High-Speed Algorithm for Detecting the Moment of Mode Change in Protection Based on the Differential Principle

Today, due to a series of incorrect operations of high-speed protection during external short circuits with current transformers (CT) saturation at large electric power facilities, the work direction of the industry regulator, represented by the system operator and the Ministry of Energy (hereinafter referred to as the regulator), is related to the regulation of CTs and the preparation of requirements for the operation of relay protection and automation systems in transient modes [1 , 2] . Relay protection and automation developers are required to indicate the minimum time before CT saturation, which ensures the correct operation of high-speed relay protection and automation, in the documentation [3] .