................................... F.15
Table F.13 Compatible Logical Nodes With Extensions ....................................................................... F.16
Table F.14 Fault Locator Logical Node Class Definition ...................................................................... F.16
Table F.15 Circuit Breaker Logical Node Class Definition ................................................................... F.17
Table F.16 Measurement Logical Node Class Definition ...................................................................... F.17
Table F.17 Measurement Logical Node Class Definition ...................................................................... F.18
Table F.18 Generic Process I/O Logical Node Class Definition............................................................ F.18
Table F.19 Circuit Breaker Supervision (Per-Phase) Logical Node Class Definition .......................... F.18
Table F.20 Logical Device: PRO (Protection)........................................................................................ F.19
Table F.21 Logical Device: MET (Metering).........................................................................................F.31
Table F.22 Logical Device: CON (Remote Control).............................................................................. F.35
Table F.23 Logical Device: ANN (Annunciation) ................................................................................. F.36
Table F.24 Logical Device: CFG (Configuration) ................................................................................. F.42
Table F.25 PICS for A-Profile Support .................................................................................................. F.42
Table F.26 PICS for T-Profile Support................................................................................................... F.42
Table F.27 MMS Service Supported Conformance ............................................................................... F.43
Table F.28 MMS Parameter CBB .......................................................................................................... F.45
Table F.29 AlternateAccessSelection Conformance Statement............................................................. F.45
Table F.30 VariableAccessSpecification Conformance Statement ........................................................ F.46
Table F.31 VariableSpecification Conformance Statement.................................................................... F.46
Table F.32 Read Conformance Statement.............................................................................................. F.46
Table F.33 GetVariableAccessAttributes Conformance Statement........................................................ F.46
Table F.34 DefineNamedVariableList Conformance Statement ............................................................ F.46
Table F.35 GetNamedVariableListAttributes Conformance Statement ................................................. F.47
Table F.36 DeleteNamedVariableList .................................................................................................... F.47
Table F.37 GOOSE Conformance.......................................................................................................... F.47
Table F.38 ACSI Basic Conformance Statement ................................................................................... F.48
Table F.39 ACSI Models Conformance Statement ................................................................................ F.48
Table F.40 ACSI Services Conformance Statement............................................................................... F.49
Table G.1 IEC 60870-5 Standard Documents........................................................................................ G.1
Table G.2 IEC 60870-5 Enhanced Performance Architecture Model ................................................... G.2
Table G.3 History of IEC 60870-5......................................................................................................... G.2
Table G.4 SEL-751 ASDU Types .......................................................................................................... G.3
Table G.5 IEC 60870-5-103 Category Map Settings............................................................................. G.4
Table G.6 IEC 60870-5-103 Cause Of Transmission ............................................................................ G.5
Table G.7 IEC 60870-5-103 Information Numbers............................................................................... G.5
Table G.8 IEC 60870-5-103 Standard Function Types.......................................................................... G.6
Table G.9 IEC 60870-5-103 Data Map.................................................................................................. G.6
Table G.10 SEL-751 IEC 60870-5-103 Port Settings.............................................................................. G.9
Table G.11 SEL-751 Analog Fault Quantities....................................................................................... G.10
Table I.1 PMU Settings in the SEL-751 for C37.118 Protocol in Global Settings ................................I.4
Table I.2 Synchrophasor Order in Data Stream (Voltages and Currents)...............................................I.6
Table I.3 User-Defined Analog Values Selected by the NUMANA Setting ..........................................I.7
Table I.4 User-Defined Digital Status Words Selected by the NUMDSW Setting ................................I.7
Table I.5 SEL-751 Serial Port Settings for Synchrophasors ..................................................................I.8
Table I.6 SEL-751 Ethernet Port Settings for Synchrophasors ..............................................................I.9
Table I.7 Synchrophasor Trigger Relay Word Bits ..............................................................................I.11
Table I.8 Time Synchronization Relay Word Bits................................................................................I.11
