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 . 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 . AITAF provides end‑to‑end optical communication solutions, structured cabling, ODN, optical modules, fiber testing instruments, data center networks, base station energy, smart city communications. Protective relays and devices have been developed over 100 years ago to provide “lastline”of. This happens because the main function of protection devices is related to operation under fault conditions so these devices cannot be tested under normal operating conditions. This problem is worsened by the growing complexity of protection arrangements, application of protection relays with. The first relays were Electromechanical (EM): machines with moving parts actuated by coils connected to current and voltage sources. These required regular testing, adjustments and maintenance to ensure continued functioning.