Thytronic NA20 User manual

NA20 - Manual - 04 - 2022
MANUAL
NA20
PHASE, NEGATIVE SEQUENCE,
RESIDUAL OVERCURRENT, THERMAL IMAGE
PROTECTION RELAY

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NA20 - Manual - 04 - 2022
TABLE OF CONTENTSTABLE OF CONTENTS
1 INTRODUCTION 5
Scope and liability...........................................................................................................................................................................................5
Applicability......................................................................................................................................................................................................5
Conformity ........................................................................................................................................................................................................5
Copyright...........................................................................................................................................................................................................5
Warranty...........................................................................................................................................................................................................5
Safety recommendations...............................................................................................................................................................................5
Insulation tests ................................................................................................................................................................................................5
Product identification .....................................................................................................................................................................................6
Environment .....................................................................................................................................................................................................6
Graphical conventions ...................................................................................................................................................................................6
Glossary/definitions........................................................................................................................................................................................6
2 GENERAL 10
Preface........................................................................................................................................................................................................... 10
Photo .............................................................................................................................................................................................................. 10
Main features.................................................................................................................................................................................................11
3 TECHNICAL DATA 12
3.1 GENERAL............................................................................................................................................................................................................12
Product standard for measuring relays.....................................................................................................................................................12
Mechanical data ...........................................................................................................................................................................................12
Insulation ........................................................................................................................................................................................................12
Voltage dip and interruption........................................................................................................................................................................12
EMC tests for interference immunity.........................................................................................................................................................12
Emission......................................................................................................................................................................................................... 13
Mechanical tests.......................................................................................................................................................................................... 13
Climatic tests................................................................................................................................................................................................. 13
Safety ............................................................................................................................................................................................................. 13
Certifications................................................................................................................................................................................................. 13
3.2 INPUT CIRCUITS ...............................................................................................................................................................................................14
Auxiliary power supply Uaux ......................................................................................................................................................................14
Phase current input circuits........................................................................................................................................................................14
Residual current input circuit......................................................................................................................................................................14
Binary input circuits......................................................................................................................................................................................14
Block input (Logic selectivity).....................................................................................................................................................................14
3.3 OUTPUT CIRCUITS............................................................................................................................................................................................14
Relays..............................................................................................................................................................................................................14
Block output (Logic selectivity)...................................................................................................................................................................14
3.4 MMI.....................................................................................................................................................................................................................15
3.5 COMMUNICATION INTERFACES ...................................................................................................................................................................15
Local port........................................................................................................................................................................................................15
Remote ports..................................................................................................................................................................................................15
3.6 GENERAL SETTINGS ........................................................................................................................................................................................16
3.7 PROTECTIVE FUNCTIONS ...............................................................................................................................................................................16
Base current - IB...........................................................................................................................................................................................16
Thermal protection with Pt100 probes - 26 ...............................................................................................................................................16
Undercurrent - 37..........................................................................................................................................................................................16
Negative sequence overcurrent - 46.........................................................................................................................................................16
Negative sequence / positive sequence current ratio - I2 / I1..............................................................................................................17
Thermal image - 49....................................................................................................................................................................................... 18
Phase overcurrent - 50/51........................................................................................................................................................................... 18
Residual overcurrent - 50N/51N ................................................................................................................................................................ 19
Breaker failure - BF...................................................................................................................................................................................... 20
3.8 CONTROL AND MONITORING........................................................................................................................................................................21
Second harmonic restraint - 2ndh-REST...................................................................................................................................................21
Trip Circuit Supervision - 74TCS..................................................................................................................................................................21
Selective block - BLOCK2 ............................................................................................................................................................................21
Circuit Breaker supervision.........................................................................................................................................................................21
CT supervision - 74CT ...................................................................................................................................................................................21
Pilot wire diagnostic .....................................................................................................................................................................................21
Demand measures........................................................................................................................................................................................21
Oscillography (DFR) ......................................................................................................................................................................................22
PLC (Programmable Logic Controller) .......................................................................................................................................................22

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3.9 METERING......................................................................................................................................................................................................... 23
Accuracy (type tests)................................................................................................................................................................................... 23
Measures....................................................................................................................................................................................................... 23
4 FUNCTION CHARACTERISTICS 24
4.1 HARDWARE DESCRIPTION.............................................................................................................................................................................24
Power supply board......................................................................................................................................................................................25
CPU board.......................................................................................................................................................................................................25
Input board .....................................................................................................................................................................................................25
MMI (keyboard, LED and display) ..............................................................................................................................................................25
4.2 SOFTWARE DESCRIPTION ..............................................................................................................................................................................26
Base software................................................................................................................................................................................................26
Real-time operating system.........................................................................................................................................................................26
Task..................................................................................................................................................................................................................26
Drivers.............................................................................................................................................................................................................27
Application Software....................................................................................................................................................................................27
Data Base.......................................................................................................................................................................................................27
Self test (Application) ...................................................................................................................................................................................27
Development tools (Builder)........................................................................................................................................................................27
4.3 I/O DESCRIPTION............................................................................................................................................................................................. 28
Metering inputs ............................................................................................................................................................................................ 28
Signal processing......................................................................................................................................................................................... 28
Conventions....................................................................................................................................................................................................31
Use of measured values...............................................................................................................................................................................32
Binary inputs ................................................................................................................................................................................................. 33
Output relays................................................................................................................................................................................................. 38
LED indicators............................................................................................................................................................................................... 40
Communication interfaces...........................................................................................................................................................................42
4.4 PROTECTIVE ELEMENTS ................................................................................................................................................................................ 43
Rated values.................................................................................................................................................................................................. 43
Thermal protection with RTD thermometric probes - 26 ........................................................................................................................45
Undercurrent - 37..........................................................................................................................................................................................47
Negative sequence overcurrent - 46........................................................................................................................................................ 49
Negative sequence current / positive sequence current ratio - I2/I1..................................................................................................56
Thermal image - 49....................................................................................................................................................................................... 58
Phase overcurrent - 50/51........................................................................................................................................................................... 69
Residual overcurrent - 50N/51N ................................................................................................................................................................ 79
Breaker failure - BF...................................................................................................................................................................................... 89
4.5 CONTROL AND MONITORING........................................................................................................................................................................91
Logical block - BLOCK1................................................................................................................................................................................91
Selective block -BLOCK2 ............................................................................................................................................................................ 93
Remote tripping ............................................................................................................................................................................................ 98
Frequency tracking...................................................................................................................................................................................... 99
Second Harmonic Restraint - 2ndh-REST .............................................................................................................................................. 100
Cold Load Pickup - CLP ..............................................................................................................................................................................101
CT supervision - 74CT ................................................................................................................................................................................ 103
Trip circuit supervision - 74TCS.................................................................................................................................................................104
Circuit breaker supervision .......................................................................................................................................................................107
Demand measures..................................................................................................................................................................................... 110
Oscillography ............................................................................................................................................................................................. 110
5 MEASURES, LOGIC STATES AND COUNTERS 111
Measures......................................................................................................................................................................................................111
Protection .....................................................................................................................................................................................................111
Delayed inputs.............................................................................................................................................................................................111
Internal states..............................................................................................................................................................................................111
Relays............................................................................................................................................................................................................112
Counters........................................................................................................................................................................................................112
Self test .........................................................................................................................................................................................................112
Pilot wire diagnostic .................................................................................................................................................................................. 113
Selective Block - BLOCK2......................................................................................................................................................................... 113
Fault recording - SFR................................................................................................................................................................................. 113
Event recording - SER................................................................................................................................................................................ 113
Oscillography - DFR ....................................................................................................................................................................................114

