IN-SITU FAULT DETECTION APPARATUS AND METHOD FOR AN ENCASED ENERGY STORING DEVICE

摘要

An apparatus and method for detecting a breach in an electrically resistive surface of an electrically conductive power system enclosure within which a number of series connected energy storing devices are disposed. The energy storing devices disposed in the enclosure are connected to a series power connection. A detector is coupled to the series connection and detects a change of state in a test signal derived from the series connected energy storing devices. The detector detects the presence of a breach in the insulating layer of the enclosure by detecting a state change in the test signal from a nominal state to a non-nominal state. The detector may comprise a pair of tap lines respectively coupled to adjacent opposing end energy storing devices of the series connected energy storing devices. A switch provides selective connectivity between each of the tap lines and the enclosure for the purpose of developing the test signal respectively on each of the tap lines. A voltage detector detects a state change of the test signals on the tap lines from a nominal state, represented by a voltage of a selected end energy storing device, to a non-nominal state, represented by a voltage that substantially exceeds the voltage of the selected opposing end energy storing device. Alternatively, the detector may comprise a signal generator that produces the test signal as a time-varying or modulated test signal and injects the test signal into the series connection. The detector detects the state change of the time-varying or modulated test signal from a nominal state, represented as a signal substantially equivalent to the test signal, to a non-nominal state, representative by an absence of the test signal.