An Analysis of Extraordinary Oscillation of Potential Transformers

A simulation model of extraordinary oscillation in potential transformers (PT) was studied to determine conditions for its occurrence and countermeasures. The extraordinary oscillation is analyzed by solving the simultaneous equations derived from the circuit state equation by the harmonic balance method. Addition of a damping circuit on the PT side, or of a ground compensating capacitance on the system side, are suggested countermeasures, but the analysis results indicate that it is possible to introduce a rational setting method.