Main Protection Optimization Scheme for Generator Parallel Operation of Rotating Asynchronous Machine in Nuclear Power Plants

The Rotating Asynchronous Machine (RAM) system of a nuclear power plant provides a stable and reliable power supply for the control rod drive mechanism (CRDM) through two parallel generators. At present, the main protection of the generators in the RAM system is only configured with longitudinal differential protection, which cannot reflect the interturn short circuit fault and interbranch short circuit fault of the stator winding. Based on the characteristics of parallel connection of RAM generators in nuclear power plants, this article proposes a dual-generator split phase transverse differential protection and a dual-generator incomplete longitudinal differential protection. Through the internal fault set of the generator and the internal fault potential splitting model of the generator, the quantitative analysis of different main protection configuration schemes is carried out. It is concluded that the existing longitudinal differential protection and the incomplete longitudinal differential protection of two parallel generators can correctly reflect the vast majority of internal short-circuit faults. Finally, the dynamic experiment is carried out to prove the feasibility of the protection method in the actual unit operation.