Wideband Modeling, Field Measurement and Simulation of a 420 kV Variable Shunt Reactor

A 420 kV gapped-core five-legged variable shunt reactor is modeled in the frequency range 5 Hz-10 MHz based on frequency sweep measurements and curve fitting. Comparison with time domain measurements at reduced voltage shows that the model can accurately predict the transient behavior of the shunt reactor, both for impinging overvoltages and circuit breaker transient recovery voltages. Among the observations is that mutual coupling between the phases leads to a beat phenomenon in the reactor voltage following disconnection. Representing the shunt reactor by an LC parallel circuit leads to unrealistic results for steep-fronted incoming waves and high-frequency oscillating overvoltages, and for the attenuation of the transient recovery voltage following disconnection.