Digital Protective Relaying and Testing Facilities: Present Research at Electricite de France

Abstract

Abstract Using digital techniques in EHV substations makes it possible to reconsider protection and control functions. At EDF, studies have been carried out for several years in this field. This paper describes an experimental digital distance relay based on a multiprocessor architecture and states some differential protection algorithms which have been developed to cope with the increasing complexity of transmission networks (general use of double-circuit lines, tappings, high nominal load currents due to increasing section of conductors…). In order to test the new relays which are getting faster and faster as well as to examine carefully new protection principles which induce complex algorithms. EDF has developed a digital simulator based on a powerful minicomputer. The main principles of the network transient simulation program are stated. A digital fault recorder has also been designed to collect actual data on the EHV system. With a 2 kHz bandwidth, this device allows a good knowledge of transient phenomena. These two complementary tools are presently used to test new relays and to validate new protection algorithms.