Abstract: As the GIS overhaul progressed and the upcoming retrofit of protection device for generatortransformer unit in Dongfeng Power Plant, it is more important to synchronously implement the duple configuration of breaker operating circuit and the application of related circuits at the foundation of achieving duple configuration of main equipments. The main problems existing in 220kV breaker operating circuit of Dongfeng Power Plant, such as DC operating power supply, tripping prevention, etc., were researched, the retrofit scheme of 220kV breaker operating circuit has been investigated, and the substantial suggestions were proposed in this paper.

Key words: 220kV breaker, duple, DC operating circuit