The use of voltage regulators in power systems with arc-suppression coils

There is renewed interest in the use of arc suppression coils in high voltage power distribution systems. In existing distribution systems there is a widespread use of two pole mounted single phase auto-transformers connected in open-delta configuration to provide inline three phase voltage regulation. It has been shown that when this arrangement is used in a power system equipped with an arc suppression coil very high voltages can exist. A proposed solution is to use three, pole mounted, single phase auto-transformers connected in a closed delta arrangement. The use of three single phase auto-transformers in conjunction with an arc suppression coil is analysed in detail and the effect of the ratio of one of the transformers being out of step with the other two is assessed.