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6 INSTALLATION 116
6.1 PACKAGING.....................................................................................................................................................................................................116
6.2 MOUNTING......................................................................................................................................................................................................116
6.3 ELECTRICAL CONNECTIONS ....................................................................................................................................................................... 120
6.4 NOMINAL CURRENT InAND IEn SETTING ............................................................................................................................................... 130
6.5 LED ALLOCATION............................................................................................................................................................................................134
6.6 FINAL OPERATIONS .......................................................................................................................................................................................134
7 PROGRAMMING AND SETTINGS 135
7.1 SW ThyVisor ....................................................................................................................................................................................................135
ThyVisor installation....................................................................................................................................................................................135
ThyVisor use.................................................................................................................................................................................................135
7.2 MMI (Man Machine Interface) ....................................................................................................................................................................136
Reading variables (READ)..........................................................................................................................................................................136
Setting modifying (SET) ..............................................................................................................................................................................136
TEST.............................................................................................................................................................................................................. 138
COMMUNICATION..................................................................................................................................................................................... 138
Circuit breaker commands ....................................................................................................................................................................... 139
Enable / block changes via keyboard - Password................................................................................................................................ 139
7.3 MODULES MANAGEMENT .......................................................................................................................................................................... 140
7.4 MAINTENANCE...............................................................................................................................................................................................141
7.5 REPAIR..............................................................................................................................................................................................................141
7.6 PACKAGING.....................................................................................................................................................................................................141
8 APPENDIX 142
8.1 APPENDIX A1 - Inverse time IEC curves ...................................................................................................................................................142
Mathematical formula................................................................................................................................................................................142
Negative sequence overcurrent 46 - Standard inverse time curve (IEC 60255-3/BS142 type A) ................................................ 143
Negative sequence overcurrent 46 - Very inverse time curve (IEC 60255-3/BS142 type B)..........................................................144
Negative sequence overcurrent 46 - Extremely inverse time curve (IEC 60255-3/BS142 type C) ................................................145
Phase overcurrent 50/51 - Standard inverse time curve (IEC 60255-3/BS142 type A)....................................................................146
Phase overcurrent 50/51 - Very inverse time curve (IEC 60255-3/BS142 type B) ............................................................................147
Phase overcurrent 50/51 - Extremely inverse time curve (IEC 60255-3/BS142 type C).................................................................. 148
Phase overcurrent 50/51 - long time inverse curve (IEC BS B LI)..................................................................................................... 149
Residual overcurrent 50N/51N - Standard inverse time curve (IEC 60255-3/BS142 type A) ........................................................ 150
Residual overcurrent 50N/51N - Very inverse time curve (IEC 60255-3/BS142 type B)..................................................................151
Residual overcurrent 50N/51N - Extremely inverse time curve (IEC 60255-3/BS142 type C) ........................................................152
Residual overcurrent 50N/51N - long time inverse curve (IEC BS B LI)........................................................................................... 153
8.2 APPENDIX A2 - Inverse time ANSI/IEEE curves .......................................................................................................................................154
Mathematical formula................................................................................................................................................................................154
Negative sequence overcurrent 461 - Moderately inverse time curve (ANSI/IEEE type MI).......................................................155
Negative sequence overcurrent 46 - Very inverse time curve (ANSI/IEEE type VI).......................................................................156
Negative sequence overcurrent 46 - Extremely inverse time curve (ANSI/IEEE type EI)..............................................................157
Phase overcurrent 50/51 - Moderately inverse time curve (ANSI/IEEE type MI)........................................................................... 158
Phase overcurrent 50/51 - Very inverse time curve (ANSI/IEEE type VI) ........................................................................................ 159
Phase overcurrent 50/51 - Extremely inverse time curve (ANSI/IEEE type EI)............................................................................... 160
Residual overcurrent 50N/51N - Moderately inverse time curve (ANSI/IEEE type MI) .................................................................161
Residual overcurrent 50N/51N - Very inverse time curve (ANSI/IEEE type VI) ...............................................................................162
Residual overcurrent 50N/51N - Extremely inverse time curve (ANSI/IEEE type EI)..................................................................... 163
8.3 APPENDIX A3 - Inverse time - RECTIFIER, I2t and EM curves ................................................................................................................164
Mathematical formula................................................................................................................................................................................164
Phase overcurrent 50/51 - Rectifier curves............................................................................................................................................165
Negative sequence overcurrent 46 - I2t inverse curves (I2t=K) .........................................................................................................166
Phase overcurrent 50/51 - I2t inverse curves (I2t=K) ............................................................................................................................167
Negative sequence overcurrent 46 - Electromechanical inverse curves (EM) .............................................................................. 168
Phase overcurrent 50/51 - Electromechanical inverse curves (EM)................................................................................................. 169
Residual overcurrent 50N/51N - Electromechanical inverse curves (EM)....................................................................................... 170
8.4 APPENDIX B1 - I/O Diagram .........................................................................................................................................................................171
8.5 APPENDIX B2 - Interfaces ............................................................................................................................................................................172
8.6 APPENDIX B3- Connection diagrams ........................................................................................................................................................ 173
8.7 APPENDIX C - Dimensions............................................................................................................................................................................176
8.8 APPENDIX D - Setting table..........................................................................................................................................................................177
8.9 APPENDIX E - EC Declaration of conformity............................................................................................................................................. 208

