MT 2 - TC 95/MT 2

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 60255-26:2013 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 60255-22-5:2008 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.