Intelligent reclosing for overdutied breakers

The increase in fault current magnitudes above the derated breaker interrupting capability requires the use of circuit breaker replacement, current limiting devices, changes in system configuration, etc. All the above solutions to the overdutied breaker problem are very expensive. This paper demonstrates that by applying a combination of breaker trip with fault current control and adjusting the number of reclosing shots as a function of the fault current magnitude, breakers overdutied by fault currents between the derated and 100% of the breaker interrupting capability do not need replacement. This approach was applied in New York State Electric and Gas (NYSEG)´s system for about 30 overdutied breakers