A 161-Kv 10,000-Megavolt-Ampere Steel-Clad Impulse Circuit Breaker-The First of a Line of High-Capacity High-Voltage Circuit Breakers [includes discussion]

This paper describes the initial step in the development of a line of high-voltage high-capacity steel-clad impulse oil circuit breakers required to fulfill the increased interrupting duty requirements of the industry at 138 kv, 161 kv, 230 kv, and 330 kv. Primarily this paper describes the development of the circuit breaker required for the 161-kv 10,000-megavolt-ampere rating. The circuit-breaker design provides for the first time the impulse principle of interruption in a tank-type circuit breaker and in addition combines several of the proved features of modern high- and low-voltage outdoor circuit breakers. These elements are basically flexible enough to be extended readily to increased interrupting ratings and to higher and lower voltage levels. Complete electrical and mechanical design tests demonstrated that the circuit breaker meets all industry standards with ample margins of safety. Tests at the new switchgear development laboratory on all types of interrupting duty produced consistently short interrupting times over the entire current range. Various charging currents corresponding to the equivalent of up to 400 miles of 161-kv transmission line were switched with no restrikes. These tests have demonstrated that the design equalled the performance of the low-oil-content impulse circuit breaker and was flexible enough to provide the necessary starting point for designing an entirely new line of high-voltage high-capacity circuit breakers.