Basler BE1-87T User manual

INSTRUCTION MANUAL
FOR
TRANSFORMER DIFFERENTIAL RELAY
BE1-87T
P0052-22
Serial No. XXXXXXXXXXXX
Style No. D2E A1J D1S0F
R
PUSH TO
ENERGIZE
OUTPUT
RU
TRANSFORMER DIFFERENTIAL
BE1-87T
Publication: 9171300990
Revision: R 09/07
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9171300990 Rev R BE1-87T Introduction i
INTRODUCTION
This instruction manual provides information about the operation and installation of the BE1-87T
Transformer Differential relay. To accomplish this, the following information is provided:
•General Information and Specifications
•Controls and Indicators
•Functional Description
•Installation
•Test Procedures
WARNING!
To avoid personal injury or equipment damage, only qualified personnel should
perform the procedures in this manual.
NOTE
Be sure that the relay is hard-wired to earth ground with no smaller than 12 AWG
copper wire attached to the ground terminal on the rear of the unit case. When
the relay is configured in a system with other devices, it is recommended to use a
separate lead to the ground bus from each unit.
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ii BE1-87T Introduction 9171300990 Rev R
First Printing: June 1990
Printed in USA
© 1990-1997, 1999-2000, 2003, 2005, 2007 Basler Electric, Highland Illinois 62249 USA
All Rights Reserved
September 2007
It is not the intention of this manual to cover all details and variations in equipment, nor does this manual
provide data for every possible contingency regarding installation or operation. The availability and design
of all features and options are subject to modification without notice. Should further information be
required, contact Basler Electric.
BASLER ELECTRIC
ROUTE 143, BOX 269
HIGHLAND IL 62249 USA
http://www.basler.com, [email protected]
PHONE [phone] FAX [phone]
CONFIDENTIAL INFORMATION
of Basler Electric, Highland Illinois, USA. It is loaned for confidential use, subject
to return on request, and with the mutual understanding that it will not be used in
any manner detrimental to the interest of Basler Electric.
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9171300990 Rev R BE1-87T Introduction iii
REVISION HISTORY
The following information provides a historical summary of the changes made to the BE1-87T instruction
manual (9171300990). Revisions are listed in reverse chronological order.
Manual
Revision and Date Change
R, 09/07 •Replaced magnetic type targets with electronic type targets.
•Updated power supply burden data and output contact ratings.
•Updated front panel illustrations to show laser graphics.
•Moved content of Section 6, Maintenance to Section 4, Installation.
•Added GOST-R certification to Section 1, General Information.
Q, 10/05 •In Section 1, General Information, Specifications, corrected values for
Maximum Current per Input for 1 Ampere CT Units.
•In Section 5, Test Procedures, corrected values inside CAUTION box
for 1 AMP CT on page 5-14.
P, 05/03 •Added a thumbscrew to the figure on the manual front cover.
•Added “not all styles” to the Power Supply Output heading on page 3-
4 as well as added “NOTE” and a text box around the second last
paragraph on page 3-4.
•Added the new thumbscrew to Figure 4-1 and changed the height
dimensions in Figure 4-2.
•Clarified the terminal numbers on Figure 4-6b.
•Added a shorting bar between terminals 6 & 7 in Figure 4-11.
•Added a shorting bar and normally open contact and normally closed
contact effecting terminals 1, 2, & 5 in Figure 4-12.
•Step 13 was corrected on pages 4-31 and 4-39 to include Rwin the
formulas.
•Values were changed to Table 5-4 under Option 1-0 for Unrestrained
Trip.
N, 09/00 •Corrected Table 1-3 to show power supply ranges.
•Changed instruction manual front cover, Figures 4-1, 4-3, and 4-5 to
show new unit case covers.
•Changed Figure 4-32 per markup.
M, 04/99 •Table 3-1 changed mid range nominal volt 125 Vac to 120 Vac.
•Corrected Figures 4-24, 4-31a, and A-3
•Corrected page 4-38, Step 10; added note to page 4-39, Step 13, and
corrected Steps 14 and 16.