INTRODUCTION 5
NA20 - Manual - 04 - 2022
1 INTRODUCTION1 INTRODUCTION
Scope and liability
This document describes the functions, the technical data of NA20 devices; instructions for mount-
ing, setting and commissioning are included.
This manual has been checked out, however, deviations from the description cannot be completely
ruled out, so that no liability in a legal sense for correctness and completeness of the information or
from any damage that might result from its use is formally disclaimed.
The information given in this document is reviewed regularly; any corrections and integration will be
included in subsequent editions that are identified by the date of revision.
We appreciate any suggestions for improvement.
We reserve the right to make technical improvements without notice.
Applicability
This manual is valid for NA20 devices with firmware version 2.70 and following.
Conformity
The product complies with the CEE directives:
• EMC Council Directives: 2014/30/EC
• Low voltage Directives: 2014/35/EC
Copyright
All right reserved; It is forbidden to copy, modify or store material (document and sw) protected by
copyright without Thytronic consent.
Warranty
Thytronic warrants devices against defects in materials and workmanship under normal use for a
period of ONE (1) YEAR from the date of retail purchase by the original end-user purchaser (“War-
ranty Period”).
Safety recommendations
The warming contained in this document are all-important for safety; special attention must be paid
to the following symbols:
Installation and commissioning must be carried out by qualified person; Thytronic assumes no re-
sponsibility for damages caused from improper use that does not comply all warning and caution in
this manual.
In particular the following requirements must be met:
• Remove power before opening it.
• Verify the voltage absence by means suitable instrumentation on relay connections; attention must
be paid to all circuits supplied by external sources (binary input, CT, etc...)
• Care must be taken when handling metal parts.
Insulation tests
After insulation tests, hazardous voltages (capacitor charges,...) may be arise; it is advisable to grad-
ually reduce the test voltage avoiding to erase it abruptly.
DANGER Death, severe personal injury or substantial property damage will result if proper precautions
are not taken
WARNING Death, severe personal injury or substantial property damage can result if proper precautions
are not taken.
CAUTION Minor personal injury or property damage can result if proper precautions are not taken
CAUTION
Settings must be established on the basis of a coordination study.
Numerical values inside examples have educational purpose only; they don’t be used, in no way,
for actual applications.

INTRODUCTION 6
NA20 - Manual - 04 - 2022
Product identification
Each device is equipped with:
• Identification label installed on the front side with following informations: code number, phase and
residual nominal currents, auxiliary voltage range and CE mark:
• Test label with following informations: data, serial number and test operator signature.
Environment
The NA20 device must be employed according to the environment conditions shown (see technical
data).
In case of different environment conditions, appropriate provisions must be provided (conditioning
system, humidity control, etc...).
If contaminants are present (dust, corrosive substances, etc...), filters must be provided.
Graphical conventions
The CEI/IEC and ANSI symbols is employed where possible:
e.g.: 51 = ANSI code concerning the overcurrent element.
Following text formats are used:
The ThyVisor[1] menu:
Phase overcurrent -50/51
The parameter description (measures, thresholds, operate time,...) and related value:
I> element
    Denitetime
I>def
The display messages (MMI) are shown as:
NA20
Notes are highlighted with cursive letters inside colored bar
Note: Useful description note
Glossary/definitions
I
En Relay residual nominal current
I
Enp Residual CT primary nominal current
I
nRelay phase nominal current
I
np Phase CT primary nominal current
I
BBasic current: it represents the nominal current of the line or trans-
former, referred to the nominal current of the CT’s for thermal image
protection
37 Undercurrent ANSI code
46 Negative sequence overcurrent ANSI code
49 Thermal image ANSI code
50/51 Phase overcurrent ANSI code
50N/51N Residual overcurrent ANSI code
BF Circuit breaker failure ANSI code
74CT CT supervision
74TCS Trip Circuit Supervision
DFR Digital Fault Recorder (Oscillography)
SER Sequential Event Recorder
SFR Sequential Fault Recorder
ANSI American National Standard Institute
IEEE Institute of Electrical and Electronics Engineers
IEC International Electrotechnical Commission
CENELEC Comité Européen de Normalisation Electrotechnique
52 o CB (Circuit Breaker) Circuit Breaker
52a Auxiliary contact in the breaker that is in the same position as the
breaker. It can be assigned to a binary input to locate the CB position
(Breaker failure and/or CB diagnostic functions). (52a open = CB open)
52b Auxiliary contact in the breaker that is in the opposite position as the
breaker (52b open = CB closed)
K1...K6...K10 Output relays
Pulse Output relay with pulse operation
tTR Output relay minimum pulse width
Latched Output relay with latched operation (manual reset) Output relay with
latched operation (automatic reset)
No-latched Output relay with no-latched operation (automatic reset)
CT Current Transformer
P1 IEC nomenclature for primary polarity mark of CTs (as an alternative to
a ANSI dot)
P2 IEC nomenclature for primary polarity mark of CTs (as an alternative to
Note 1 The graphic interface and the operation of the ThyVisor software are described in the relative chapters

INTRODUCTION 7
NA20 - Manual - 04 - 2022
a ANSI no-dot)
S1 IEC nomenclature for secondary polarity mark of CTs (as an alternative
to a ANSI dot)
S2 IEC nomenclature for secondary polarity mark of CTs (as an alternative
to a ANSI no-dot)
Self test Diagnostic
Start Leave an initial condition or reset condition (Pickup)
Trip Operation (with operate time)
Operating time Duration of time interval between the instant when the character-
istic quantity in reset condition is changed, under specified condi-
tions, and the instant when the relay operates
Dropout ratio The ratio of a reset value to an operate value in well-specified con-
ditions. The dropout ratio may be lower or greater than 1 according
as an over or under element is considered
Reset time Duration of the time interval between the instant when the charac-
teristic quantity in operate condition is changed, under specified
conditions, and the instant when the relay operates.
The stated reset time is related to a step variation of characteristic
quantity in operate condition to the reset condition.
Overshoot time The critical impulse time for a relay which is in its reset condition,
is the longest duration a specified change in the input energizing
quantity(ies) (characteristic quantity), which will cause the relay
to change to operate condition, can be applied without the relay
switches. The overshoot time is the difference from the operate time
and the critical impulse time.
The declared values for the overshoot time are applicable with the
lower setting value of the operation time.
MMI (Man Machine Interface) Operator front panel
ThyVisor Setting and monitoring software
Log file A text file that lists actions that have occurred (ThyVisor).
J2SE Java Platform Standard Edition
Subnet Mask (Ethernet nomenclature)
Sw Software
Fw Firmware
Upgrade Firmware upgrade
XML eXtensible Markup Language

