TC 95 - Measuring relays and protection equipment

IEC 60255-27:2023 specifies the product safety requirements for measuring relays and protection equipment having a rated AC voltage up to 1 000 V, or a rated DC voltage up to 1 500 V. This document specifies essential safety requirements to minimize the risk of fire and hazards caused by electric shock or injury to the user and property. This document specifies only product safety requirements; functional performance of the equipment is not covered. This document covers all the ways in which the equipment can be mounted and used in cabinets, racks and panels. This document also applies to auxiliary devices such as shunts, series resistors, transformers, auxiliary control panels, display devices, etc., that are used in conjunction with measuring relays and protection equipment and are tested together.

IEC 60255-26:2023 specifies the requirements for electromagnetic compatibility for measuring relays and protection equipment. It is applicable to measuring relays and protection equipment and combinations of devices to form schemes for power system protection including the control, monitoring, communication and process interface equipment used with those systems. This document specifies limits and test methods, for measuring relays and protection equipment in relation to electromagnetic emissions which might cause interference in other equipment. This document specifies the immunity test requirements for measuring relays and protection equipment in relation to continuous and transient, conducted and radiated disturbances, including electrostatic discharges.

IEC 60255-1:2022 specifies common rules and requirements applicable to measuring relays and protection equipment, including any combination of equipment to form a distributed protection scheme for power system protection such as control, monitoring and process interface equipment, to obtain uniformity of requirements and tests. This document covers the main technologies in use today; other emerging technologies present specific EMC and safety issues but the philosophy in this document will be applied.
This second edition cancels and replaces the first edition published in 2009. This edition includes the following significant technical changes with respect to the previous edition:
a. scope of document clarified;
b. merging units and communications as an integral part of the protection added;
c. binary output clarification expanded;
d. environmental operating conditions added (Annex B);
e. test reference conditions added;
f. multiple changes to improve understanding across most clauses;
g. derating by manufacturer added;
h. safety and EMC tests removed from document and referenced only;
i. relay setting and type test guidelines modified (Annex A)
j. battery monitor port and low power instrument transformers added.

IEC 60255-187-1:2021 specifies the minimum requirements for functional and performance evaluation of (longitudinal) differential protection designed for the detection of faults in ac motors, generators and transformers. This document also defines how to document and publish performance test results. This document defines the influencing factors that affect the accuracy under steady state conditions and performance characteristics during dynamic conditions. The test methodologies for verifying performance characteristics and accuracy are also included in this document.
This document, together with IEC 60255-187-2 and IEC 60255-187-3, cancels and replaces IEC 60255-13. This document includes the following significant technical changes with respect to IEC 60255-13:
a) IEC 60255-13 has been significantly revised to follow the common structure of the functional standards for protection relays (IEC 60255-1xx series). IEC 60255-187-1 has been developed to address the restrained and unrestrained differential protection of motors, generators and transformers. The revisions include detailed description of the functions including the performance specification, testing and documentation requirements.
The contents of the corrigendum of April 2023 have been included in this copy.

IEC 60050-447:2020 gives the general terminology used in measuring relays and protection equipment, as well as general terms pertaining to specific applications and associated technologies. This new edition reviews and complements the previous one. It has the status of a horizontal standard in accordance with IEC Guide 108:2006. This terminology is consistent with the terminology developed in the other specialized parts of the IEV.

IEC 60255-181:2019 specifies the minimum requirements for functional and performance evaluation of frequency protection. This document also defines how to document and publish performance test results.
This document covers the functions based on frequency measurement or rate of change of frequency measurements. This document also covers frequency protection where additional blocking elements are used.
This document defines the influencing factors that affect the accuracy under steady state conditions and performance characteristics during dynamic conditions. The test methodologies for verifying performance characteristics and accuracy are also included in this document.

IEC/IEEE 60255-118-1:2018 is used for synchronized phasor measurement systems in power systems. It defines a synchronized phasor (synchrophasor), frequency, and rate of change of frequency measurements. It describes time tag and synchronization requirements for measurement of all three of these quantities. It specifies methods for evaluating these measurements and requirements for compliance with the standard under both static and dynamic conditions. It defines a phasor measurement unit (PMU), which can be a stand-alone physical unit or a functional unit within another physical unit. This document does not specify hardware, software or a method for computing phasors, frequency, or rate of change of frequency.

IEC 60255-121:2014 specifies minimum requirements for functional and performance evaluation of distance protection function typically used in, but not limited to, line applications for effectively earthed, three-phase power systems. This standard also defines how to document and publish performance tests. This standard covers distance protection function whose operating characteristic can be defined on an impedance plane and includes specification of the protection function, measurement characteristics, phase selection, directionality, starting and time delay characteristics. The test methodologies for verifying performance characteristics and accuracy are included in this standard. The standard defines the influencing factors that affect the accuracy under steady state conditions and performance characteristics during dynamic conditions. It also includes the instrument transformer requirements for the protection function. The general requirements for measuring relays and protection equipment are defined in IEC 60255-1.

