Single-Pole Switching-A Comparison of Computer Studies with Field Test Results

The electrical characteristics of a 150 km 500 kV transmission line during single-pole switching is simulated on a hybrid computer. A time dependent arc simulation aids in the study of the voltage occurring across the arc and the recovery voltage during single-pole switching. The accuracy of the simulation is verified by comparison with field tests. The simulation is also used to investigate the transient recovery voltage following a bolted, sudden release fault. This investigation reveals that the transient recovery voltage is markedly larger than the steady-state value and that, for a normal three cycle clearing, it is a function of the time that the fault occurs. The simulation of the transmission system established in this paper may be used to advantage in determining the dead time necessary to insure extinction of the secondary arc current. Moreover, the results set forth should serve as guides for engineers designing systems for single-pole switching.