A New Concept in Power Circuit-Breaker Design Utilizing SF6

The type of breaker described in this paper combines many of the best features of other types of breakers and eliminates many of their disadvantages. An economical breaker has been designed based on the use of a building-block type of interrupter which lends itself to extension to a line of breakers. The mechanical interconnection of all contacts and the provision for through-type current transformers are both extremely desirable features which are generally obtained with dead-tank type breakers. The use of SF6 gas as an interrupting medium offers these distinct advantages: 1. Low breaker height and small floor area requirements permit installation in existing or conventional substation structures. 2. Demonstration of shock or noise during fault interruption is negligible. 3. Light weight keeps down the cost of installation. 4. Foundation cost is low because of light weight and negligible impact loading. 5. Maintenance cost is low and the time interval between inspection periods is longer. 6. Complete interrupter unit is readily and quickly removable for inspection or maintenance.