Table I.9 TQUAL Bits Translation to Time Quality.............................................................................I.12
Table I.10 Size of a C37.118 Synchrophasor Message ..........................................................................I.15
Table I.11 Serial Port Bandwidth for Synchrophasors (in Bytes) ..........................................................I.15
Table I.12 Example Synchrophasor Global Settings..............................................................................I.18
Table I.13 Example Synchrophasor Logic Settings ...............................................................................I.18
Table I.14 Example Synchrophasor SELOGIC Settings..........................................................................I.18
Table I.15 Example Synchrophasor Port Settings ..................................................................................I.18

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SEL-751 Relay Instruction Manual Date Code 20170927
List of Tables
Table J.1 Number of MIRRORED BITS Messages for Different Data Rates ............................................J.2
Table J.2 Positions of the MIRRORED BITS .............................................................................................J.3
Table J.3 MIRRORED BITS Values for a RXDFLT Setting of 10100111.................................................J.3
Table J.4 MIRRORED BITS Communications Message Transmission Period..........................................J.5
Table J.5 MIRRORED BITS Protocol Settings ..........................................................................................J.5
Table K.1 SELOGIC Relay Word Bits .................................................................................................... K.1
Table K.2 Relay Word Bit Definitions for the SEL-751 Relay.............................................................. K.6
Table L.1 Analog Quantities...................................................................................................................L.1
Table M.1 IP Port Numbers....................................................................................................................M.1

Date Code 20170927 Instruction Manual SEL-751 Relay
List of Figures
R.Instruct ion Manual Figure 1.1 SEL-751 Feeder Protection Relay Applied Throughout the Power System .......................... 1.8
Figure 1.2 Typical Current Connections.................................................................................................. 1.9
Figure 1.3 Response Header.................................................................................................................. 1.10
Figure 1.4 STA Command Response—No Communications Card or EIA-232/EIA-485
Communications Card ...................................................................................................... 1.11
Figure 1.5 STA Command Response—Communications Card/DeviceNet Protocol............................ 1.11
Figure 2.1 Relay Panel-Mount Dimensions............................................................................................. 2.2
Figure 2.2 Slot Allocations for Different Cards ...................................................................................... 2.3
Figure 2.3 Circuit Board of Analog I/O Board, Showing Jumper Selection......................................... 2.17
Figure 2.4 JMP1 Through JMP4 Locations on 4 AI/4 AO Board......................................................... 2.17
Figure 2.5 Current Output Jumpers ....................................................................................................... 2.17
Figure 2.6 Voltage Output Jumpers ....................................................................................................... 2.17
Figure 2.7 Pins for Password, Breaker Control, and SELBOOT Jumper................................................ 2.18
Figure 2.8 Dual Fiber Ethernet With 2 AVI/4 AFDI Voltage Option With Arc-Flash
Detector Inputs, DeviceNet Card, and Fast Hybrid 4 DI/4 DO Card
(Relay MOT 751501AA3CA70850830) .......................................................................... 2.19
Figure 2.9 Single Copper Ethernet, EIA-485 Communication, 8 DO (Form A) Card,
4 AI/4 AO Card, and 2 AVI/4 AFDI Voltage Option With Arc-Flash Detector Inputs
(Relay MOT 751201A2A6X70810320)........................................................................... 2.20
Figure 2.10 Single Copper Ethernet With EIA-232 Communication, 10 RTD Card, 4 DI/4 DO Card
and 2 AVI/4 AFDI Voltage Option Card With Arc-Flash Detector Inputs
(Relay MOT 751501A1A9X70850230)........................................................................... 2.20
Figure 2.11 No Ethernet, EIA-232 Serial Communications, EIA-232/EIA-485 Communications
Card, 8 DI Card, and 8 DO Card (Form A) (Relay MOT 751401AA03A2A850000)..... 2.21
Figure 2.12 Dual Copper Ethernet, 4 DI/4 DO Card, 14 DI Card, 8 AFDI With Arc-Flash Detector
Inputs, 4 ACI/3 AVI Card With 5 A Phase, 200 mA Neutral, and Three-Phase
AC Voltage Inputs (300 Vac) (Relay MOT 7515S1A1A4A77870671) ........................... 2.21
Figure 2.13 Dual Copper Ethernet, 14 DI Card, 8 DO (Form B) Card, 2 AVI/4 AFDI Card
With LEA Vsync, Vbat Inputs, and 4 Arc-Flash Detection Inputs, 4 ACI/3 AVI Card
With 5 A Phase, 200 mA Neutral, and Three-Phase LEA Voltage Inputs (8 Vac)
(Relay MOT 751501A4A2BL0L70671) .......................................................................... 2.22
Figure 2.14 Dual 10/100 Base-T Ethernet, EIA-232 Rear Port, Without Single Multimode
ST Fiber-Optic Serial Port Rear, With DeviceNet Card, Fast Hybrid 4 DI/4 DO Card,
8 DI Card and 4 ACI Card (No Voltage Inputs)
(Relay MOT 751001AA3CA3AA50F30) ........................................................................ 2.22
Figure 2.15 Control I/O Connections—4 AI/4 AO Option in Slot D and Fiber-Optic Port in Slot B..... 2.25
Figure 2.16 Control I/O Connections—Internal RTD Option in Slot D.................................................. 2.25
Figure 2.17 Analog Output Wiring Example........................................................................................... 2.26
