Transient Recovery Voltage Assessment for 138kV Breakers with the New Addition of a Wind Farm

Increased short circuit current level due to rapid growth of power network could reach and possibly exceed the capability of existing breakers. An assessment study of existing breakers needs to be performed to guarantee the breakers can operate safely at present and also in the future. A new proposed wind farm is added to a nearby substation. One concern is how the wind farm impacts the substation power system. This paper presents the assessment of the substation power system and determines if transient recovery voltage (TRV) exceed the breaker capability. The assessment was carried out by digital simulation using PSCAD to analyze TRV waveforms. This paper presents the detailed setting-up of the digital model of the substation and surrounded power system. Based on the output, the peak values and rate of rise of the TRV waveforms can be determined. These values were compared with breaker ratings calculated by IEC standard 62271-100. The studies indicate that breaker TRV does not exceed the capability and the breaker can operate safely with the new addition of a wind farm.