Short-Circuit Tests with Rapid Reclosing on the 220-Kv Mettlen-Lavorgo Line [includes discussion]

Before the 220-kv Mettlen-Lavorgo line was finally put in service, the protection devices and the circuit breakers of the 100-kilometer (km)-long 220-kv transmission system with grounded neutral point were tested for rapid reclosing with short-circuit arcs. The tests described here demonstrate the trouble-free performance of high-speed distance relays, air-blast circuit breakers, and the accompanying reclosing equipment. In the case of the single-pole ground faults, the residual arc was extinguished after, at the most, two periods. No restrikes occurred with a dead time of more than 0.22 second for the 3-pole and 0.45 second for the single-pole interruptions, and the power supply could be continued.