COMPUTER-SIMULATION OF PHENOMENA ASSOCIATED WITH HOT GAS IN PUFFER-TYPE GAS CIRCUIT-BREAKER

To analyze hot-gas flows in puffer-type gas circuit breakers (GCBs), a program was developed by adding functions for dealing with opening process, gas compression, and arcing to an axially-symmetric compressive fluid analysis program. Accuracy of the program is proved by comparing the results of computation by this program with the results of two different tests: the observation of hot-gas backflows by using the Schlieren method and the measurement of breakdown voltage drops resulting from hot gas generated by current interruptions. The results of both tests show trends similar to calculated results obtained by simulating the tests, proving that this program is applicable to interruption phenomena associated with hot gas to a certain extent. The program is applied to the calculation of pressure rise phenomena in a puffer chamber caused by hot-gas backflows and dielectric strength to ground in a tank-type GCB. The program is expected to be useful as a means of estimating test results.