Figure 2.18 Output OUT103 Relay Output Contact Configuration ........................................................ 2.26
Figure 2.19 OUT103 Contact Fail-Safe and Nonfail-Safe Options......................................................... 2.27
Figure 2.20 Single-Phase Voltage Connections....................................................................................... 2.28
Figure 2.21 Voltage Connections............................................................................................................. 2.29
Figure 2.22 Typical Current Connections................................................................................................ 2.31
Figure 2.23 SEL-751 Provides Overcurrent Protection and Reclosing for a Distribution Feeder
(Includes Fast Bus Trip Scheme) (Delta-Connected PTs)................................................ 2.32
Figure 2.24 SEL-751 Provides Overcurrent Protection for a Distribution Bus
(Includes Fast Bus Trip Scheme) (Wye-Connected PTs) ................................................. 2.33
Figure 2.25 Transmission Line Directional Overcurrent Protection and Reclosing
With Current-Polarization Source Connected to Channel IN (Wye-Connected PTs)...... 2.34
Figure 2.26 SEL-751 Provides Overcurrent Protection for a Delta-Wye Transformer Bank
(Wye-Connected PTs)....................................................................................................... 2.35

xiv
SEL-751 Relay Instruction Manual Date Code 20170927
List of Figures
Figure 2.27 SEL-751 Provides Overcurrent Protection for a Transformer Bank With a Tertiary
Winding (Wye-Connected PTs)........................................................................................ 2.36
Figure 2.28 SEL-751 Provides Overcurrent Protection for an Industrial Distribution Feeder
(Core-Balance Current Transformer Connected to Channel IN)...................................... 2.37
Figure 2.29 SEL-751 Provides Overcurrent Protection for a High-Impedance or Low-Impedance
Grounded System (Wye-Connected PTs)......................................................................... 2.38
Figure 2.30 SEL-751 Provides Overcurrent Protection for a Petersen Coil-Grounded System
(Wye-Connected PTs)....................................................................................................... 2.39
Figure 2.31 SEL-751 Provides Overcurrent Protection for an Ungrounded System
(Wye-Connected PTs)....................................................................................................... 2.40
Figure 2.32 SEL-751 Provides Overcurrent Protection for an Ungrounded System
(Open-Delta Connected PTs, Broken-Delta 3V0 Connection)......................................... 2.41
Figure 2.33 SEL-751 With a 2 AVI/4 AFDI Option Card and the Fiber-Optic-Based Point-Sensor...... 2.42
Figure 2.34 Black-Jacketed Fiber installation Example .......................................................................... 2.43
Figure 2.35 Point-Sensor Assembly ........................................................................................................ 2.43
Figure 2.36 Point-Sensor Installation ...................................................................................................... 2.43
Figure 2.37 Point-Sensor Directivity (0–360° Around the Mounting Plane).......................................... 2.44
Figure 2.38 Point-Sensor Directivity (Front to Back, Above the Mounting Plane) ................................ 2.44
Figure 2.39 Point-Sensor Directivity (Left to Right, Above the Mounting Plane).................................. 2.45
Figure 2.40 Clear-Jacketed Fiber Sensor Assembly................................................................................ 2.45
Figure 2.41 Clear-Jacketed Fiber Sensor Mounting Example................................................................. 2.46
Figure 2.42 Clear-Jacketed Fiber Sensor Components (V-Pin Style)...................................................... 2.46
Figure 2.43 Clear-Jacketed Fiber Sensor Showing Transition From Clear- to Black-Jacketed
Fiber Section..................................................................................................................... 2.46
Figure 2.44 Switchgear Application Example......................................................................................... 2.47
Figure 2.45 Bare-Fiber Sensor Assembly With Two Splices .................................................................. 2.48
Figure 2.46 Point Sensor Assembly......................................................................................................... 2.48
Figure 2.47 Bare-Fiber Sensor Assembly With Two Additional ST Splice Connectors......................... 2.49
Figure 2.48 Point Sensor Assembly With Two V-Pin Splice Connectors ............................................... 2.50
Figure 3.1 Serial Port Communications Dialog Box............................................................................... 3.2
Figure 3.2 Serial Port Communication Parameters Dialog Box.............................................................. 3.3
Figure 3.3 Network Communication Parameters Dialog Box................................................................. 3.3
Figure 3.4 Communications Menu .......................................................................................................... 3.3
Figure 3.5 Device Response to the ID Command ................................................................................... 3.4
Figure 3.6 Selection of Drivers................................................................................................................ 3.7
Figure 3.7 Update Part Number............................................................................................................... 3.8
Figure 3.8 New Setting Screen ................................................................................................................ 3.8
Figure 3.9 Expressions Created With Expression Builder .................................................................... 3.10
Figure 3.10 Composite Screens for Retrieving Events............................................................................ 3.11
