Arc-suppression coil based on transformer with controlled load

In order to develop an arc-suppression coil (ASC) with rapid and continuous regulation and limited harmonic output in neutral resonant grounding power system, the ASC based on transformer with controlled load is proposed. The voltage source PWM inverter works as the secondary load of transformer, the reactance of the ASC can be regulated arbitrarily through controlling the inverter output current. Large capacity ASC can be realised by adopting the transformer with multiple secondary windings. An improved injecting variable-frequency signal method is adopted to detect the distribution network line-to-earth capacitance accurately. Three-phase dynamic simulation experiments have been carried out on the 800 kVA/10 kV prototype, the experimental results validate that the arc-suppression apparatus has the characteristic of high precision in capacitance detection, wide compensation range, fast response and few harmonics.