Application of thyristor in auto-tuning arc suppression coils

There are several means of grounding in electrical utility systems. Its main goals are limitation of transient line-to-ground overvoltages and the magnitude of the ground-fault current. An auto-tuning arc suppression coil (ATASC) is the important equipment in a resonant grounded system. The application of thyristor brings a very fast response speed to the different types of ATASC. It limits single-phase-to-ground-fault current in time and promote the grounding arc to self-extinguish. The TSC-type ATASC can realize the ideal tuning: it is in farmost off-resonant state in order to ensure lower neutral voltage under a normal system, and is tuned to the resonant state when a single-phase-to group fault appears. The tests of the TSC-type ATASC in simulation and the operation experience on the spot show its acceptable performance: firstly, it can limit the ground-fault current very low; secondly, its response time is very short; thirdly, it can measure the total capacitive reactance of the system-to-ground accurately.