Figure 3.11 Saving the Retrieved Event .................................................................................................. 3.12
Figure 3.12 Device Overview Screen ...................................................................................................... 3.13
Figure 3.13 Control Screen...................................................................................................................... 3.14
Figure 3.14 Remote Operation Selection................................................................................................. 3.15
Figure 3.15 Language Support Options................................................................................................... 3.15
Figure 3.16 Spanish Settings QuickSet Display...................................................................................... 3.16
Figure 3.17 Spanish Control Window (Ventana de Control) Display ..................................................... 3.17
Figure 4.1 Low-Energy Analog Voltage Sensor (Capacitive Voltage Divider) ....................................... 4.7
Figure 4.2 Instantaneous Overcurrent Element Logic........................................................................... 4.14
Figure 4.3 Instantaneous Overcurrent Element Pickup Time Curve ..................................................... 4.16
Figure 4.4 Instantaneous Overcurrent Element Reset Time Curve ....................................................... 4.16
Figure 4.5 Phase Time-Overcurrent Elements 51AT, 51BT, and 51CT ................................................ 4.18
Figure 4.6 Maximum Phase Time-Overcurrent Elements 51P1T and 51P2T....................................... 4.19
Figure 4.7 Negative-Sequence Time-Overcurrent Element 51QT ........................................................ 4.20
Figure 4.8 Neutral Time-Overcurrent Elements 51N1T and 51N2T..................................................... 4.21
Figure 4.9 Residual Time-Overcurrent Elements 51G1T and 51G2T................................................... 4.22
Figure 4.10 U.S. Moderately Inverse Curve: U1.....................................................................................4.24
Figure 4.11 U.S. Inverse Curve: U2 ........................................................................................................ 4.24
Figure 4.12 U.S. Very Inverse Curve: U3................................................................................................ 4.24

xv
Date Code 20170927 Instruction Manual SEL-751 Relay
List of Figures
Figure 4.13 U.S. Extremely Inverse Curve: U4....................................................................................... 4.24
Figure 4.14 U.S. Short-Time Inverse Curve: U5 .....................................................................................4.25
Figure 4.15 IEC Class A Curve (Standard Inverse): C1.......................................................................... 4.25
Figure 4.16 IEC Class B Curve (Very Inverse): C2................................................................................. 4.25
Figure 4.17 IEC Class C Curve (Extremely Inverse): C3........................................................................ 4.25
Figure 4.18 IEC Long-Time Inverse Curve: C4 ...................................................................................... 4.26
Figure 4.19 IEC Short-Time Inverse Curve: C5......................................................................................4.26
Figure 4.20 General Logic Flow of Directional Control for Neutral Ground and Residual Ground
Overcurrent Elements (Excluding Ungrounded/High-Impedance
Grounded Systems)........................................................................................................... 4.27
Figure 4.21 General Logic Flow of Directional Control for Neutral Ground and Residual
Ground Overcurrent Elements (Ungrounded/High-Impedance Grounded Systems;
ORDER := U) ................................................................................................................... 4.28
Figure 4.22 Logic for Relay Word bit GNDSW...................................................................................... 4.32
Figure 4.23 Internal Enables (DIRQE and DIRQGE) Logic for Negative-Sequence
Voltage-Polarized Directional Elements........................................................................... 4.36
Figure 4.24 Internal Enables (DIRVE and DIRIE) Logic for Zero-Sequence Voltage-Polarized
and Channel IN Current-Polarized Directional Elements ................................................ 4.37
Figure 4.25 Internal Enable (DIRNE) Logic for Zero-Sequence Voltage-Polarized Directional
Elements (Low-Impedance Grounded, Petersen Coil-Grounded, and
Ungrounded/High-Impedance Grounded Systems).......................................................... 4.38
Figure 4.26 Negative-Sequence Voltage-Polarized Directional Element for Neutral Ground
and Residual Ground Overcurrent Elements .................................................................... 4.39
Figure 4.27 Zero-Sequence Voltage-Polarized Directional Element....................................................... 4.40
Figure 4.28 Channel IN Current-Polarized Directional Element ............................................................ 4.41
Figure 4.29 Zero-Sequence Voltage-Polarized Directional Element (Low-Impedance
Grounded Systems)........................................................................................................... 4.42
Figure 4.30 Wattmetric and Incremental Conductance Directional Elements (Petersen
Coil-Grounded Systems) .................................................................................................. 4.43
Figure 4.31 Zero-Sequence Voltage-Polarized Directional Element (Ungrounded/High-Impedance
Grounded Systems)........................................................................................................... 4.44
Figure 4.32 Routing of Directional Elements to Residual Ground Overcurrent Elements ..................... 4.45