•Page A-2, changed 3-Phase fault ratio current to 3-phase fault
current.
•Page A-3, corrected formulas for Figure A-3.
•Under Section 4, Procedure One, Verify CT Performance, changed
the procedure to the ANSI accuracy class method. This forced
changes in the following steps: 12, 13, 14, 16, 18, 20, and 21.
•Under Section 4, Procedure Two, Verify CT Performance, changed
the procedure to the ANSI accuracy class method. This forced
changes in the following steps: 12, 13, 14, and 16.
•Added ECO revision information to Table 8-1.
•Added Setting Note 7 (ANSI Accuracy Class Method) to Appendix A.
L, 05/97 •To delete the part number from the front cover of the manual.
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iv BE1-87T Introduction 9171300990 Rev R
Manual
Revision and Date Change
K, 03/97 •Deleted all references to Service Manual 9171300620.
•Changed the Title of Section 2 from “Controls and Indicators” to
“Human-Machine Interface”.
•Replaced the Power Supply Options paragraphs with a new Power
Supply paragraph explaining the new power supply design.
•Deleted Figure 3-2 and added Table 3-1, Wide Range Power Supply
Voltage Ranges.
•Changed Power Supply Status Output for Type G power supply on
the formerly page 3-6 (now page 3-4) from terminals 9 and 20 to
terminals 9 and 19.
•Added information to Section 4 to help the user understand the
procedures better.
•Deleted all NOTES FOR USERS OF SENSING INPUT TYPE F
RELAYS and added Section 7, Difference Data.
•Changed previous Section 7, Manual Change Information, to Section
8.
•Added an Appendix A to clarify the setting procedures.
•Added an index to help the user find information easier.
•Changed the format of the manual.
J, 01/96 •Deleted “Difference Data” (formerly Section 7) and included notes for
users of Type F relays.
•Moved all information regarding relay settings and checking relay
setting from Section 5, Testing and Setting, to Section 4, Installation.
Section 5 now contains information on test procedures.
•Combined 50 and 60 Hz Verification Tests.
•Various editorial changes.
•Reformatted instruction manual as Windows Help file for electronic
documentation.
I, 01/95 •Added outline (box) to Figure 5-8 to highlight the figure.
•Page 5-42, Step 5, changed, “should be less than 4.45” to, “must be
less than 4.45”.
•Added note to page 5-43, Step 10 and corrected the formula in Step
10.
•Page 5-45, Step 18, corrected formula and high side results; and
Step 19, changed last sentence from H (13 x tap) to S (21 x tap).
•Page 5-46, Steps 20 and 21, corrected figure references.
H, 12/94 •Page 1-6, changed Specification for Restrained Output, Pickup
Accuracy.
•Changed Section 5, Testing and Setting, Verification Tests (all
models): Steps 1, 4, 5, and 8; and Table 5-4.
•Page 5-50, Jumper Positions Wye-Delta 1, Step 3: Corrected Input 2
terminal identifications.
•Page 5-51, Jumper Positions Delta2-Delta2, Step 2: Corrected
verification statement.
G, 09/94 •Changed all sections to reflect new Option 1-1.
•Added to Section 5 four examples for testing relays to clarify test
procedures.
•Added to Section 5 one procedure for setting relays.
•Corrected typographical and illustration errors.
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9171300990 Rev R BE1-87T Introduction v
Manual
Revision and Date Change
F, 03/93 •Changed formula pages 5-4, 5-10, 5-16, and 5-22 from I = the square
root of K over t, to I = K over the square root of t.
E, 01/93 •Manual was revised to incorporate a revision in the relay that made
sensing input type F obsolete and included the 1 A, 60 hertz and 5 A,
50 hertz model relays.
•Section 5, Test Setup, diagrams were changed to clarify relay
connections.
•Added three relay Internal Connection diagrams.
•Changed unrestrained maximum time to trip, reference old Tables 5-4
and 5-8 (new Tables 5-4, 5-8, 5-12, and 5-16).