IEC 60255-27:2013 describes the product safety requirements for measuring relays and protection equipment having a rated a.c. voltage up to 1 000 V with a rated frequency up to 65 Hz, or a rated d.c. voltage up to 1 500 V. Above these limits, IEC 60664-1 is applicable for the determination of clearance, creepage distance and withstand test voltage. This standard details essential safety requirements to minimize the risk of fire and hazards caused by electric shock or injury to the user. This new edition includes the following significant technical changes with respect to the previous edition:
- the removal of tables and diagrams which are from other standards and referring instead directly to the source standard;
- all aspects of IEC 60255-5 have been covered and this standard will be withdrawn.

IEC 60255-149:2013 specifies minimum requirements for thermal protection relays. This standard includes specification of the protection function, measurement characteristics and test methodologies. The object is to establish a common and reproducible reference for evaluating dependent time relays which protect equipment from thermal damage by measuring a.c. current flowing through the equipment. Complementary input energizing quantities such as ambient, coolant, top oil and winding temperature may be applicable for the thermal protection specification set forth in this standard. This standard covers protection relays based on a thermal model with memory function.

IEC 60255-26:2013 is applicable to measuring relays and protection equipment, taking into account combinations of devices to form schemes for power system protection including the control, monitoring, communication and process interface equipment used with those systems. This standard specifies the requirements for electromagnetic compatibility for measuring relays and protection equipment. The requirements specified in this standard are applicable to measuring relays and protection equipment in a new condition and all tests specified are type tests only. This new edition includes the following significant technical changes with respect to the previous edition:
- definition of test specifications, test procedures and acceptance criteria per phenomena and port under test in one document;
- extension of radiated emission measurement for frequencies above 1 GHz;
- limitation of radiated emission measurement at 3 m distance for small equipment only;
- addition of zone A and zone B test level on surge test;
- extension of tests on the auxiliary power supply port by a.c. and d.c. voltage dips, a.c. component in d.c. (ripple) and gradual shut-down/start-up;
- harmonization of acceptance criteria for immunity tests.

IEC 60255-24:2013 defines a format for files containing transient waveform and event data collected from power systems or power system models. The format is intended to provide an easily interpretable form for use in exchanging data. The standard is for files stored on currently used physical media such as portable external hard drives, USB drives, flash drives, CD, and DVD. This standard defines a common format for the data files and exchange medium needed for the interchange of various types of fault, test, and simulation data. The main changes with respect to the previous edition are as follows:
- this new edition allows single file format (with extension .CFF) in lieu of four separate files;
- the single file with .CFF extension contains four sections of information corresponding to .CFG, .INF, .HDR, and .DAT. The DAT section is either in ASCII or Binary;
- the following additional data file types are also supported: binary32 and float32.

IEC 60255-127:2010 specifies minimum requirements for over/under voltage relays. The standard includes specification of the protection function, measurement characteristics and time delay characteristics.

IEC 60255-151:2009 specifies minimum requirements for over/under current relays. It includes a specification of the protection function, measurement characteristics and time delay characteristics. Defines the influencing factors that affect the accuracy under steady state conditions and performance characteristics during dynamic conditions.

IEC 60255-1:2009 specifies common rules and requirements applicable to measuring relays and protection equipment including any combination of devices to form schemes for power system protection such as control, monitoring and process interface equipment in order to obtain uniformity of requirements and tests. Covers all measuring relays and protection equipment used for protection within the power system environment.

IEC 60255-26:2008 is applicable to measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems; it specifies the essential requirements for electromagnetic compatibility for measuring relays and protection equipment intended to be used at industrial locations. The main difference of this new edition with respect to the previous one concerns the references to IEC 61000-4 and to CISPR 22.

Describes the product safety requirements for measuring relays and protection equipment having a rated a.c. voltage up to 1 000 V with a rated frequency up to 65 Hz, or a rated d.c. voltage up to 1 500 V. Details essential safety requirements to minimize the risk of fire and hazards caused by electric shock or injury to the user. The contents of the corrigendum of March 2007 have been included in this copy.

Specifies the general requirements for 1 MHz burst immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. Is to be used in conjunction with IEC 61000-4-12.

Specifies the requirements for electromagnetic compatibility for measuring relays and protection equipment. Is applicable to measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems.

Specifies the general requirements for electrical fast transient immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with these systems. Is based on IEC 61000-4-4.

Specifies the general requirements for surge tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with these systems. Is based on IEC 61000-4-5.

Defines a format for files containing transient waveform and event data collected from power systems or power system models. Applies to files stored on physical media such as digital hard drives and diskettes.

Specifies the general requirements for radiated electromagnetic field disturbance tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. Is based on IEC 61000-4-3.

Specifies general requirements for electrostatic discharge tests of static measuring relays and protection equipment. Is based on IEC 1000-4-2 and refers to that standard where applicable.

