Research on transient protection based on time-frequency domain features

With the high proportion of new energy power supply and power electronic equipment connected to power system, the electrical characteristics of power frequency have changed, and the performance of current relay protection has declined, which can not meet the requirements of new power system. The principle of transient-based line protection can realize high-speed and accurate fault identification inside and outside the area with the help of fault information contained in high-frequency quantity, which is not affected by power frequency information. It is a very promising research direction. Based on the research of transient quantity at home and abroad, this paper comprehensively and systematically combs the transient quantity from the application background and method level, analyzes the current research status of transient quantity protection, discusses the characteristics and problems of current protection principle, and prospects the direction of futural development.