Reactor Switching Tests of an Oil Circuit Breaker Shiprock Substation Colorado River Storage Project February 16-17, 1966

摘要

Reactor switching characteristics of a 13.8-kv oil circuit breaker were investigated by a series of controlled point-on-cycle switching tests. Long clearing times (2.54 cycles on the average) result from high rates of rise of recovery voltage and from current chopping overvoltages. Laboratory model reactor switching tests demonstrated that breaker contact recovery voltages of 3.0 per unit for the first contact to clear and 3.46 per unit shared by the last two contacts clearing are to be expected, and that the application of suitable resistor-capacitor transient suppressors would be effective in reducing both the magnitude and rate of rise of recovery voltages. The effectiveness of the application of these transient suppressors was demonstrated during the field tests where clearing times were reduced to 1.65 cycles on the average (clearing achieved about two current zeros earlier than clearing without transient suppressors). A considerable reduction of oil carbonization and contact erosion is to be expected because of the reduced arc time and reduced total arcing period energy. The capacitor-resistor loading equipment on the reactor side of the tested breaker is to be continued in service for about a year to provide information for further evaluation in comparison to a similar breaker on an unmodified circuit. (Author)