三门核电主交流电源系统低压扫负荷继电器的电源优化

Power Supply Design Modification on Under-voltage Relay for Load Shedding in Main AC Power System of Sanmen NPP

低压扫负荷继电器在残压切换和备用柴油发电机投入带载负荷中担负着重要作用．继电器一旦失电，将可能会使电厂直接进入全厂失电状况。本文对AP1000主交流电源系统中低压扫负荷继电器的供电电源进行分析，从运行角度指出目前设计中低压扫负荷继电器可能存在失电的风险，进而提出了电源优化及实施方案。为后续机组及其他同类型电厂的低压扫负荷继电器的电源设计，提供一种思路。

The under-voltage relay for load shedding plays an important role in the process of residual power transfer and onsite standby diesel generator start and load sequence. If the power of relays is lost, the plant will enter into ＂station black-out＂ condition directly. According to the analysis of power supply for the under-voltage relay used in Main AC Power System （ECS） of AP1000 plant, the risk of loss of power for the relay exists from the view point of operation, the suggestion of design modification is also introduced in this paper. The paper suggested conceptual design for the subsequent and other similar plants.