Effect of de-regulation on operation of electrical grid and nuclear power generating stations

In a nuclear power plant, offsite and onsite electric power systems are required to provide sufficient capacity and capability to assure that the containment integrity be maintained during power operation or in case of a postulated accident. Analyses must verify that the electric grid remains stable in case of loss of the nuclear unit, the largest other unit on the grid or the most critical transmission line and a change it due to deregulation would affect those analyses. Nuclear Regulatory Commission (NRC) staff ensures that the licensees maintain adequate voltages to the Class 1 E (safety) buses. If the operator has failed to restore adequate voltages, the Class 1 E buses should be automatically separated from the offsite power system and connected to the emergency diesel generators. Most utilities use on-line contingency analysis and the control centers notify them when the offsite power system in their nuclear plant is degraded. The control centers use load conservation procedures to provide the plant a stable offsite power system. The control centers have assured the NRC staff that the nuclear power plants are their preferred customers and that they will be provided with an adequate offsite power system even under reduced grid generation availability. This paper discusses the voltage stability, power transfer limits, reactive reserves, methods of improving voltage stability (such as superconductivity), load conservation procedures and effects of deregulation on nuclear power generating stations.