Patent ID: 8824116

Claim:
A method to determine the end-of-life of a vacuum interrupter, the method comprising: for each fault current detected, monitoring at least one parameter associated with the fault current to be interrupted or an operation of the vacuum interrupter to interrupt the fault current; using the at least one parameter to determine a single operation percent life consumed value for the vacuum interrupter, the single operation percent life consumed value being associated with interrupting the fault current; determining a cumulative percent life consumed for the vacuum interrupter, the cumulative percent life consumed being an accumulation of each of the single operation percent life consumed values corresponding to each of the detected fault currents, wherein the at least one parameter comprises a parameter selected from the group of parameters consisting of: a pre-interruption RMS fault current; a pre-interruption RMS fault current with DC offset removed; an asymmetric value of the most positive peak of the cycle of current preceding the fault interruption; an asymmetric value of the most negative peak of the cycle of current preceding the fault interruption; a fault current interruption clearing time; an operation number; total number of operations and a predetermined number of operations.