Improvement of high voltage switchgear reliability

The reliability and availability of MV and HV circuit breakers is essential to the fulfilment of power network failure elimination. Experience has shown that about a quarter of major failures are due to failure of circuit breaker auxiliary and control circuits. Another important cause of failures is faulty SF₆ density monitoring systems. The integrity of this parameter is fundamental in ensuring the apparatus´ dielectric rigidity as well as interruption of high fault currents. The last cause of major circuit breaker failures is the risk of failure of its mechanical parts. In order to solve these problems, the authors have undertaken the design of new low voltage auxiliary switchgear equipment with integrated state monitoring functions by making use of the new possibilities offered by appropriate digital equipment