IEC 62146-1:2013 is applicable to grading capacitors used on circuit-breakers. Their function is to control the voltage distribution across the individual interrupter units of a multi-break circuit-breaker. Grading capacitors can also be used in parallel to the interrupter unit on single break circuit-breakers to modify the Transient Recovery Voltage (TRV). The grading capacitor is a sub-component for the circuit-breaker and shall be specified in accordance with the circuit-breaker specifications. This standard applies to grading capacitors falling into one or both of the following categories for:
- mounting on air-insulated circuit-breakers;
- mounting on enclosed circuit-breakers (for example immersed in SF6, in oil, etc.). The testing for each of the above applications is in some cases different. The object of this standard is:
- to define uniform rules regarding performances, testing and rating;
- to define specific safety rules;
- to provide a guidance for installation and operation. Keywords: grading capacitors, circuit-breakers