Study on a High Reliability Power Supply Scheme for Distributed Control System of Nuclear Power Plant

Abstract Distributed Control System (DCS) is regarded as the “brain” of nuclear power plant due to its function required in guarding nuclear safety. Power supply system is vital to supply electric power for DCS to maintain normal operation. Distribution design requirements of DCS power supply system are discussed firstly on analyzing the requirements of IEEE, IEC, etc. Combining with the comparative analysis of power supply schemes of DCS system in typical nuclear power plants based on CPR1000, AP1000 and EPR, key factors restricting the reliability of DCS power supply system are analyzed based on relevant design rules and standards in this paper. The method of improving the reliability of DCS power supply system is explored by analyzing the type of power supply, system design, equipment selection and design of electrical raceway. Thus a new high reliability power supply scheme for DCS system is presented based on mature equipment manufacturing technology. The scheme enhances the reliability, stability and flexibility of the distribution system by reducing the converting process on distribution path, increasing the design of cross-tie between divisions, and making full use of the advantages of DC distribution system. Through system operation analysis, equipment analysis and fault response analysis, this paper discussed the high reliability and feasibility of the new scheme, providing a new research direction for the design of DC system in nuclear power plant.