Figure 4.33 Routing of Directional Elements to Neutral Ground Overcurrent Elements ....................... 4.45
Figure 4.34 Direction Forward/Reverse Logic for Residual Ground Overcurrent Elements .................. 4.46
Figure 4.35 Direction Forward/Reverse Logic for Neutral Ground Overcurrent Elements .................... 4.47
Figure 4.36 General Logic Flow of Directional Control for Negative-Sequence and Phase
Overcurrent Elements ....................................................................................................... 4.48
Figure 4.37 Negative-Sequence Voltage-Polarized Directional Element for Negative-Sequence
and Phase Overcurrent Elements...................................................................................... 4.50
Figure 4.38 Positive-Sequence Voltage-Polarized Directional Element for Phase Overcurrent
Elements ........................................................................................................................... 4.51
Figure 4.39 Routing of Directional Elements to Negative-Sequence and Phase Overcurrent
Elements ........................................................................................................................... 4.52
Figure 4.40 Direction Forward/Reverse Logic for Negative-Sequence Overcurrent Elements .............. 4.52
Figure 4.41 Direction Forward/Reverse Logic for Phase Overcurrent Elements.................................... 4.53
Figure 4.42 Traditional Channel IN Current-Polarized Directional Element.......................................... 4.61
Figure 4.43 Current-Polarized Directional Element Characteristic When INMTA 0.00 ..................... 4.62
Figure 4.44 Zero-Sequence Impedance Network and Relay Polarity ..................................................... 4.64
Figure 4.45 Zero-Sequence Impedance Plot for Solidly-Grounded, Mostly Inductive System .............. 4.64
Figure 4.46 Low-Impedance Grounded Distribution System With a Ground Fault on Feeder 1............ 4.65
Figure 4.47 Zero-Sequence Impedance Network for Low-Impedance Grounded Distribution
System With a Ground Fault on Feeder 1......................................................................... 4.66
Figure 4.48 Decreasing Neutral Resistance RGResults in Increasing Zero-Sequence Current IOG ....... 4.67
Figure 4.49 Decreasing Neutral Resistance RGResults in Increasing Zero-Sequence Current I0(1)
(Seen by Relay 1) ............................................................................................................. 4.67
Figure 4.50 Zero-Sequence Impedance Plots for Ground Fault on Low-Impedance
Grounded Distribution System ......................................................................................... 4.68

xvi
SEL-751 Relay Instruction Manual Date Code 20170927
List of Figures
Figure 4.51 Z0MTA Setting Provides Forward/Reverse Ground Fault Discrimination
in a Low-Impedance Grounded Distribution System ....................................................... 4.69
Figure 4.52 Zero-Sequence Impedance Network for Ground Fault on Feeder 1 .................................... 4.72
Figure 4.53 Wattmetric Element Operation for Ground Fault on Feeder 1............................................. 4.73
Figure 4.54 Load-Encroachment Logic................................................................................................... 4.79
Figure 4.55 High-Impedance Fault Current Levels Depend on Ground Surface Type ........................... 4.81
Figure 4.56 HIF Detection Block Diagram ............................................................................................. 4.83
Figure 4.57 A-Phase Second Harmonic Blocking................................................................................... 4.86
Figure 4.58 Three-Phase Second- and Fifth-Harmonic Blocking Logic................................................. 4.87
Figure 4.59 Thermal Alarm and Trip Logic ............................................................................................ 4.94
Figure 4.60 Thermal Element Current Overload Logic........................................................................... 4.94
Figure 4.61 Undervoltage Element Logic................................................................................................ 4.99
Figure 4.62 Overvoltage Element Logic................................................................................................ 4.100
Figure 4.63 Logic Diagram of the Inverse-Time Undervoltage Element .............................................. 4.101
Figure 4.64 Inverse Time-Undervoltage Element Curves ..................................................................... 4.103
Figure 4.65 Logic Diagram of the Inverse-Time Overvoltage Element ................................................ 4.104
Figure 4.66 Inverse Time-Overvoltage Element Curves ....................................................................... 4.105
Figure 4.67 Synchronism-Check Voltage Window and Slip Frequency Elements................................ 4.106
Figure 4.68 Synchronism-Check Elements ........................................................................................... 4.107
Figure 4.69 Angle Difference Between VP and VS Compensated by Breaker Close Time
(fP < fS and VP Shown as Reference in This Example) ................................................ 4.112
Figure 4.70 Three-Phase Power Elements Logic................................................................................... 4.116
Figure 4.71 Power Elements Operation in the Real/Reactive Power Plane........................................... 4.117
Figure 4.72 Power Factor Elements Logic ............................................................................................ 4.118
Figure 4.73 Loss-of-Potential (LOP) Logic........................................................................................... 4.120
Figure 4.74 Logic Diagram of the Vector Shift Element....................................................................... 4.121
Figure 4.75 Over- and Underfrequency Element Logic ........................................................................ 4.124
