The Oil Circuit Breaker Situation from an Operator´s Viewpoint

This paper is an outline of the oil circuit breaker situation from the operator´s standpoint, particularly with reference to interrupting duty, as it appears today to the author. It is not an original study, but rather an assembly of previously existing information, and is arranged by topics with a view to bringing out amount of discussion, in the hope that it may result infurther clarifying the very complex problem of interrupting electric currents. The topics taken up are as follows: I Factors determining interrupting capacity, namely, intensity and duration of the arc. II-III Essential features of breaker design and their functions. IV Factors affecting interrupting duty, with especial emphasis on effect on same of system and fault grounding conditions. V Relations between interrupting ratings and costs. VI Status of interrupting ratings with reference to maximum nature of such ratings and facts upon which they are based; relative ratings on different operating duties and desirable modifications in method of rating. VII Applications, particularly possibilities for improved practise in future, and necessity of adequate maintenance on all breakers in service.