INTRODUCTION 8
NA20 - Manual - 04 - 2022
Symbols.ai
Symbols
I>> Start
I>> BF_OUT
IPh Block2
Logic internal signal (output); may be a logical state (e.g.I>> Start ) or a numerical value
It is available for reading (ThySetter + communication interface)
Logic external signal (intput); may be a command coming from a binary input or a sw command
It is available for reading (ThySetter + communication interface)
Internal signal (e.g. Breaker Failure output state concerning to the 2nd threshold of the 50 element)
It is not available for reading (missing arrow)
AND and NAND logic gates
OR and NOR logic gates
Limit block (I>> threshold).
Computation block (Max phase current)
Threshold setting (e.g. pickup
I>>) .
The value is available for reading and is adjustable by means ThySetter + MMI.
Switch
ON delay timer with reset (tON delay)
ON delay timer without reset (tON delay)
OFF delay timer (dropout) without reset (tOFF delay)
Curve type (definite/inverse time)
0T
IL3
Max[IL1 ,IL2 ,IL3 ]
IL2
IL1
tON tON tON tON
t
RESET
INPUT
OUTPUT
tOFF
t
tOFF
INPUT
OUTPUT
tON tON tON
t
INPUT
OUTPUT
0T
tON
& &
≥1≥1
EXOR logic gate
tOFF
=1
I >>
II ≥
I>>
tON
RESET
0T
0 T

INTRODUCTION 9
NA20 - Manual - 04 - 2022
Symbols1 .ai
t
RESET
INPUT
OUTPUT
tOFF
tOFF
tOFF tOFF
Minimum pulse width operation for output relays (tTR )
tTR
t
tTR
INPUT
OUTPUT
tTR
0 T
tTR
t
tTR
INPUT
OUTPUT
Latched operating mode for output relays and LEDs
Pulse operating mode for output relays
t
INPUT
OUTPUT
Latched
tTR
T0
RESET
OFF delay timer (dropout) with reset (tOFF delay)

GENERAL 10
NA20 - Manual - 04 - 2022
2 GENERAL2 GENERAL
Preface
The relay type NA20 is typically used in HV, MV and LV radial networks as feeder or power trans-
former protection.
In solidly grounded systems the residual overcurrent protection can be used on feeders of any length,
while in ungrounded or Petersen coil and/or resistance grounded systems, the residual overcurrent
protection can be used on feeders of small length in order to avoid unwanted trippings due to the
capacitive current contribution of the feeder on external ground fault.
Beside to the phase and residual overcurrent protection, the following protective functions are pro-
vided:
• Thermal image protection of lines and power transformers.
• Undercurrent protection for monitoring of CB opening.
• Negative sequence protection against asymmetrical short circuits and unbalance loads.
• I2/I1protection against phase interruption under low-load condition.
Following input circuits are available:
• Three phase current and one residual current inputs with nominal currents independently select-
able at 1 A or 5 A using dip-switch.
• Two or five (optional) binary inputs.
• One block input (logic selectivity).
In addition to the main protection element, the breaker failure (BF), CT monitoring (74CT), Trip Circuit
Supervision (TCS) and programmable logic (PLC) are also provided.
Setting, programming and reading operations must be effected by means of Personal Computer with
ThyVisor software or by means of remote communication interface (RS485 bus and Ethernet network
or USB); all operations must be performed through MMI.
According to the hardware configurations, the NA20 protection relay can be shipped in various case
styles depending on the required mounting options:
• Flush.
• Projecting mounting.
• Rack.
• With separate operator panel.
Other options are:
• Auxiliary power supply operating range.
• Communication protocols.
Photo

GENERAL 11
NA20 - Manual - 04 - 2022
Main features
• Metallic case.
• Backlight LCD 4x16 Display.
• Eight LEDs that may be joined with matrix criteria to many and various functions.
• RESET key to clear LED indications and latched output relays.
• Two free settable binary inputs.
• Independently settable for start, trip, self-test and control six output relay (K1...K6) Each output
relay may be set with normally energized or normally de-energized operating mode and manual or
automatic reset (latched/no-latched).
• Rear Ethernet communication port, with MODBUS TCP/IP® protocol, with RJ45 (copper wires) or
FX (optical fiber) connection.
• Rear RS485 port, with ModBus protocol.
• USB front serial port (local communication for ThyVisor).
• Real time clock with super capacitor.
The most significant constructive features are:
• Galvanically insulated input and output circuits (communication and binary circuits included).
• Optimum filtering of input signals through combined use of analog and digital filters.
• Traditional electromechanical-type final output contacts with continuous monitoring of control coil
continuity.
• Auxiliary supply comprising a switching-type voltage stabilizing circuit having a very wide working
range and a very small power dissipation
• Nominal frequency: 50 or 60 Hz.
The most significant operating features are:
• Programming of operating modes and parameters by means of the front keys and alphanumeric
display, with a programming procedure based on carrying out guided selections and on explicit and
immediate signalling of the operations being performed, so that such procedure can be carried out
without coding tables or mnemonic informations.
• The feature modification operations do not interrupt the normal functions of the relay.
• Impossibility of programming unacceptable parameter values, thanks to the automatic limitation of
top and bottom scale values for the relative setting ranges.
• Currents are sampled 24 times per period and measured in the effective value (RMS) of the funda-
mental component using the DFT (Discrete Fourier Transform) algorithm and digital filters.
• The fault recorder (SFR) runs continuously capturing in circular mode the last twenty events upon
trigger of binary input/output and/or element pickup (start-trip).
• The event recorder (SER) runs continuously capturing in circular mode the last three hundred
events upon trigger of binary input/output.
• Digital fault recorder (DFR) in COMTRADE format (oscillography).