Figure 4.76 81R Frequency Rate-of-Change Scheme Logic................................................................. 4.125
Figure 4.77 81RF Characteristics .......................................................................................................... 4.126
Figure 4.78 81RF Fast Rate-of-Change-of-Frequency Logic................................................................ 4.128
Figure 4.79 Trip Logic........................................................................................................................... 4.129
Figure 4.80 Close Logic ........................................................................................................................ 4.132
Figure 4.81 Reclose Supervision Logic (Following Open Interval Time-Out) ..................................... 4.132
Figure 4.82 Reclose Supervision Limit Timer Operation...................................................................... 4.133
Figure 4.83 SEL-751 Relays Installed at Both Ends of a Transmission Line in a
High-Speed Reclose Scheme.......................................................................................... 4.136
Figure 4.84 Reclosing Relay States and General Operation.................................................................. 4.138
Figure 4.85 Reclosing Sequence From Reset to Lockout With Example Settings................................ 4.142
Figure 4.86 Reclose Blocking for Islanded Generator .......................................................................... 4.148
Figure 4.87 Sequence Coordination Between the SEL-751 and a Line Recloser ................................. 4.151
Figure 4.88 Operation of SEL-751 Shot Counter for Sequence Coordination With Line Recloser
(Additional Settings Example 1) .................................................................................... 4.151
Figure 4.89 Operation of SEL-751 Shot Counter for Sequence Coordination With Line Recloser
(Additional Settings Example 2) .................................................................................... 4.153
Figure 4.90 Demand Current Logic Outputs ......................................................................................... 4.154
Figure 4.91 Response of Thermal and Rolling Demand Meters to a Step Input
(Setting DMTC = 15 minutes)........................................................................................ 4.155
Figure 4.92 Voltage VS Applied to Series RC Circuit .......................................................................... 4.156
Figure 4.93 Schematic Diagram of a Traditional Latching Device....................................................... 4.159
Figure 4.94 Logic Diagram of a Latch Switch ...................................................................................... 4.159
Figure 4.95 SELOGIC Control Equation Variable/Timers SV01/SV01T–SV32T ................................. 4.160
Figure 4.96 Result of Falling-Edge Operator on a Deasserting Input ................................................... 4.164
Figure 4.97 Example Use of SELOGIC Variables/Timers...................................................................... 4.165
Figure 4.98 Counter 01.......................................................................................................................... 4.166
Figure 4.99 Example of the Effects of the Input Precedence ................................................................ 4.167
Figure 4.100 Phase Rotation Setting ....................................................................................................... 4.169
Figure 4.101 Breaker Failure Logic......................................................................................................... 4.175
Figure 4.102 Arc-Flash Instantaneous Overcurrent Element Logic........................................................ 4.176

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Date Code 20170927 Instruction Manual SEL-751 Relay
List of Figures
Figure 4.103 Inverse Time-Overlight Element Logic.............................................................................. 4.178
Figure 4.104 TOL Element Inverse Curve Characteristic ....................................................................... 4.178
Figure 4.105 Analog Input Card Adaptive Name.................................................................................... 4.180
Figure 4.106 Settings to Configure Input 1 as a 4–20 mA Transducer Measuring Temperatures
Between –50°C and 150°C............................................................................................. 4.183
Figure 4.107 Analog Output Number Allocation .................................................................................... 4.184
Figure 4.108 Analog Output Settings ...................................................................................................... 4.185
Figure 4.109 DC Mode Processing.......................................................................................................... 4.186
Figure 4.110 AC Mode Processing.......................................................................................................... 4.186
Figure 4.111 Timing Diagram for Debounce Timer Operation When Operating in AC Mode .............. 4.186
Figure 4.112 Display Point Settings ........................................................................................................ 4.197
Figure 4.113 Front-Panel Display—Both HV and LV Breakers Open ................................................... 4.197
Figure 4.114 Front-Panel Display—HV Breaker Closed, LV Breaker Open.......................................... 4.197
Figure 4.115 Front-Panel Display—Both HV and LV Breakers Closed................................................. 4.198
Figure 4.116 Front-Panel Display—HV Breaker Open, LV Breaker Closed.......................................... 4.198
Figure 4.117 Front-Panel Display—HV Breaker Open, LV Breaker Closed.......................................... 4.198
Figure 4.118 Front-Panel Display for a Binary Entry in the Name String Only..................................... 4.198
Figure 4.119 Front-Panel Display for an Analog Entry in the Name String Only .................................. 4.199