•Renamed Section 7, Manual Change Information to Section 8,
Manual Change Information and added new Section 7, Difference
Data to support BE1-87T relays with Sensing Input Type F.
D, 06/92 •Manual was revised to include the 1 A, 50 Hz model relay and
reformatted to a new Instruction Manual style.
•Additional connection diagrams were included in Section 4 and test
plug information was added to Section 6.
•Minor typographical errors were also corrected.
C, 03/91 •Table 5-1 was expanded and Figure 5-4 Test Setup illustration was
added.
•Miscellaneous editing.
B, 03/91 •Manual (with the exception of Section 2) was rewritten for ease of
use.
A, 06/90 •Figure 3-1 (Functional Block Diagram) corrected.
•Formula in caution note (formerly on p. 4-17, now on p. 5-2)
corrected.
•Miscellaneous editing.
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9171300990 Rev R BE1-87T Introduction vii
CONTENTS
SECTION 1 •GENERAL INFORMATION................................................................................................ 1-1
INTRODUCTION................................................................................................................................. 1-1
DESCRIPTION.................................................................................................................................... 1-1
APPLICATION .................................................................................................................................... 1-2
Single-Phase ................................................................................................................................ 1-2
Three-Phase................................................................................................................................. 1-2
Percentage Restraint.................................................................................................................... 1-2
Second-Harmonic Restraint ......................................................................................................... 1-2
Fifth-Harmonic Restraint............................................................................................................... 1-3
Unrestrained Trip.......................................................................................................................... 1-3
OPTIONS............................................................................................................................................ 1-3
Push-To-Energize Output Pushbuttons........................................................................................ 1-3
Auxiliary Output Contacts............................................................................................................. 1-3
Power Supply................................................................................................................................ 1-3
MODEL AND STYLE NUMBER.......................................................................................................... 1-4
Style Number Example................................................................................................................. 1-4
SPECIFICATIONS.............................................................................................................................. 1-5
Current Sensing Inputs................................................................................................................. 1-5
Current Sensing Burden............................................................................................................... 1-5
Tap Setting Control (Scaling) ....................................................................................................... 1-5
Restrained Output ........................................................................................................................ 1-5
Front Panel Setting %................................................................................................................... 1-6
Unrestrained Output..................................................................................................................... 1-6
Outputs......................................................................................................................................... 1-7
Target Indicators........................................................................................................................... 1-7
Harmonic Attenuation................................................................................................................... 1-7
Timing........................................................................................................................................... 1-7
Isolation ........................................................................................................................................ 1-9
Power Supply................................................................................................................................ 1-9
Surge Withstand Capability.......................................................................................................... 1-9
Radio Frequency Interference (RFI)............................................................................................. 1-9
UL Recognition............................................................................................................................. 1-9
GOST-R Certification.................................................................................................................... 1-9
Patent ........................................................................................................................................... 1-9
Shock............................................................................................................................................ 1-9
Vibration........................................................................................................................................ 1-9
Operating Temperature.............................................................................................................. 1-10
Storage Temperature ................................................................................................................. 1-10
Weight......................................................................................................................................... 1-10
Case Size ................................................................................................................................... 1-10
SECTION 2 •CONTROLS AND INDICATORS ....................................................................................... 2-1
LOCATION OF CONTROLS AND INDICATORS............................................................................... 2-1
SECTION 3 •FUNCTIONAL DESCRIPTION........................................................................................... 3-1
GENERAL........................................................................................................................................... 3-1
DESCRIPTION.................................................................................................................................... 3-1
Current Transformers................................................................................................................... 3-1
Scaling.......................................................................................................................................... 3-1
