Available at: https://digitalcommons.calpoly.edu/theses/459
Date of Award
MS in Electrical Engineering
Motor Operated Valves (MOVs) are electro-mechanical components used to isolate, divert, or introduce fluid flow. The use of microprocessor relays for actuator motor electrical protection within nuclear power plants is the focus of this thesis and is implemented by providing a new and enhanced protection scheme that provides the adequate conservatism necessary to ensure valve operation while still maintaining electrical safety and continued operational availability. The comprehensive protection scheme is designed around an advanced microprocessor relay that has the ability to simulate the thermal overload conditions of a motor operating into a destructive thermal region. Through laboratory testing, the validity of this new protection scheme is tested using a simulation of common MOV degradations. Finally, this thesis addresses the design from a licensing basis perspective that follows Nuclear Regulatory Commission (NRC) guidance on the use of MOV thermal overload protective devices.