Figure 4.120 Front-Panel Display for an Entry in (a) Boolean Name and Alias Strings and
(b) Analog Name and User Text and Formatting Strings ............................................... 4.200
Figure 4.121 Front-Panel Display for an Entry in (a) Boolean Name and Alias Strings and
(b) Analog Name, User Text and Formatting Strings, and Engineering Units............... 4.200
Figure 4.122 Adding Temperature Measurement Display Points ........................................................... 4.201
Figure 4.123 Rotating Display................................................................................................................. 4.201
Figure 4.124 Adding Two Local Bits ...................................................................................................... 4.202
Figure 5.1 Complex Power Measurement Conventions .......................................................................... 5.2
Figure 5.2 METER Command Report With Voltage/Arc-Flash Detection 2 AVI/4 AFDI Card
in Slot E and 4 ACI/3 AVI Card in Slot Z .......................................................................... 5.5
Figure 5.3 METER T Command Report With RTDs .............................................................................. 5.6
Figure 5.4 METER E Command Response............................................................................................. 5.7
Figure 5.5 METER RE Command Response .......................................................................................... 5.7
Figure 5.6 METER M Command Response............................................................................................ 5.8
Figure 5.7 METER RM Command Response ......................................................................................... 5.8
Figure 5.8 METER MV Command Response......................................................................................... 5.9
Figure 5.9 METER RMS Command Response....................................................................................... 5.9
Figure 5.10 METER AI Command Response ......................................................................................... 5.10
Figure 5.11 METER L (Light) Command Response............................................................................... 5.10
Figure 5.12 MET DE Command Response ............................................................................................. 5.11
Figure 5.13 MET PE Command Response.............................................................................................. 5.11
Figure 5.14 MET RA Command Response............................................................................................. 5.13
Figure 5.15 MET H (HIF) Command Response ..................................................................................... 5.13
Figure 5.16 LDP Command Response .................................................................................................... 5.15
Figure 5.17 DC Under- and Overvoltage Elements................................................................................. 5.16
Figure 5.18 Create DC Voltage Elements With SELOGIC Control Equations......................................... 5.16
Figure 5.19 Plotted Breaker Maintenance Points for a 25 kV Circuit Breaker ....................................... 5.21
Figure 5.20 SEL-751 Breaker Maintenance Curve for a 25 kV Circuit Breaker .................................... 5.22
Figure 5.21 Operation of SELOGIC Control Equation Breaker Monitor Initiation Setting ..................... 5.23
Figure 5.22 Breaker Monitor Accumulates 10 Percent Wear.................................................................. 5.24
Figure 5.23 Breaker Monitor Accumulates 25 Percent Wear.................................................................. 5.25
Figure 5.24 Breaker Monitor Accumulates 50 Percent Wear.................................................................. 5.26
Figure 5.25 Breaker Monitor Accumulates 100 Percent Wear................................................................ 5.27
Figure 5.26 Input INxxx Connected to Trip Bus for Breaker Monitor Initiation.................................... 5.29
Figure 6.1 Front-Panel Setting Entry Example........................................................................................ 6.3
Figure 7.1 Simple Ethernet Network Configuration................................................................................ 7.3
Figure 7.2 Ethernet Network Configuration With Dual Redundant Connections (Failover Mode)........ 7.4
Figure 7.3 Ethernet Network Configuration With Ring Structure (Switched Mode).............................. 7.4
Figure 7.4 IRIG-B Input (Relay Terminals B01–B02)............................................................................ 7.6

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SEL-751 Relay Instruction Manual Date Code 20170927
List of Figures
Figure 7.5 IRIG-B Input Via EIA-232 Port 3 (SEL Communications Processor as Source).................. 7.7
Figure 7.6 IRIG-B Input Via EIA-232 Port 3 (SEL-2401/2404/2407 Time Source) .............................. 7.7
Figure 7.7 IRIG-B Input Via Fiber-Optic EIA-232 Port 2 (SEL-2030/2032 Time Source).................... 7.7
Figure 7.8 IRIG-B Input Via Fiber-Optic EIA-232 Port 2 (SEL-2401/2404/2407 Time Source)........... 7.8
Figure 7.9 EIA-232 DB-9 Connector Pin Numbers ................................................................................ 7.8
Figure 7.10 SEL Cable C234A—SEL-751 to DTE Device...................................................................... 7.9
Figure 7.11 SEL Cable C227A—SEL-751 to DTE Device...................................................................... 7.9
Figure 7.12 SEL Cable C222—SEL-751 to Modem.............................................................................. 7.10
Figure 7.13 SEL Cable C272A—SEL-751 to SEL Communications Processor
Without IRIG-B Signal..................................................................................................... 7.10
Figure 7.14 SEL Cable C273A—SEL-751 to SEL Communications Processor
