Patent ID: 8729906

Claim:
A method of monitoring partial discharges occurring in an electrical system, the method comprising: defining a low trigger level and a high trigger level, the low and the high trigger levels being amplitude levels for electrical pulses, wherein the high trigger level is a higher amplitude than the low trigger level; defining a minor time frame period; monitoring at least one phase of the electrical system for an occurrence of a pulse within the minor time frame; detecting a peak amplitude of a pulse occurring in the electrical system within the minor time frame; determining if the detected peak amplitude of the pulse exceeds the lower trigger level and/or the higher trigger level; assigning a pulse number to the pulse if the peak amplitude of the pulse exceeds the lower trigger level and/or the higher trigger level; capturing the pulse, or information associated therewith, if the pulse number associated with the pulse is less than a predetermined pulse number threshold in the minor time frame; applying a moving time trigger offset, such that: if a pulse exceeds the low trigger level but not the high trigger level and the pulse number equals a predetermined number of pulses then recording the time value within the minor time frame at which this occurs and ceasing to capture pulses exceeding the low trigger level but not the high trigger level until after this time value in a following minor time frame; and resetting the time value of the moving time trigger offset to zero and starting to capture pulses for the next minor time frame for pulses exceeding only the low trigger level after the moving time trigger offset value equals the value of the minor time frame; and storing the captured pulses in a memory device.