Specifies the general requirements for radiated electromagnetic field immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. The tests are intended to confirm that the equipment under test will operate correctly when energised and subjected to an electromagnetic field. The main change with respect to the previous edition concerns the extension of the frequency range.

IEC 60255-22-4:2008 specifies the general requirements for electrical fast transient immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with these systems. Is based on IEC 61000-4-4. The objective of the tests is to confirm that the equipment under test will operate correctly when energized and subjected to repetitive fast transients (bursts) such as those originating from interrupting of inductive loads, relay contact bounce, etc. The main change with respect to the previous edition is the improvement of the test severity level regarding the repetition rate.

This edition supersedes the first edition of IEC 60255-8 (1978) and IEC 60255-17 (1982). Applies to dependent specified time electrical measuring relays which protect equipment from electrical thermal damage by the measurement of current flowing in protected equipment. States the particular requirements for thermal electrical relays. Is to be read in conjunction with higher level documents in the IEC 60255 series.

Is applicable to measuring relays and protection equipment in a new condition and all tests specified are type tests only. Lays down test severity levels, test equipment, test set-up, test procedure, criteria for acceptance, etc. This new edition is based on IEC 61000-4-18 and includes changes in the test equipment and test procedures.

IEC 60255-22-2:2008 specifies the general requirements for electrostatic discharge tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. Is based on IEC 61000-4-2. The object of the tests is to confirm that the equipment being tested will not mal-operate when energized and subjected to an electrostatic discharge. The main changes with respect to the previous edition are the improvement of the test severity level, test set-up and test report.

Lays down general requirements for the insulation coordination of measuring relays and protection equipment. Gives guidance for the selection of clearances and creepage distances and other aspects related to the insulation of measuring relays and protection equipment; specifies requirements for voltage tests and insulation resistance measurement.

IEC 60255-22-5:2008 specifies the general requirements for surge immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. Is based on IEC 61000-4-5. The objective of the tests is to confirm that the equipment under test will operate correctly when energized and subjected to high-energy disturbances on the power and interconnection lines, caused by surge voltages from switching and lightning effects. The main change in this new edition concerns line to earth tests.

IEC 60255-11:2008 specifies the general requirements for a.c. and d.c. power supplies, for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. The objective of the tests is to confirm that the equipment under test will operate correctly when energised and subjected to dips, interruptions and alternating components (ripple). The main differences with respect to the previous edition are as follows: addition of voltage dips and interruptions test in a.c.; addition of gradual shut-down/start-up test; addition of reversal of d.c. power supply polarity test.

IEC 60255-22-4:2008 specifies the general requirements for electrical fast transient immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with these systems. Is based on IEC 61000-4-4. The objective of the tests is to confirm that the equipment under test will operate correctly when energized and subjected to repetitive fast transients (bursts) such as those originating from interrupting of inductive loads, relay contact bounce, etc. The main change with respect to the previous edition is the improvement of the test severity level regarding the repetition rate.

IEC 60255-22-2:2008 specifies the general requirements for electrostatic discharge tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. Is based on IEC 61000-4-2. The object of the tests is to confirm that the equipment being tested will not mal-operate when energized and subjected to an electrostatic discharge. The main changes with respect to the previous edition are the improvement of the test severity level, test set-up and test report.

Is applicable to measuring relays and protection equipment in a new condition and all tests specified are type tests only. Lays down test severity levels, test equipment, test set-up, test procedure, criteria for acceptance, etc. This new edition is based on IEC 61000-4-18 and includes changes in the test equipment and test procedures.

Specifies the general requirements for radiated electromagnetic field immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. The tests are intended to confirm that the equipment under test will operate correctly when energised and subjected to an electromagnetic field. The main change with respect to the previous edition concerns the extension of the frequency range.

Specifies general requirements for power frequency immunity tests for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems. The objective of the tests is to confirm that the equipment under test will operate correctly when energised and subjected to short duration, conducted, common and differential mode power frequency disturbances. Is based on IEC 61000-4-16.

Specifies the general requirements for conducted disturbances induced by electromagnetic fields for measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with those systems.

Lays down general requirements for the insulation coordination of measuring relays and protection equipment. Gives guidance for the selection of clearances and creepage distances and other aspects related to the insulation of measuring relays and protection equipment; specifies requirements for voltage tests and insulation resistance measurement.

Specifies the general requirements for the measurement of radio-frequency emissions emanating from measuring relays and protection equipment for power system protection, including the control, monitoring and process interface equipment used with such systems. Is based on CISPR 22.

Definitions. Standard values relating to energizing quantities influencing quantities. Fundamental characteristics relating to temperature rises and behaviour in service. Accuracy requirements relating to the characteristic quantity and specified times. Mechanical and electrical requirements. Markings and data. Methods of measurement. The contents of the corrigendum of September 1992 have been included in this copy.