TECHNICAL DATA 12
NA20 - Manual - 04 - 2022
3 TECHNICAL DATA3 TECHNICAL DATA
3.1 GENERAL
Product standard for measuring relays
Reference standards IEC 60255-1 Part 1: Common requirements
Mechanical data
Mounting:
• Flush.
• Projecting.
• Rack.
• Separated operator panel.
External dimensions (Flush mounting) 177 x 107 x 235 (high x width x depth)
Terminals screw connection
Mass (Flush mounting) 2.0 kg
Reference standards EN 60529, EN 60529/A1
Degrees of protection provided by enclosures (IP Code)
• Front IP52
• Terminals IP20
Insulation
Reference standards EN 60255-5, IEC 60255-27
High voltage test (50 Hz - 60 s)
• Auxiliary power supply 2 kV
• Input circuits 2 kV
• Output circuits 2 kV
• Output circuits (between open contacts) 1 kV
• Comunication circuits 500 V
Impulse voltage withstand test (1.2/50 µs):
• Auxiliary power supply 5 kV (Common mode) - 2kV (Differential mode)
• Input circuits 5 kV
• Output circuits 5 kV
• Output circuits (between open contacts) 1 kV
Insulation resistance >100 MW
Voltage dip and interruption
Reference standards EN 61000-4-29, IEC 60255-22-11
Voltage dips, short interruptions and voltage variations on dc input power port immunity tests
• Interruption (UT=40%) 100 ms
• Interruption (UT=0%) 50 ms
• Voltage variations (UT=80...120%) 10 s
EMC tests for interference immunity
Reference standards IEC 60255-26, EN 60255-26
Product standard for measuring relays
Generic standards immunity for industrial environments EN 61000-6-2
• Electromagnetic compatibility requirements for measuring relays and protection equipment
Apparati di automazione e controllo per centrali e stazioni elettriche
• Compatibilità elettromagnetica - Immunità ENEL REMC 02
• Normativa di compatibilità elettromeccanica per apparati e sistemi
ENEL REMC 01
Reference standards EN 60255-22-1 IEC 60255-22-1
EN 61000-4-12 EN 61000-4-12
Damped oscillatory wave
• 0.1 MHz and 1 MHz common mode 2.5 kV
• 0.1 MHz and 1 MHz differential mode 1.0 kV
• Ring wave common mode 2.0 kV
• Ring wave differential mode 1.0 kV
Reference standards EN 60255-22-2 IEC 60255-22-2
EN 61000-4-2 IEC 61000-4-2
Electrostatic discharge
• Contact discharge 6 kV
• Air discharge 8 kV
Reference standards EN 60255-22-3 IEC 60255-22-3
EN 61000-4-3 IEC 61000-4-3
Radiated radio-frequency fields
• 80...1000 MHz AM 80% 10 V/m

TECHNICAL DATA 13
NA20 - Manual - 04 - 2022
• 900 MHz Pulse modulated 10 V/m
Reference standards EN 60255-22-4 IEC 60255-22-4
EN 61000-4-4 IEC 61000-4-4
Fast transient burst (5/50 ns)
• Auxiliary power supply 2 kV
• Input circuits 4 kV
Reference standards EN 60255-22-5 IEC 60255-22-5
EN 61000-4-5 IEC 61000-4-5
High energy pulse
• Uaux (line-to-ground 10 ohm, 9 mF) 2 kV
• Uaux (line-to-line 0 ohm, 18 mF) 1 kV
• I/O ports (line-to-ground 40 ohm, 0.5 mF) 2 kV
• I/O ports (line-to-line 40 ohm, 0.5 mF) 1 kV
Reference standards EN 60255-22-6 IEC 60255-22-6
EN 61000-4-6 IEC 61000-4-6
Conducted radio-frequency fields
• 0.15...80 MHz AM 80% 1kHz 10 V
Reference standards EN 60255-22-7 IEC 60255-22-7
EN 61000-4-16 IEC 61000-4-16
Power frequency immunity tests
• Dc voltage 30 V
• 50 Hz continuously 30 V
• 50 Hz 1 s 300 V
• 0.015...150 kHz 30 V
Reference standards EN 61000-4-8 IEC 61000-4-8
Magnetic field 50 Hz
• 50 Hz continuously 100 A/m
• 50 Hz 1 s 1 kA/m
Reference standards EN 61000-4-10 IEC 61000-4-10
Damped oscillatory magnetic field
• Damped oscillatory wave 0.1 MHz 30 A/m
• Damped oscillatory wave 1 MHz 30 A/m
Emission
Reference standards EN 60255-25 IEC 60255-25
EN 61000-6-4 IEC 61000-6-4
EN 55011 CISPR 11
Electromagnetic emission tests
• Conducted emission auxiliary power supply 0.15...0.5 MHz 79 dB mV
• Conducted emission auxiliary power supply 0.5...30 MHz 73 dB mV
• Radiated emission 30...230 MHz 40 dB mV/m
• Radiated emission 230...1000 MHz 47 dB mV/m
Mechanical tests
Reference standards EN 60255-21-1 EN 60255-21-2 RMEC01
Vibration, shock, bump and seismic tests on measuring relays and protection equipment
• EN 60255-21-1 Vibration tests (sinusoidal) Class 1
• EN 60255-21-2 Shock and bump test Class 1
Climatic tests
Reference standards IEC 60068-x ENEL R CLI 01 CEI 50
Environmental testing
Ambient temperature -25...+70 °C
Storage temperature -40...+85 °C
Relative humidity 10...95 %
Atmospheric pressure 70...110 kPa
Safety
Reference standards IEC 60255-27
Safety requirements for electrical equipment for measurement, control and laboratory use
Pollution degree 3
Reference voltage 250 V
Overvoltage category III
Certifications
Reference standards
Product standard for measuring relays EN 50263
CE Conformity
• EMC Directive 2014/30/EC
• Low Voltage Directive 2014/35/EC
Type tests IEC 60255-1