Summing....................................................................................................................................... 3-1
30°Internal Phase Shift (Three-Phase Relays ONLY) ................................................................ 3-1
Restrained Trip Output................................................................................................................. 3-3
Unrestrained Trip Output.............................................................................................................. 3-3
Auxiliary Relay Option.................................................................................................................. 3-4
Power Supply................................................................................................................................ 3-4
Power Supply Status Output (Optional) ....................................................................................... 3-4
Target Indicators (Optional).......................................................................................................... 3-4
% of Trip ....................................................................................................................................... 3-5
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viii BE1-87T Introduction 9171300990 Rev R
SECTION 4 •INSTALLATION.................................................................................................................. 4-1
GENERAL........................................................................................................................................... 4-1
RELAY OPERATING PRECAUTIONS............................................................................................... 4-1
MOUNTING......................................................................................................................................... 4-1
DIELECTRIC TEST............................................................................................................................. 4-9
CONNECTIONS.................................................................................................................................. 4-9
RELAY DISASSEMBLY.................................................................................................................... 4-17
Precautions................................................................................................................................. 4-17
Circuit Board Removal Procedure.............................................................................................. 4-17
DISABLING UNUSED INPUTS......................................................................................................... 4-18
Single-Phase Units..................................................................................................................... 4-20
Three-Phase Units...................................................................................................................... 4-20
SENSING CONNECTION DIAGRAMS ............................................................................................ 4-20
Single-Phase Input Sensing Connections.................................................................................. 4-20
Three-Phase Input Sensing Connections................................................................................... 4-20
SETTING THE BE1-87T................................................................................................................... 4-33
Method........................................................................................................................................ 4-33
Procedure One ........................................................................................................................... 4-33
Procedure Two ........................................................................................................................... 4-42
CHECKING THE RELAY SETTINGS AND SYSTEM INPUTS........................................................ 4-49
MAINTENANCE................................................................................................................................ 4-50
STORAGE......................................................................................................................................... 4-50
TEST PLUG ...................................................................................................................................... 4-50
SECTION 5 •TEST PROCEDURES ........................................................................................................ 5-1
OVERVIEW......................................................................................................................................... 5-1
EQUIPMENT REQUIRED................................................................................................................... 5-1
Verification Tests.......................................................................................................................... 5-1
RESTRAINED PICKUP TESTING EXAMPLES ................................................................................. 5-2
Increasing One Input from Balance.............................................................................................. 5-2
Decreasing One Input from Balance ............................................................................................ 5-5
TEST SETUP DIAGRAMS.................................................................................................................. 5-7
VERIFICATION TESTS: 5 AMP CT, 50 OR 60 HZ UNITS ................................................................ 5-9
Restrained Pickup Level Verification............................................................................................ 5-9
Input (or Tap) Switch Verification ............................................................................................... 5-10
Unrestrained Pickup Verification ................................................................................................ 5-11
Second-Harmonic Restraint Verification .................................................................................... 5-11
Fifth-Harmonic Restraint Verification.......................................................................................... 5-12
Response Time Verification........................................................................................................ 5-13
VERIFICATION TESTS: 1 AMP CT, 50 OR 60 HZ UNITS .............................................................. 5-14
Restrained Pickup Level Verification.......................................................................................... 5-14
Input (or Tap) Switch Verification ............................................................................................... 5-15
Unrestrained Pickup Verification ................................................................................................ 5-16
Second-Harmonic Restraint Verification .................................................................................... 5-16
Fifth-Harmonic Restraint Verification.......................................................................................... 5-17
Response Time Verification........................................................................................................ 5-18
OPERATIONAL TEST PROCEDURES............................................................................................ 5-19
