Optimal design of autorecloser electromagnetic actuator

Following the successful development of a bistable electromagnetic switchge ar actuator for driving vacuum interrupters in an autorecloser, several MV switchgear companies have begun to develop similar actuators for use in aut oreclosers powered by primary lithium batteries. However, many of these act uators consume excessive energy in operation, adding undesirable battery co st to the equipment. A model is developed that enables these actuators to b e optimised in energy terms, since it simulates the electrical. magnetic an d mechanical effects seen by the actuator and their interactions. The model is a detailed lumped reluctance type. The lumped reluctances were defined after inspecting the results of the finite element analysis of a generic ac tuator. The model uses iteration routines to calculate the flux distributio n within it and an improved stochastic optimal method to obtain an optimal design, in terms of magnet cost and operating energy usage. Simulated and t est results are presented, and these show a close correlation.