GB919622A - A testing arrangement for high-voltage circuit-breaker - Google Patents

Abstract

919,622. Testing circuit-breakers. LICENTIA PATENT - VERWALTUNGS - G.m.b.H. Dec. 4, 1959 [Dec. 8, 1958], No. 41270/59. Addition to 855,970. Class 37. In a testing arrangement for high-voltage circuit breakers as described in the parent Specification of the kind comprising a circuit for the supply of a high alternating current to the breaker contacts to be tested, and a circuit for supplying a high voltage to the breaker contacts when the latter have reached their open position, and including in the high current circuit a full wave rectifier and an inductive reactance, an auxiliary breaker is included in series with the breaker to be tested which auxiliary breaker is so designed that it starts to open its breaker gap only during the last high-current half wave and interrupts the high-current circuit at the end of this half-wave. An alternating current generator G provides a high current through transformer T to high current circuits I, II including circuit breakers S1 S2 respectively, mechanically actuated in synchronism with the generator frequency and adjusted in such a manner that the rectified current i<SP>1</SP>k is prevented from reaching zero value. Connected across the breaker Sp to be tested is a high-voltage circuit III comprising capacitor C, switching spark gap F and oscillatory choke L. An auxiliary circuit breaker S h is used to complete the high-current circuit before the testing operation commences and is designed to open the high-current circuit just before the high voltage is applied, i.e. during the last half-wave of the applied current. To achieve this the circuit breaker S h may be a high speed gas-blast circuit breaker having a fixed annular contact and a pin-shaped movable contact which passes through the annular contact whereby the movement of the movable contact can be initiated before the beginning of the last highcurrent half-wave and the moving pin-shaped contact made to leave the annular contact at the instant when the last half-wave begins. Alternatively, the fixed contact may be designed as a resilient contact. In order to avoid distortion of the current i<SP>1</SP>k at the end of the last high-current half-wave due to one of the two switches S1 S2 already trying to connect in a fresh high-current half-wave, the switches may be interrupted, if they are mechanical switches, by displacing their fixed contacts so that the movable contacts can no longer reach the fixed contacts, or, if they are gas-blast circuit breakers, the extinguishing gas blast may be increased or a more effective arcquenching medium may be directed into the breaker gap after the last high-current halfwave.