On Two Fundamental Signatures for Determining the Relative Location of Switched Capacitor Banks

This paper describes two fundamental signatures of shunt capacitor bank switching transient phenomena from which one can accurately determine the relative location of an energized capacitor bank whether it is upstream or downstream from the monitoring location. Mathematical analysis of a capacitor bank energizing proves that: 1) the energized capacitor bank affects only the upstream reactive power flow and 2) at the energizing instant, the gradients (time derivatives) of voltage and current waveforms measured upstream from the capacitor location will have opposite signs. The reverse is true in that at the energizing instant, gradients of voltage and current waveforms measured downstream from the same capacitor location will have equal signs. Thus, we can precisely determine the relative location of the switched capacitor bank by simply evaluating power factor changes and the signs of voltage and current waveform gradients at the switching instant. The efficacy of our practical direction-finding technique is demonstrated analytically and by way of time-domain simulation models and actual data.