When using vacuum circuit breaker to switch shunt reactors

the current chopping

overvoltage with repeatedly renewed and other hazards will come along. Those hazards do destabilize power system operation. Based on ATP-EMTP

this paper firstly simulates the actual operation of substation

and it is found that in the bus side

load side and a reactor side there are serious phase-to-ground overvoltage and phase-to-phase overvoltage. Then combining the type and severity of the overvoltage

different protection devices are used to simulate the protecting effectiveness. Finally

according to the actual operation of substation

overvoltage conditions after applying different protection schemes are simulated and computed. Research results indicated that

the overvoltage induced by switching off shunt reactors can reach two times higher than normal overvoltage induced by single phase cut-off;overvoltage between phase to phase is obviously higher than that between phase to ground; mounting two-way RC overvoltage protection on the load side of the draw and the reactor side should be the best approach to guarantee the security and stability of the substation

which is able to lower the overvoltage by 50% to 69%.