Restrained Pickup....................................................................................................................... 5-19
Unrestrained Pickup ................................................................................................................... 5-19
Second-Harmonic Inhibit............................................................................................................ 5-19
Fifth-Harmonic Inhibit ................................................................................................................. 5-20
TESTING THREE-PHASE UNITS WITHOUT CHANGING JUMPERS ........................................... 5-20
Jumper Positions Wye-Wye ....................................................................................................... 5-21
Jumper Positions Wye-Delta1.................................................................................................... 5-21
Jumper Positions Wye-Delta2.................................................................................................... 5-22
Jumper Positions Delta1-Delta1................................................................................................. 5-22
Jumper Positions Delta2-Delta2................................................................................................. 5-23
Jumper Positions Delta1-Delta2................................................................................................. 5-23
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9171300990 Rev R BE1-87T Introduction ix
SECTION 6 •DIFFERENCE DATA.......................................................................................................... 6-1
GENERAL........................................................................................................................................... 6-1
DIFFERENCES................................................................................................................................... 6-1
COMPATIBILITY................................................................................................................................. 6-1
CONNECTIONS.................................................................................................................................. 6-1
APPENDIX A •SETTING NOTES............................................................................................................A-1
INTRODUCTION.................................................................................................................................A-1
SETTING NOTE 1...............................................................................................................................A-1
SETTING NOTE 2...............................................................................................................................A-2
SETTING NOTE 3...............................................................................................................................A-3
SETTING NOTE 4...............................................................................................................................A-4
SETTING NOTE 5...............................................................................................................................A-4
Slope Margin.................................................................................................................................A-4
SETTING NOTE 6...............................................................................................................................A-6
Inrush vs. Unrestraint Tap............................................................................................................A-6
SETTING NOT 7.................................................................................................................................A-7
CT Performance Evaluation: Saturation Error..............................................................................A-7
Saturation Factor Defined from the ANSI C Classification...........................................................A-7
Saturation Factor Defined from the CT Excitation Curve.............................................................A-8
Saturation Factor Definitions Compared......................................................................................A-8
Conclusion..................................................................................................................................A-10
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9171300990 Rev R BE1-87T General Information 1-1
SECTION 1 • GENERAL INFORMATION
INTRODUCTION
These instructions provide information concerning the operation and installation of BE1-87T Transformer
Differential Relays. To accomplish this, the following is provided:
•Specifications
•Functional characteristics
•Mounting information
•Setting procedures and examples
WARNING!
To avoid personal injury or equipment damage, only qualified personnel should perform
the procedures presented in these instructions.
These instructions may be used in place of all earlier editions. For change information, see Section 8.
NOTE FOR USERS OF SENSING INPUT TYPE F RELAYS
Users of BE1-87T relays with Sensing Input Type F (three-phases three inputs per
phase) will find Difference Data in Section 6 of this manual that describes features
specific to these relays. The three-phase, three inputs per phase design, previously
available as Sensing Input Type F, has been modified and is now available as Sensing
Input Type G. Due to differences in components and output terminal connections, Type G
relays are not compatible with earlier versions of the BE1-87T with Sensing Input Type F.
There are also differences in the output connections as described in Section 6,
Difference Data.
DESCRIPTION
BE1-87T Transformer Differential Relays provide primary protection for power transformers and are
available in either Single-Phase or Three-Phase configurations. The solid-state BE1-87T compares the
currents entering and leaving the protected transformer. If a fault is detected, the relay initiates a trip
signal to isolate the power transformer. This limits damage to the transformer and minimizes the impact
on the power system.
BE1-87T relays use three types of restraint:
•Percentage of through-current
•Second harmonic
•Fifth harmonic
Selectivity in differential relaying is based on the ability to distinguish between internal and external faults.
This is achieved by comparing the currents into and out of a power transformer. Comparing these
currents often requires more than two inputs. For example:
•Power transformers may have a significant portion (greater than 10 %) of the current flowing in a
third or tertiary winding.
•Power transformers can have multiple breakers for a given winding (e.g., ring bus or breaker-
and-a-half bus).
BE1-87T relays are available with up to five restraint inputs for the single-phase unit and up to three
restraint inputs per phase for the three-phase unit.
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1-2 BE1-87T General Information 9171300990 Rev R
APPLICATION
In general, power transformers have different values of current flowing through their primary, secondary,
and tertiary windings. These currents have specific phase relationships depending upon the connections
of the individual windings (e.g., wye/delta). As inputs to a differential relay, these currents must be
compensated or scaled so that the relay can compare the inputs and determine when an unbalance
exists. Under ideal operating conditions, the scaled vector sum of these currents is zero.
