Patent ID: 7323852
Filing Date: 2008-01-29
Classification: G05F

Abstract:
1. In a system which includes a load tap changer (LTC) having a plurality of windings, selected ones of which are selectively coupled to one of the primary and secondary of a power transformer in order to regulate the output voltage of the transformer and wherein the LTC includes a plurality of taps physically and electrically connected to and along the windings and contact is selectively made to the taps to increase or decrease the output voltage of the transformer by moving a contacting element from a tap to another tap along the LTC winding and wherein the power transformer and the LTC windings are placed in a main tank and the taps are placed in an LTC tank, and wherein the temperature in the main tank is monitored by means of a first probe and the temperature in the LTC tank is monitored by means of a second probe, the improvement comprising: means coupled to said first and second probes for sensing the temperature differential between the main tank and the LTC tank and determining if the LTC tank temperature exceeds the main tank temperature for a period of time exceeding a specified time period and for sensing the rate of change of the temperature differential and determining if it exceeds a predetermined value.