The dynamic representation of protection systems

This paper presents a dynamic model of a protection system based on a differential feeder protection along with the primary power system. A commercially available relay is modelled and its functions explained. A general primary power system model structure that includes a fully integrated protection system model is discussed. The protection system model contains dynamic models of both the relays and the transducers. A technique will be described for developing an accurate dynamic model of a numerical protection relay using actual microprocessor codes from a commercially available relay. Finally, the practical application of the analysis under abnormal system conditions is demonstrated. Different faults are applied to the internal and the external regions of the feeder, and the response of the relays examined. (C) 2000 Elsevier Science Ltd. All rights reserved.