Analysis for the Effect on Voltage Sag of Safety Bus as Electrical Operating Modes in Nuclear Power Plants

When electrical transients take place in onsite power system of nuclear power plants, the voltage of safety bus can be affected, as a form of voltage sag, by the transients. The safety buses in nuclear power plants have a role of power supplying to essential loads for safety shutdown of reactor. If voltage sag of the safety bus occurs and impact on the safety features is existed, the risk of nuclear power plants is increased. Therefore, it is necessary to analyze the effect on voltage sag of safety bus due to electrical transients as operating modes of power systems in nuclear power plants. This study performed that the phenomenon of voltage sag on the safety bus due to various transients as electrical operating modes is simulated and analyzed.