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.

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    170 pages
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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.

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    188 pages
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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.

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    74 pages
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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.

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    302 pages
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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.

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    197 pages
    English and French language
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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.

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    93 pages
    English and French language
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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.

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    92 pages
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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.

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    144 pages
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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.

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    49 pages
    English and French language
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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.

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    63 pages
    English and French language
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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.

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    89 pages
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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.

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    17 pages
    English language
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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.

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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.

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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.

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    17 pages
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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.

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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.

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    19 pages
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