Research On The Influence Of Fast Power Switch On Relay Protection

In recent years, with the increase of load capacity and the requirement for powerreliability, the quick power-supply-switching device is applied to major industry, replacing thetraditional automatic bus transfer equipment. Because special power system has specialstructure and type of loads, it is of great significance to simulate the process of power switchusing quick power-supply-switching device and analyze its influence on power system,especially on relay protection.Firstly, according to the concrete structure and parameters of the corporation power gird,the simulation model is set up. Because the operation modes of Tianjin SINOPEC powersystem are complex, this paper chooses three typical modes to conduct the study. In everyoperation mode, the simulation of power switch process is conducted respectively on fasttransfer mode, in-phase transfer mode and residual voltage transfer mode. The changingregularity of switching impact is obtained in different operation modes through comparativeanalysis. Meanwhile the deficiencies of current switching modes are indicated, and the switchcriterion of in-phase transfer mode is improved based on the theoretical analysis of powerswitch process. And it is verified by the simulation of Tianjin SINOPEC power system. Thesuccess rate of power switch can be increased through this modified method.Secondly, many sets of simulation data about impulse current and surge voltage areobtained through the numerical simulation of power switch process on different conditions.By checking the setting of protective relaying, the switching conditions and the relayprotection styles are pointed out, which are probably operated when power switches. Thenthis paper gets the key factors that influence the impulse current by theoretical analysis. Basedon above research, the regulatory measures of the quick power-supply-switching devicematching with relay protection are proposed to reduce the switching impact on power system.Through these measures, the impact of power switch can be effectively reduced, avoiding theoperation of relay protection. These measures can be applied to another power system.