An operational simulator for testing EHV and MV protective relays

The development of protection systems for EHV and MV transmission makes it necessary to update equipment testing devices. New digital relays operate faster and cover an increasingly broad frequency spectrum. Their acceptance and routine tests, the analysis of operating incidents and even the study of new principles require a tool which can accurately generate transient currents and voltages over a large bandwidth. Therefore Electricite de France (EDF) has developed an open loop digital transient network analyser tool (DTNA). The DTNA allows tests of the EHV transmission protective relay. In view of the complexity of the transient modelling in the DTNA, it can appear that the integration of this code in the environment of a protection-unit test laboratory presents major difficulties. Nothing of the kind, since the development of the DTNA from its original design integrates the automated management of the test databases, the man-machine graphical interface, the plotting and the post-processing of the simulation results, which now allows an operator used to former analogue test benches to use the DTNA without any difficulty. The introduction of new models (voltage generator with a nonlinear frequency, a nonlinear amplitude, and a superposition of harmonics; hysteresis and remanent models for transformers) allows MV transmission protective relay tests