Because it is practically impossible to match the magnitudes of these detected currents from the various
power windings using standard CT ratios, the currents are matched within the relay by scaling each of the
applied currents by an appropriate factor called a Tap Setting. This is set by means of the front panel
INPUT dials. By selecting suitable tap ratios, the applied currents are scaled within the relay to achieve
the desired balance for normal operating conditions. BE1-87T relays offer a range of available tap
settings for inputs between 0.4 A to 1.78 A (Sensing Input Range Options 2 and 4 for a 1 A CT) or 2.0 to
8.9 A (Sensing Input Range Options 1 and 3 for a 5A CT). These settings are independently adjustable in
increments of 0.02 A for Sensing Input Range Options 2 and 4, or 0.1 A for Sensing Input Range Options
1 and 3. These small increments allow more precise scaling of the applied currents and usually eliminate
the need for installing auxiliary ratio-matching CTs.
Single-Phase
BE1-87T Single-Phase relays require phase angle compensation to be accomplished externally by proper
connection of the system CT secondaries. A wye/delta transformer requires that the CT secondaries be
connected in delta for the wye winding and in wye for the delta winding. This type of connection also
eliminates the zero-sequence component of current which could cause a false trip (operation) during
external ground fault conditions on the wye system.
Three-Phase
BE1-87T Three-Phase relays can provide zero-sequence filtering and compensation for phase shifts
introduced by the connections of the power transformer. This 30° Phase Shift compensation (either ±30°
or no compensation) is field selectable. Additionally, this feature allows sharing the transformer differential
relay CTs with other relays or instrumentation.
BE1-87T relays use the highest input current (in per unit values) to operate on maximum restraint. The
relay does not have a conventional operate winding in the internal magnetics. Operating current is
developed within the electronics of the relay.
Percentage Restraint
A primary concern in differential relay applications is security against high current levels caused by faults
outside the protected zone. Inevitable differences in the saturation characteristics between current
transformers require a compensating decrease in relay sensitivity. It is also necessary to be able to adjust
the sensitivity to compensate for transformer voltage taps or CT mismatches. This is accomplished by
providing a restraint factor proportional to the current flowing through the protected zone (through-
current).
BE1-87T relays maintain sensitivity at a specified ratio of trip current to through current. This ratio,
generally referred to as slope, is front-panel adjustable in 5 % increments from 15 to 60 %.
Second-Harmonic Restraint
Magnetizing inrush current presents another problem unique to transformer differential relays. Relays
must be capable of detecting the small differences in current caused by the shorting of a limited number
of turns, yet remain secure against the occurrence of magnetizing currents many times the transformer
rating (as seen at one set of terminals).
Although magnetizing inrush is usually associated with the energizing of the transformer, any abrupt
change in the energizing voltage may produce this phenomenon. Common causes are the transients
generated during the onset, evolution and removal of external faults. Desensitizing the relay only during
energization is therefore insufficient.
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9171300990 Rev R BE1-87T General Information 1-3
Magnetizing inrush produces an offset sine wave rich in all harmonics. BE1-87T relays use the second
harmonic to restrain operation because it predominates and because it does not occur in significant
magnitude or duration at other times.
Three-phase BE1-87T relays use second-harmonic sharing. The second-harmonic content of all three
phases is summed together to derive the restraint for each phase. As a result, the second-harmonic
inhibit range and the associated factory setting, is higher than on single-phase relays.
Fifth-Harmonic Restraint
Power transformer overexcitation causes additional exciting current to flow into one set of terminals. This
presents an apparent differential (or operating) current not attributable to an internal fault. Although
potentially damaging, overexcitation is not an internal fault and, therefore, is not an appropriate condition
for transformer differential relay operation. One of the principal components in the complex waveform
produced during overexcitation is the fifth harmonic. BE1-87T relays use fifth-harmonic restraint to inhibit
the differential relay operation.
Unrestrained Trip
Severe internal transformer faults may cause CT saturation. Under such circumstances, harmonic-
restraint transformer differential relays may fail to trip because of the extremely high harmonic content in
the waveform. Lack of operation can result in severe transformer damage.
