Fuse Protection for Power Thyristors

A study of the behavior of current limiting fuses and of their effectiveness in protecting power thyristors is presented. Mathematical models simulating the prearcing and arcing characteristics of the fuse are described and used for analog computer evaluations. The junction temperature response of a thyristor to surge currents is analyzed with the aid of a further model. Finally, the fuse and thyristor simulations are coupled for a survey of the combined system. From this, a practical fuse/thyristor coordination rule is developed.