TECHNICAL DATA 14
NA20 - Manual - 04 - 2022
3.2 INPUT CIRCUITS
Auxiliary power supply Uaux
Voltage
Nominal value (range) 24...48 V~/-
115...230 V~/110...220 V-
Operative range (each one of the above nominal values) 19...60 V~/-
85...265 V~/75...300 V-
Inrush current (max)
• 24 V- 6 A, 5 ms
• 48 V- 14 A, 5 ms
• 110 V- 20 A, 1 ms
• 230 V~ 50 A, 1 ms
Frequency (for alternate voltage supply) 45...66 Hz
Max distortion factor ( for alternating voltage supply) 15%
Max alternating component (for dc voltage supply):
• Full wave rectified sine wave 100 %
• Sine wave 80 %
Power consumption:
• Maximum (energized relays, Ethernet TX) 10 W (20 VA)
• Maximum (energized relays, Ethernet FX) 15 W (25 VA)
Phase current input circuits
Relay nominal phase current In1 A or 5 A selectable by dip-switch
Permanent overload 25 A
Thermal overload (1 s) 500 A
Dynamic overload (half cycle) 1250 A
Rated consumption (for any phase) ≤0.002 VA with In=1 A
≤0.04 VA with In=5 A
Residual current input circuit
Relay nominal residual current IEn 1 A or 5 A selectable by dip-switch
Permanent overload 25 A
Thermal overload (1 s) 500 A
Dynamic overload (half cycle) 1250 A
Rated consumption ≤0.006 VA with IEn=1 A
≤0.12 VA with IEn=5 A
Binary input circuits
Quantity 2 or 5 (optional)
Type optocoupler
Operative range 24...265 V~/-
Min activation voltage 18 V
Max consumption, energized 3 mA
Block input (Logic selectivity)
Quantity 1
Type polarized wet input (powered by internal isolated supply)
Max consumption, energized 5 mA
3.3 OUTPUT CIRCUITS
Relays
Quantity 6
Type of contacts K1, K2 changeover (SPDT, type C)
Type of contacts K3, K4, K5 make (SPST-NO, type A)
Type of contacts K6 break (SPST-NC, type B)
Nominal current 8 A
Nominal voltage/max switching voltage 250 V~/400 V~
Breaking capacity:
• Direct current (L/R = 40 ms) 50 W
• Alternating current (l= 0,4) 1250 VA
Make 1000 W/VA
Short duration current (0,5 s) 30 A
Minimum switching load 300 mW (5 V/ 5 mA)
Life:
• Mechanical 106operations
• Electrical 105operations
Block output (Logic selectivity)
Quantity 1
Type optocoupler

TECHNICAL DATA 15
NA20 - Manual - 04 - 2022
3.4 MMI
Display 16 x 4 alphanumeric LCD
LEDs
Quantity 8
• ON/fail (green) 1
• Start (yellow) 1
• Trip (red) 1
• Freely allocatable (red) 5
Keyboard 8 keys
3.5 COMMUNICATION INTERFACES
Local port
Connection USB Type B
Protocol Modbus RTU®
Remote ports
RS485
• Connection screw terminals
• Baud rate 1200...57600 bps
• Protocol[1] ModBus®RTU
IEC 60870-5-103
DNP3[2]
Ethernet 100BaseT
• Connection[3] Optical fiber 1300 nm, ST
100 Base TX, RJ45
• Baud rate 100 Mbps
• Protocol ModBus®TCP/IP
Note 1 Different version must be selected at ordering
Note 2 Extended list of reading variables (eg. )
Note 3 Different version must be selected at ordering

TECHNICAL DATA 16
NA20 - Manual - 04 - 2022
3.6 GENERAL SETTINGS
Relay nominal frequency (fn) 50, 60 Hz
Relay phase nominal current (In) 1 A or 5 A [1]
Phase CT primary nominal current (Inp) 1 A...10 kA
1...499 A (step 1 A)
500...4990 A (step 10 A)
5000...10000 A (step 100 A)
Relay residual nominal current (IEn) 1 A or 5 A [1]
Residual CT primary nominal current (IEnp) 1 A...10 kA
1...499 A (step 1 A)
500...4990 A (step 10 A)
5000...10000 A (step 100 A)
3.7 PROTECTIVE FUNCTIONS
Base current - IB[2]
Base current (IB) 0.10...2.50 In (step 0.01 In)
Thermal protection with Pt100 probes - 26[3]
ThAL1...8 Alarm:
Alarm threshold 26 PT1...PT8 (ThAL1...8) 0...200 °C
Operating time ThAL1...8 (tThAL1...8) 0....100 s
Th>1...8 Trip:
Trip threshold 26 PT1...PT8 (Th>1...8) 0...200 °C
Operating time ThAL1...8 (tTh>1...8)0....100 s
Undercurrent - 37
37 Operating logic (Logic37) AND/OR
Definite time
37 First threshold definite time (I<def) 0.10...1.00 In(step 0.01 In)
I<def Operating time (t<def) 0.04...200 s
0.04...9.99 s (step 0.01 s)
10.0...99.9 s (step 0.1 s)
100...200 s (step 1 s)
Pickup time ≤ 0.03 s
Dropout ratio 1.03...1.05
Dropout time ≤ 0.05 s
Overshoot time 0.03 s
Pickup accuracy ± 0.5% with 0.1 In,±0.2% with 1 In
Operate time accuracy 5% or ± 10 ms
Negative sequence overcurrent - 46
I2> Element
I2> Curve type (I2>Curve)DEFINITE
IEC/BS A, B, C
ANSI/IEEE MI, VI, EI
I2t, EM
I2CLP> Activation time (t2CLP>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
I2> Reset time delay (t2>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
46 First threshold definite time (I2>def) 0.100...10.00 In
0.100...0.999 In (step 0.001 In)
1.00...10.00 In (step 0.01 In)
I2>def within CLP (I2CLP>def) 0.100...10.00 In
0.100...0.999 In (step 0.001 In)
1.00...10.00 In (step 0.01 In)
I2>def Operating time (t2>def) 0.03...200 s
0.03...9.99 s (step 0.01 s)
10.0...99.9 s (step 0.1 s)
100...200 s (step 1 s)
Note 1 The nominal current settings doesn’t concern the protection elements; they must agree with hardware setting (dip-switch 1 A or 5 A) .
Note 2 The basic current IBrepresents the nominal current of the line or transformer, referred to the nominal current of the CT’s for thermal image
protection. If the secondary rated current of the line CT’s equals the rated current of the NA20 relay, as usually happens, the IBvalue is the ratio
between the rated current of the protected element and the primary rated current of the CT’s
Note 3 The 26 element is available when the MPT module is connect on Thybus and enabled