BE1-87T relays provide an independent unrestrained tripping function. When set above the possible
inrush current magnitude, this function provides high-speed protection for the most severe internal faults.
OPTIONS
Push-To-Energize Output Pushbuttons
Two PUSH-TO-ENERGIZE OUTPUT switches are available as a means to verify external output wiring
without the inconvenience of having to test the entire relay. Option 2-S provides a small pushbutton
switch for each isolated output function (Restrained and Unrestrained) and may be actuated by inserting
a thin, non-conducting rod through access holes in the front panel. Refer to Figure 2-1 through 2-4 for
location.
Appropriate power must be applied to Power Supply terminals 3 and 4 (shown in Figures 4-7 through 4-
10) for these pushbuttons to operate the output relays. However, it is not necessary to apply currents to
the sensing inputs of the relay for these switches to function.
Auxiliary Output Contacts
Three types of auxiliary output contacts are available: Normally open, normally closed and SPDT. The
contacts can be made to respond to a restrained trip, an unrestrained trip or both. Refer to the
Functional Description: Auxiliary Relay Option for further information.
Power Supply
Various power supply options are available to allow the BE1-87T to be used with standard supply
voltages. See the Style Number Identification Chart, Figure 1-1, for details.
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1-4 BE1-87T General Information 9171300990 Rev R
MODEL AND STYLE NUMBER
The electrical characteristics and operational features of the BE1-87T Transformer Differential Relay are
defined by a combination of letters and numbers that make up its Style Number. The Model Number
together with the Style Number, describe the options included in a specific device and appear on the front
panel, drawout cradle and inside the case assembly.
Upon receipt of a relay, be sure to check the Style Number against the requisition and the packing list to
ensure that they agree.
Style Number Example
The Style Number Identification Chart (Figure 1-1) defines the electrical characteristics and operational
features included in BE1-87T relays. For example, if the Style Number were G1E-A1Y-D1S0F, the device
would have the following:
BE1-87T Model Number (designates the relay as a Basler Electric, Class 100, Transformer Differential
Relay)
G Three-phase sensing with three inputs per phase
1 2.0 to 8.9 A Sensing Range at 60 Hz
E One unrestrained output contact and one restrained output contact
A1 No intentional delay in the outputs
Y 48/125 Vdc switchable
D Current operated targets
1 Percent IOP display and high-speed trip
S Push-to-Energize outputs
0 No auxiliary output
F Semi-flush mounting
Figure 1-1. Style Number Identification Chart
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9171300990 Rev R BE1-87T General Information 1-5
SPECIFICATIONS
The BE1-87T relay is available in either single-phase or three-phase configurations and with the following
features and capabilities.
Current Sensing Inputs The unit is designed to operate from the secondary of current
transformers rated at either 1 A or 5 A. Frequency range is ±5 Hz of
nominal.
Maximum Current Per Input
1 Ampere CT Units 4 A continuous; 50 A or 50 X tap (whichever is less) for 1 second.
5 Ampere CT Units 20 A continuous; 250 A or 50 X tap (whichever is less) for 1
second.
For ratings other than one second, the rating may be calculated as:
I
K
t
=
Where:
t is the time (in seconds) that the current flows
K = 50 A or 50 X tap, whichever is less (1 Amp CT Units), or
K = 250 A or 50 X tap, whichever is less (5 Amp CT Models)
Current Sensing Burden Less than 0.02 ohm per phase.
Tap Setting Control (Scaling) Front panel rotary switches, labeled INPUT, permit scaling the
sensed input current (or tap setting) over the range of:
1 Ampere CT Units 0 . 4 to 1 . 78 in 0 . 02 A increments.
5 Ampere CT Units 2 . 0 to 8 . 9 A, in 0 . 1 A increments.
Restrained Output
Pickup Range Front panel thumbwheel switches adjust pickup of the restrained
output as a percentage of the through current. The range is 15 to
60 % of the operating current in 5 % increments.
