Patent ID: 8575941

Claim:
An apparatus for identifying which phase of a capacitor bank of a first ungrounded shunt capacitor bank or a second ungrounded shunt capacitor bank has a faulted capacitor element, the apparatus comprising: a sampling circuit for sampling current or voltage signals associated with the first and second ungrounded shunt capacitor banks, and a microcontroller coupled to the sampling circuit to determine a compensated neutral point phase angle from the sampled signal, wherein the compensated neutral point phase angle takes into account an inherent current or voltage unbalance in the ungrounded shunt capacitor banks, said microcontroller including: a comparator to compare the compensated neutral point phase angle with a fixed reference phase angle to identify which phase of the first or second ungrounded shunt capacitor banks has the faulted capacitor element and to identify which of the first and second ungrounded shunt capacitor banks has the faulted capacitor element.