Analysis on influences of transient over-voltage by vacuum circuit breakers operation in 35kV PV-LVRT experiment

Vacuum circuit breakers switch off shunt reactors, when the low voltage ride-through (LVRT) experiments are performed in Photo-voltaic (PV) system. Transient over-voltage is occurred and gotten a high amplitude in the experiments. It would cause external insulation breakdown of reactor and equipment damage. Base on circuit theory, this paper focused on factors which impacted on the transient over-voltage in the 35kV PV-LVRT experimental system. And then according to 35kV LVRT experimental line, a simulation model of experimental system was established in ATP/EMTP. The simulation results indicated that the closure value of vacuum circuit breaker the size of invested short-circuit reactance and the size of shunt capacitor were major influencing factors on the transient over-voltage caused by vacuum circuit breaker operation. A 0.1 μF shunt capacitor and a 100Ω shunt resistor could effectively reduce the peak value of transient over-voltage what were set to test point in the experiment.