The Research On Overvoltage In Switching Off Shunt Reactors Of 35kV Vacuum Circuits Breaker

The paper researches the problem of switching overvoltage in Tianjin area, which is produced by vacuum circuit breaker in the process of switching on and off the shunt reactor. First, this paper states an overview of the present research status on vacuum circuit breaker, and analyses the mechanism of switching overvoltage produced by vacuum circuit breaker when the shunt reactor is switched on and off, then this paper studies the present situation of shunt reactor installation in several cities and the production status of parts of manufacturers. Based on the fact of Tianjin area and study results, this paper builds a system model and formulates three methods to emulation, which are demonstrated by the field experiments. Also the paper discusses several kinds of overvoltage protection equipments. According to emulation and field test, the paper studies the feasibility to the overvoltage protection programs, and thus the best protection program has been achieved: A group of RC is installed on bus, and a group of RC is installed on shunt reactor, and a group of three-phase combined metal oxide surge arrester without series gap is installed on load-side of the circuit breaker which helps with phase-to-phase protection of the breaker. The paper carries out comprehensive analysis of the problem of switching overvoltage produced by vacuum circuit breaker in the process of switching on and off shunt reactor, and puts forward several measures to suppress the switching overvoltage produced by vacuum circuit breaker in the process of switching on and off shunt reactor. The switching overvoltage suppression programs have been applied to down-to-earth projects of newly-built substations as well as substations in operation in Tianjin area, and indeed the programs avoid switching overvoltage coming into being and reduce the risks of electric equipments damage offering both economic and social benefits.