DEVELOPMENTS IN THE SIMULATION OF LONG-DISTANCE SINGLE-POLE-SWITCHED EHV SYSTEMS.

The simulation of secondary arcing is important in relation to the design of single-pole-switched EHV systems; but, until recently, it has not been possible to simulate this complex phenomenon. The paper extends earlier work on digitally simulating short uncompensated systems employing single-pole autoreclosure (SPAR) to long-distance applications. Work performed to characterise the extinction processes associated with secondary arcs in long-distance applications is reported. The new methods developed are employed in the simulation of a 500 kv application similar to the Winnipeg-Twin Cities interconnection, and a comparison with the results of some actual fault-throwing tests is made. Results of studies of conventionally compensated utransposed applications are summarized.