A study of capacitor element failures in high voltage Shunt Capacitor Banks

Internal failures in Shunt Capacitor Bank (SCB) units render trips from unbalance protection to prevent from further damage to the equipment. Fuseless and internally fused capacitor cans are the dominant technologies in power capacitor design, which do not provide external indication for units with failed elements. Modeling and study of internal failures enable intelligent monitoring and reduction of SCBs unscheduled outages. Accordingly, the major part of this paper models transients generated because of element failures in SCBs. Then by applying the models, a recent fault location method is evaluated using electromagnetic transients simulation in PSCAD and fault location analysis in MATLAB. Results show immunity of the fault location outputs to the imposed transients. Finally for a more selective fault location method and further reducing SCBs outage time, the paper suggests future works on offline spectral analysis of the oscillography records that are triggered by online fault location functions.