Utility experience of commissioning controlled switching devices on transmission shunt reactors

摘要

Shunt reactors are key components on transmission systems for voltage control. They are switched frequently by system operators depending on the system voltage requirements. Unlike normal loads which have a power factor close to unity, shunt reactors have a phase angle difference of 90° between the voltage and current. Therefore, switching present's difficulties for both system components and the reactor circuit breaker. Long dc offsets in the current waveform occur during energization and the potential occurrence of re-ignitions across the separating circuit breaker contacts during de-energization, result in chopping over voltages across the shunt reactor. This paper focuses on the benefits of the installation of two 50 Mvar shunt reactors on major city's 220 kV transmission system and how controlled switching can mitigate any negative impacts to the system or plant that can arise during switching.