TECHNICAL DATA 17
NA20 - Manual - 04 - 2022
Inverse time [1]
46 First threshold inverse time (I2>inv) 0.100...10.00 In
0.100...0.999 In (step 0.001 In)
1.00...5.00 In (step 0.01 In)
I2>inv within CLP (I2CLP>inv) 0.100...10.00 In
0.100...0.999 In (step 0.001 In)
1.00...10.00 In (step 0.01 In)
I2>inv Operating time (t2>inv) 0.02...60.0 s
0.02...9.99 s (step 0.01 s)
10.0...60.0 s (step 0.1 s)
I2>> Element
I2CLP>> Activation time (t2CLP>>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
I2>> Reset time delay (t2>>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
46 Second threshold definite time (I2>>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...40.00 In (step 0.01 In)
I2>>def within CLP (I2CLP>>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...40.00 In (step 0.01 In)
I2>>def Operating time (t2>>def) 0.03...10.00 s (step 0.01 s)
Pickup time ≤ 0.03 s
Dropout ratio 0.95...0.98
Dropout time ≤ 0.05 s
Overshoot time 0.03 s
Pickup accuracy 1% with I2 ≥ 0.5 In
Operate time accuracy 5% or ± 10 ms
Negative sequence / positive sequence current ratio - I2 / I1
I21> Element
I21CLP> Activation time (t21CLP>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
I2 /I1> First threshold definite time (I21>def) 0.10...1.00 In(step 0.01 In)
I2 /I1> within CLP ((I21CLP>def 0.10...1.00 In(step 0.01 In)
I21>def Operating time (t21>def) 0.04...15000 s
0.04...9.99 s (step 0.01 s)
1...15000 s (step 1 s)
Pickup time ≤ 0.03 s
Dropout ratio 0.95...0.98
Dropout time ≤ 0.05 s
Overshoot time 0.03 s
Pickup accuracy 1% with I1and I2 ≥ 0.5 In
Operate time accuracy 5% or ± 10 ms
Note 1 Standard Inverse Time (IEC 255-3/BS142 type A or SIT): t = 0.14 · t2>inv / [(I2/I2>inv)0.02 - 1]
Very Inverse Time (IEC 255-3/BS142 type B or VIT): t = 13.5 · t2>inv / [(I2/I2>inv) - 1]
Extremely Inverse Time (IEC 255-3/BS142 type C or EIT): t = 80 · t2>inv / [(I2/I2>inv)2 - 1]
Moderately Inverse (ANSI/IEEE type MI): t = t2>inv · {0.01 / [(I2/I2>inv)0.02 - 1] + 0.023}
Very Inverse (ANSI/IEEE type VI): t = t2>inv · {3.922 / [(I2/I2>inv)2- 1] + 0.098}
Extremely Inverse (ANSI/IEEE type EI): t = t2>inv · {5.64 / [(I2/I2>inv)2- 1] + 0.024}
I-squared-t (I 2t = K): t = 16 · t2>inv / (I2/I2>inv)2
Electromechanical (EM): t = 0.28 · t2>inv / [-0.236 · (I2/I2>inv)-1+ 0.339]
t:operate time
I2>inv:pickup value
t2>inv:operate time setting
Asymptotic reference value: 1.1 I2>nv
Minimum operate time: 0.1 s
Equation is valid for 1.1 ≤ I2/I2>inv ≤ 20
With I2>inv pickup ≥ 2.5 In, the upper limit is 50 In

TECHNICAL DATA 18
NA20 - Manual - 04 - 2022
Thermal image - 49
Common configuration:
Initial thermal image
D qIN (DthIN) 0.0...1.0 D qB(step 0.1 D qB)[1]
Reduction factor at inrush (KINR) 1.0...3.0 (step 0.1)
Thermal time constant t (T) 1...200 min (step 1 min)
DthIN activation time (tdthCLP) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
DthAL1 Element
49 First alarm threshold (DthAL1)0.3...1.0
D qB(step 0.1 D qB)
DthAL2 Element
49 Second alarm threshold (DthAL2)0.5...1.2
D qB(step 0.1 D qB)
Dth> Element
49 Trip threshold (Dth>) 1.100...1.300
D qB (step 0.001 D qB)
Pickup accuracy ± 1% with 0.1 In,±1% with 1 In
Operate time accuracy 5% or ± 10 ms
Phase overcurrent - 50/51
I> Element
I> Curve type (I>Curve)DEFINITE
IEC/BS A, B, C, B-LI
ANSI/IEEE MI, VI, EI
RECTIFIER, I2t or EM
ICLP> Activation time (tCLP>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
I> Reset time delay (t>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
50/51 First threshold definite time (I>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...9.99 In (step 0.01 In)
10.0...40.0 In (step 0.1 In)
I>def within CLP (ICLP>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...9.99 In (step 0.01 In)
10.0...40.0 In (step 0.1 In)
I>def Operating time (t>def) 0.04...200.00 s
0.04...9.99 s (step 0.01 s)
10.0...99.9 s (step 0.1 s)
100...200 s (step 1 s)
Inverse time[2]
50/51 First threshold inverse time (I>inv) 0.100...20.00 In
0.100...0.999 In (step 0.001 In)
1.00...20.00 In (step 0.01 In)
I>inv within CLP (ICLP>inv) 0.100...20.00 In
0.100...0.999 In (step 0.001 In)
1.00...20.00 In (step 0.01 In)
I>inv Operating time (t>inv) 0.02...60.0 s
0.02...9.99 s (step 0.01 s)
10.0...60.0 s (step 0.1 s)
Note 1 D q is the thermal image (p.u. of the basic over temperature corresponding to the basic current IB).
Assuming that the secondary rated current of the line CT’s equals the rated current of the NA20 relay, as usually happens, the IBvalue is the
ratio between the rated current of the protected element and the primary rated current of the CTs
Note 1 Standard Inverse Time (IEC 255-3/BS142 type A or SIT): t = 0.14 · t>inv / [(I/I>inv)0.02 - 1]
Very Inverse Time (IEC 255-3/BS142 type B or VIT): t = 13.5 · t>inv / [(I/I>inv) - 1]
Extremely Inverse Time (IEC 255-3/BS142 type C or EIT): t = 80 · t>inv / [(I/I>inv)2 - 1]
Long time Inverse Time (IEC 255-3/BS B LI): t = 120 · t>inv / [(I/I>inv)- 1]
Moderately Inverse (ANSI/IEEE type MI): t = t>inv · {0.01 / [(I/I>inv)0.02 - 1] + 0.023}
Very Inverse (ANSI/IEEE type VI): t = t>inv · {3.922 / [(I/I>inv)2- 1] + 0.098}
Extremely Inverse (ANSI/IEEE type EI): t = t>inv · {5.64 / [(I/I>inv)2- 1] + 0.024}
I-squared-t (I 2t = K): t = 16 · t>inv / (I/I>inv)2
Electromechanical (EM): t = 0.28 · t>inv / [-0.236 · (I/I>inv)-1+ 0.339]
RECTIFIER (RI): t = 2351 · t>inv / [(I/I>inv)5.6- 1]
t:operate time
I>inv:pickup value
t>inv:operate time setting
Asymptotic reference value: 1.1 I>nv
Minimum operate time: 0.1 s
Equation is valid for 1.1 ≤ I/I>inv ≤ 20
With I>inv pickup ≥ 2.5 In, the upper limit is 50 In