With IRIG-B Signal.......................................................................................................... 7.10
Figure 7.15 SEL Cable C387—SEL-751 to SEL-3010 .......................................................................... 7.10
Figure 7.16 AFT Command Response .................................................................................................... 7.22
Figure 7.17 Breaker Monitor Report ....................................................................................................... 7.24
Figure 7.18 Breaker Wear Report ............................................................................................................ 7.25
Figure 7.19 Breaker Reset Response....................................................................................................... 7.25
Figure 7.20 CEV HIF Command Response ............................................................................................ 7.26
Figure 7.21 Ethernet Port (PORT 1) Status Report When NETMODE := PRP...................................... 7.30
Figure 7.22 Ethernet Port (PORT 1) Status Report When NETMODE := FIXED................................. 7.30
Figure 7.23 Ethernet Port (PORT 1) Status Report When NETMODE := FAILOVER, E61850 := Y,
and EGSE := Y ................................................................................................................. 7.31
Figure 7.24 Ethernet Port (PORT 1) Status Report When NETMODE := SWITCHED ........................ 7.31
Figure 7.25 Ethernet Port (PORT 1) Status Report for the Single Ethernet Port Option ........................ 7.32
Figure 7.26 GOOSE Command Response............................................................................................... 7.35
Figure 7.27 HSG Command Response.................................................................................................... 7.38
Figure 7.28 LOG H (HIF) Command Response...................................................................................... 7.41
Figure 7.29 PING Command Response................................................................................................... 7.45
Figure 7.30 SHOW Command Example ................................................................................................. 7.49
Figure 7.31 Typical Relay Output for STATUS S Command.................................................................. 7.52
Figure 7.32 THE Command Example ..................................................................................................... 7.56
Figure 7.33 CFG.TXT File ...................................................................................................................... 7.58
Figure 8.1 SEL-751 Front-Panel Models................................................................................................. 8.1
Figure 8.2 Front-Panel Overview ............................................................................................................ 8.2
Figure 8.3 Access Level Security Padlock Symbol ................................................................................. 8.4
Figure 8.4 Password Entry Screen........................................................................................................... 8.4
Figure 8.5 Front-Panel Pushbuttons......................................................................................................... 8.5
Figure 8.6 Main Menu ............................................................................................................................. 8.6
Figure 8.7 MAIN Menu and METER Submenu ..................................................................................... 8.6
Figure 8.8 METER Menu and ENERGY Submenu................................................................................ 8.6
Figure 8.9 Relay Response When Energy (or Max/Min, Demand, Peak Demand) Metering Is Reset... 8.7
Figure 8.10 Relay Response When No Analog Cards Are Installed......................................................... 8.7
Figure 8.11 Relay Response When No Math Variables Enabled .............................................................. 8.7
Figure 8.12 MAIN Menu and EVENTS Submenu.................................................................................... 8.7
Figure 8.13 EVENTS Menu and DISPLAY Submenu.............................................................................. 8.8
Figure 8.14 Relay Response When No Event Data Available................................................................... 8.8
Figure 8.15 Relay Response When Events Are Cleared ........................................................................... 8.8
Figure 8.16 MAIN Menu and TARGETS Submenu ................................................................................. 8.8
Figure 8.17 TARGETS Menu Navigation ................................................................................................. 8.9
Figure 8.18 MAIN Menu and CONTROL Submenu ................................................................................ 8.9
Figure 8.19 CONTROL Menu and OUTPUTS Submenu....................................................................... 8.10
Figure 8.20 CONTROL Menu and LOCAL BITS Submenu.................................................................. 8.10
Figure 8.21 MAIN Menu and SET/SHOW Submenu ............................................................................. 8.11
Figure 8.22 SET/SHOW Menu................................................................................................................ 8.12
Figure 8.23 MAIN Menu and Status Submenu ....................................................................................... 8.12
Figure 8.24 MAIN Menu and Breaker Submenu .................................................................................... 8.13
Figure 8.25 Factory Default Front-Panel LEDs....................................................................................... 8.13
Figure 8.26 Target Reset Pushbutton....................................................................................................... 8.15