IEC 60255-1:2009

This standard specifies the general performance requirements of all electrical measuring relays and protection equipment used in the electrotechnical fields covered by the IEC. Supersedes IEC 60255-6 (1978) and its first supplement 60255-6 A (1980).

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.