Phase-shifting transformer and protection system of phase-shifting transformer

摘要

In a phase-shifting transformer, a stabilizing winding is connected to a regulating transformer in a delta connection form, a regulating winding is connected to in parallel transmission lines and a tap winding supplies a predetermined voltage to an exciting winding of a series transformer. When the current ratio and the phase between the differential current between the stabilizing winding current and the regulating winding and the tap winding current exceeds a predetermined value, it judges an internal fault in the regulating transformer. The phase-shifting transformer comprises a third winding in addition to the tap winding and the regulating winding. In the phase-shifting transformer, the internal fault in the regulating transformer can be surely detected and thereby the phase-shifting transformer can be protected.