Modelling of power-system protective equipment on analogue computers

The transient performance of protective equipment is simulated under easily controlled conditions by means of specially constructed models. The models are developed in such a way that parameter variation of the protective system is easily achieved. The primary-fault currents necessary for testing the developed models are accurately generated using analogue computers. The design and testing of the individual models are described, and the method of interconnecting them to form complete protective schemes is shown. The developed protective-scheme models are used for both electromagnetic-and static-relay testing. The performance of electromagnetic relays is simulated using the analogue computers, as direct testing of such relays is not possible owing to the low power levels available in the model. Direct testing of static relays is, however, possible. The results of a number of tests using the developed models are given.