Analysis of SF6 Circuit Breakers Failures Related to Missing Current Zero. Part II.

Abstract

This paper describes aspects of switching capability of 500-750 kV SF6 circuit breakers during breaking of aperiodic current (DC component) resulting in such phenomena as missing current zero. It is described two cases of circuit breaker making operation namely making in maximal voltage and making near zero voltage. The analysis of SF6 live tank circuit breakers 525-750 kV failures in 1,150 kV “Altai” substation, 750 kV “Novobrianskaya” substation and 500 kV “Agadyr” substation based on current and voltage oscillograms is given. The review of 126-750 kV puffer and auto-puffer SF6 circuit breakers failures with corresponding time to first current zero and resulting effect is presented. The general countermeasures associated with design stage of circuit breaker and its relay protection improvement as well as the other effective methods against prevention of circuit breakers failures related to missing current zero are given. This paper is the second part of the present research.