TECHNICAL DATA 19
NA20 - Manual - 04 - 2022
I>> Element
I>> Curve type (I>>Curve)DEFINITE or I2t
ICLP>> Activation time (tCLP>>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
I>> Reset time delay (t>>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
50/51 Second threshold definite time (I>>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...9.99 In (step 0.01 In)
10.0...40.0 In (step 0.1 In)
I>>def within CLP (ICLP>>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...9.99 In (step 0.01 In)
10.0...40.0 In (step 0.1 In)
I>>def Operating time (t>>def) 0.03...10.00 s (step 0.01 s)
Inverse time
50/51 Second threshold inverse time (I>>inv) 0.100...20.00 In
0.100...0.999 In (step 0.001 In)
1.00...20.00 In (step 0.01 In)
I>>inv within CLP (ICLP>>inv) 0.100...20.00 In
0.100...0.999 In (step 0.001 In)
1.00...20.00 In (step 0.01 In)
I>>inv Operating time (t>>inv) 0.02...10.00 s (step 0.01 s)
I>>> Element
ICLP>>> Activation time (tCLP>>>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
I>>> Reset time delay (t>>>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
50/51 Third threshold definite time (I>>>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...9.99 In (step 0.01 In)
10.0...40.0 In (step 0.1 In)
I>>>def within CLP (ICLP>>>def) 0.100...40.0 In
0.100...0.999 In (step 0.001 In)
1.00...9.99 In (step 0.01 In)
10.0...40.0 In (step 0.1 In)
I>>>def Operating time (t>>>def) 0.03...10.00 s (step 0.01 s)
Pickup time ≤ 0.03 s
Dropout ratio 0.95...0.98
Dropout time ≤ 0.05 s
Overshoot time 0.03 s
Pickup accuracy ± 0.5% with 0.1 In,±0.2% with 1 In
Operate time accuracy 5% or ± 10 ms
Residual overcurrent - 50N/51N
IE> Element
IE> Curve type (IE>Curve)DEFINITE
IEC/BS A, B, C, B-LI
ANSI/IEEE MI, VI, EI
EM
IECLP> Activation time (tECLP>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
IE> Reset time delay (tE>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
50N/51N First threshold definite time (IE>def) 0.002...10.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...10.00 IEn (step 0.01 IEn)
IE>def within CLP (IECLP>def) 0.002...10.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...10.00 In (step 0.01 IEn)
IE>def Operating time (tE>def) 0.04...200 s
0.04...9.99 s (step 0.01 s)
10.0...99.9 s (step 0.1 s)
100...200 s (step 1 s)

TECHNICAL DATA 20
NA20 - Manual - 04 - 2022
Inverse time[1]
50N/51N First threshold inverse time (IE>inv) 0.002...2.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...2.00 IEn (step 0.01 IEn)
IE>inv within CLP (IECLP>inv) 0.002...2.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...2.00 IEn (step 0.01 IEn)
IE>inv Operating time (tE>inv) 0.02...60.0 s
0.02...9.99 s (step 0.01 s)
10.0...60.0 s (step 0.1 s)
IE>> Element
IECLP>> Activation time (tECLP>>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
IE>> Reset time delay (tE>>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
50N/51N Second threshold definite time (IE>>def) 0.002...10.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...10.00 IEn (step 0.01 IEn)
IE>>def within CLP (IECLP>>def) 0.002...10.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...10.00 IEn (step 0.01 IEn)
IE>>def Operating time (tE>>def) 0.03...10.00 s (step 0.01 s)
IE>>> Element
IECLP>>> Activation time (tECLP>>>) 0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
IE>>> Reset time delay (tE>>>RES)0.00...100.0 s
0.00...9.99 s (step 0.01 s)
10.0...100.0 s (step 0.1 s)
Definite time
50N/51N Third threshold definite time (IE>>>def) 0.002...10.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...10.00 IEn (step 0.01 IEn)
IE>>>def within CLP (IECLP>>>def) 0.002...10.00 IEn
0.002...0.999 IEn (step 0.001 IEn)
1.00...10.00 IEn (step 0.01 IEn)
IE>>>def Operating time (tE>>>def) 0.03...10.00 s (step 0.01 s)
Pickup time ≤ 0.03 s
Dropout ratio 0.95...0.98
Dropout time ≤ 0.05 s
Overshoot time 0.03 s
Pickup accuracy ± 0.5% with 0.01 IEn,±0.2% with 1 IEn
Operate time accuracy 5% or ± 10 ms
Breaker failure - BF
BF Phase current threshold (IBF>) 0.05...1.00 In (step 0.01 In)
BF Residual current threshold (IEBF>) 0.01...2.00 IEn (step 0.01 IEn)
BF Time delay(tBF) 0.06...10.00 s (step 0.01 s)
Dropout ratio 0.95...0.98
Dropout time ≤ 0.05 s
IBF>Pickup accuracy ± 0.5% with 0.1 InL
± 0.2% with 1 InL
IEBF>Pickup accuracy ± 0.5% with 0.01 IEn
± 0.2% with 1 IEn
Operate time accuracy 5% or ± 10 ms
Note 1
Standard Inverse Time (IEC 255-3/BS142 type A or SIT): t = 0.14 · tE>inv / [(IE/ IE>inv)0.02 - 1]
Very Inverse Time (IEC 255-3/BS142 type B or VIT): t = 13.5 · tE>inv / [(IE/IE>inv) - 1]
Extremely Inverse Time (IEC 255-3/BS142 type C or EIT): t = 80 · tE>inv / [(IE/IE>inv)2 - 1]
Long time Inverse Time (IEC 255-3/BS B LI): t = 120 · tE>inv / [(IE/IE>inv) - 1]
Moderately Inverse (ANSI/IEEE type MI): t = tE>inv · {0.01 / [(IE/IE>inv)0.02 - 1] + 0.023}
Very Inverse (ANSI/IEEE type VI): t = tE>inv · {3.922 / [(IE/IE>inv)2- 1] + 0.098}
Extremely Inverse (ANSI/IEEE type EI): t = tE>inv · {5.64 / [(IE/IE>inv)2- 1] + 0.024}
Electromechanical (EM): t = 0.28 · tE>inv / [-0.236 · (IE/IE>inv)-1+ 0.339]
IE:residual current input
t:operate time
IE>inv:pickup value; tE>inv:operate time setting
Asymptotic reference value: 1.1 IE>
Minimum operate time: 0.1 s
Equation is valid for 1.1 ≤ IE/ IE>inv ≤ 20, with IE>inv pickup ≥ 0.5 IEn, the upper limit is 10 IEn