The research of power system restoration is an important subject to ensure the fast, safe and stable restoration of power fault area. Overvoltage verification during power line restoration is the key step to ensure the feasibility of power service restoration scheme. In order to solve the problem of overvoltage in the process of power service restoration process, a detailed simulation model is established by using the simulation software MATLAB/Simulink to study the influencing factors of the overvoltage amplitude at the end of the line when the backbone-grid restores power supply. A large number of simulation results show that the length of unloaded line and non-simultaneous closing of the three phases and asynchronous close of circuit breaker have significant influence on the amplitude of overvoltage at the end of transmisson line. Based on the simulation results, considering the characteristics of the backbone power supply system, the effect of load closing at the end of the line on reducing overvoltage is studied. The results show that proper load closing at the end of transmission line can not only effectively reduce the transient overvoltage at the closing moment of unloaded line and suppress the power frequency overvoltage at the end of line, but also make the simulation waveform more stable and more conducive to eliminating burr phenomenon through load control when switching unloaded line.

MATLAB/Simulink,power supply recovery,Overvoltage,Closing no-load circuit,Load calculation,MATLAB/Simulink