Pickup Accuracy ±6 % of pickup ±100 mA (5 Ampere Units) or ±20 mA(1 Ampere
units).
Minimum Pickup 0.35 ±6 % of tap setting. Refer to Table 1-1 and Figure 1-2. Table
1-1 provides calculated intersection points of the slope
characteristic and the minimum pickup (in multiples of tap) as
shown in Figure 1-2. The calculation was derived from the formula:
M
aximum
I
M
inimum Pickup
P
ercent o
f
Slope
R
estrain
t
=
For example:
M
inimum Picku
p
P
ercent o
f
Slo
p
e==
0.35
20 1.75 %
The relay operates when the per unit difference current (operating
current) is above the 0.35 pu or the slope line in Figure 1-2.
Calculation examples are found in Section 5.
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1-6 BE1-87T General Information 9171300990 Rev R
Table 1-1. Multiples of Tap
Front Panel Setting % 15 20 25 30 35 40 45 50 55 60
Maximum Restraint
Current At Minimum
Pickup In Multiples of
Tap
2.33 1.75 1.40 1.17 1.00 0.875 0.778 0.700 0.636 0.583
Figure 1-2. Percentage Restraint Characteristic
Second-Harmonic Restraint Inhibit of the restrained output occurs when the second-
harmonic component exceeds a pickup setting, which is
internally adjustable over the range of 8 % to 15 % of the
operating current for single-phase Units or 11 to 27 % for
three-phase units. The factory setting is 12 % for single-
phase units and 18 % for three-phase units.
Fifth-Harmonic Restraint Inhibit of the restrained output occurs when the fifth-harmonic
component exceeds a pickup setting which has an internally
adjustable range of 25 to 45 % of the operating current. The
factory setting is 35 %.
Unrestrained Output
Pickup Range Front panel thumbwheel switches adjust the pickup point of
the unrestrained output over a range of 6 to 21 times the tap
setting in increments of 1 x Tap.
Pickup Accuracy ±3 % of the front panel setting.
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9171300990 Rev R BE1-87T General Information 1-7
Outputs Output contacts are rated as follows.
Resistive
120/240 Vac Make 30 A for 0.2 seconds, carry 7 A continuously and break
7 A.
250 Vdc Make and carry 30 A for 0.2 seconds, carry 7 A continuously
and break 0.3 A.
500 Vdc Make and carry 15 A for 0.2 seconds, carry 7 A continuously
and break 0.1 A.
Inductive
120/240 Vac, 125/250 Vdc Make and carry 30 A for 0.2 seconds, carry 7 A continuously
and break 0.3 A, (L/R = 0.04).
Target Indicators Target indicators may be either internally-operated or current-
operated (operated by a minimum of 0.2 A through the output
trip circuit). When the target is current-operated, the
associated output circuit must be limited to 30 A for 0.2
seconds, 7 A for 2 minutes and 3 A continuously.
Single-Phase Units Either an internally-operated or a current-operated target is
supplied (as selected by the Style Number) for each trip
output (i.e., the restrained and the unrestrained functions).
Three-Phase Units Either internally operated or current operated targets (as
selected) indicate the function (restrained or unrestrained)
that caused the trip, and the tripped phase (A, B, C).
Harmonic Attenuation Refer to Table 1-2.
Table 1-2. Harmonic Attenuation
Parameter
(50 Or 60 Hz Models) Minimum Attenuation at Indicated Fundamental
50/60 Hz 100/120 Hz 150/180 Hz 250/300 Hz 500 Hz
Through Current 0 0 0 0 12 dB
Operating Current 0 0 0 0 12 dB
2nd Harmonic Restraint 12 dB 0 12 dB 12 dB 12 dB
5th Harmonic Restraint 12 dB 12 dB 12 dB 0 12 dB
Timing
(For 60 Hz units only) Refer to Figure 1-3 for Unrestrained Response Times and
Figure 1-4 for Restrained Response Times.
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1-8 BE1-87T General Information 9171300990 Rev R
Figure 1-3. Unrestrained Response Times
Figure 1-4. Restrained Response Times
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