GB1263733A - Device for the synthetic testing of the breaking capacity of high-voltage power circuit-breakers - Google Patents

Abstract

1,263,733. Testing switches. LICENTIA PATENT-VERWALTUNGS-G.m.b.H. Jan. 31, 1969 [Jan.31, 1968; Feb.28, 1968], No.5460/69. Heading G1U. In an arrangement for the synthetic testing of the breaking capacity of a very high-voltage power circuit-breaker PS, there is superimposed on a transient voltage developed across the tested breaker after a test current interrupted thereby has become zero and commencing before the transient voltage reaches its maximum, an additional transient voltage such that the resulting combined transient voltage matches the test voltage necessary for the tested breaker. The arrangement comprising a high-voltage oscillatory circuit III for supplying both the additional transient voltage and an auxiliary current which includes a current frequency determining capacitor C H, a normally closed auxiliary breaker HK which is also connected in a circuit containing the tested breaker, and voltage determining elements REK, CEK in parallel with the auxiliary breaker HK. As the test current to be interrupted by the tested breaker approaches zero, an auxiliary current with the same polarity is applied to the tested breaker by the high-voltage oscillatory circuit, this auxiliary current becoming zero at the moment when voltage superimposition is required to commence, at which time the auxiliary breaker HK is opened and the capacitor CH in the high-voltage oscillatory circuit is short-circuited, such that the transient voltage determining elements REK, CEK initiate the generation of the additional transient voltage. In one embodiment Fig. 1, high current is applied to the breaker PS under test from a transformer T via an auxiliary breaker HS in a circuit I. As a current zero is approached HS is opened at time to to isolate the high current and a spark gap F1 fired to apply a transient high voltage from an oscillatory circuit CE, LS to the test breaker (circuit II). Spark gap F2 is then fired at time t 1 so that current from a source capacitor CSK is applied to charge the capacitor CH in the high voltage oscillatory circuit and auxiliary current flows through the tested breaker. The tested breaker PS is then opened at time t 2 to interrupt the auxiliary current. F3 is then fired at time t 3 and HK is opened so that the auxiliary transient voltage across capacitor CEK is added to the transient voltage from circuit II. In a second embodiment Fig. 2 (not shown) the auxiliary breaker HS and first high voltage circuit are dispensed with, and the breaker HK with its associated components is included in the series path between the current source and the test breaker. Another arrangement Fig. 4 (not shown) is similar to that of Fig. 1 but the breaker HK and its associated components is in series with and on the earth side of the test breaker relative to the current source.