Test & Study On Switching No-load Overhead Lines By Alternating-current High-voltage Circuit Breaker

When switching the no-load overhead lines by alternating-current high-voltage circuit breaker which is a kind of daily operations in electric power system , over-voltage is probably bringed out and insulating property of the electric devices is breakdowned sometimes, especially, when occuring re-strike. The main purposes that the tests on switching line-charging current are performed in the laboratory are assessing re-strike performance of circuit-breakers. According to the test results, the design of the circuit-breaker is optimized and re-strike performance is improved.In this dissertation, firstly, characteristics of no-load overhead line and processes of switching no-load overhead line by circuit-breakers are analyzed, then , transient recovery voltage across circuit-breaker are calculated emphatically and the factors of affecting transient recovery voltage are analyzed. Initial recovery voltage and peak recovery voltage across the circuit-breaker have an essential affect on re-strike. For assessing performance of circuit-breaker, the higher inductance and lower inductance must be considered at the same time when testingAccording to theoretic analysis, the directly test circuit on switching the no-load overhead by high-voltage circuit breakers of rated voltage 252kV and below, in compliance with the correlative standard JB5871 and the test devices, and the test circuit parameters have been calculated and the many testes have been carried out. For the circuit-breakers of rated voltage 252kV up, the synthetic test methods are introduced according now condition because of the limitation of the transformer short-circuit capacity. The correlative prescribes on switching line-charging current in GB/T1984-200X "Alternating-current High-voltage Circuit-breaker" are discussed according to the test results and theoretic analysis .