Enhanced Fault-Location Scheme for Double Wye Shunt Capacitor Banks

Determining the location of internal failures in shunt capacitor banks (SCBs) helps to expedite their repair process and, thus, increase the time during which the power system benefits from this crucial component. This paper elaborates on fault location for a common configuration in high-voltage SCBs, which is the double wye connection (Y-Y). The neutral current unbalance protection is adapted to suit the development of an algorithm that detects the location of internal failures in ungrounded and grounded Y-Y SCBs. The proposed method is capable of detecting consecutive failures, and also can mitigate gradual capacitance and temperature change effects. Both internally fused and fuseless banks are considered in the proposed technique. The presented fault-location method is further enhanced by detecting the number of failed elements. Simulations are performed using PSCAD and MATLAB. The results validate the proposed method performance under pre-existing internal unbalances, system voltage unbalance, and faults in the grid. Illustrative simulation scenarios are provided to show the application and significance of the proposed method properties.