Utilization of time varying event-based customer interruption cost load shedding schemes

Load curtailments occurring under emergency conditions can have significant monetary impacts on the system customers. Customer satisfaction is becoming increasingly important in the new deregulated electric utility environment, and the customers in some jurisdictions are beginning to receive monetary compensation for power supply failures. Minimizing the customer interruption costs associated with a load curtailment event is an important factor in maintaining customer satisfaction. Customer interruption costs depend on many factors such as the customer types interrupted, the actual load demand at the time of the outage, the duration of the outage, the time of day and the day in which the outage occurs. This paper focuses on incorporating these interruption cost factors in a load shedding strategy. The load shedding algorithm was developed using an approximate event-based customer interruption cost evaluation technique to identify and determine the priority of the distribution feeders on a given bus during an emergency. The developed algorithm incorporates a time dependent feeder cost priority index (FCP). The optimum load shedding set determined using the FCP is a feeder or group of feeders that meet a capacity deficiency, and result in the lowest customer interruption cost for the specified emergency situation. This paper illustrates the algorithm development for a load shedding scheme and demonstrates the utilization of the technique on a sample load bus.