Flexible High-Speed Load Shedding Using a Crosspoint Switch

Industrial load-shedding systems must address electric power system stability criteria as well as industrial process operations requirements. An effective industrial load-shedding system must provide a method to increase survivability of both the electric power system and the industrial process being powered. With intelligent crosspoint switches, the communications system can be fully supervised to prevent false load-shed signals and communications outages from causing false trips. This paper examines the concept and application of highspeed crosspoint switches to implement load shedding in an industrial plant setting. This design is currently being installed in an oil refinery and uses a load-shedding processor, protection logic processors with crosspoint switch functions, microprocessor protective relays for status input and analog quantities, and a power management system for operator load table inputs. The load-shedding scheme uses a substation-grade computer to process the current state of the power system (e.g., generation, load, topology, etc.) and write the load-shed table into three crosspoint switches. Several contingencies are defined in relay logic that may trigger load shedding, including generator trips, utility tie-line trips, bus-tie breaker trips, and underfrequency conditions