Investigation of Ferroresonance Causing Sustained High Voltage at a De-Energized 138 kV Bus: A Case Study

Ferroresonance causes overvoltage and excessive current flow on potential transformers (PT), which can cause substantial damage to PTs and interrupt the power system normal operation. In this article, a sustained overvoltage event on a de-energized 138 kV bus after the circuit breakers were opened to clear a phase A to ground fault at a Canadian transmission utility power grid is investigated. The power systems computer aided design (PSCAD)...