Abstract: A method and apparatus for detection of a failure of a rectifier connected to a passive harmonic filter with a tuned circuit reactor, or of the filter itself, and for generating system currents in the filter, using low cost voltage sensing, modeling of reactor resistance and saturable inductance, and a mathematical integration. The harmonic spectrum of the rectifier current is used to determine an estimate of the rectifier impedance. A template of expected rectifier current is calculated, and compared against a rectifier current calculated on the basis of sensed voltages, to generate a difference signal. The difference signal is compared against a predetermined fault threshold to determine if an error has occurred. The apparatus includes a DSP obtaining the voltages of the source and load, and the tuned circuit reactor voltage, calculating the template, and comparing the actual voltages with the template, to annunciate a fault.

Abstract: A method and apparatus for detection of a failure of a rectifier connected to a passive harmonic filter with a tuned circuit reactor, or of the filter itself, using low cost voltage sensing, modeling of reactor resistance and saturable inductance, and a mathematical integration. The harmonic spectrum of the rectifier current is used to determine an estimate of the rectifier impedance. A template of expected rectifier current is calculated, and compared against a rectifier current calculated on the basis of sensed voltages, to generate a difference signal. The difference signal is compared against a predetermined fault threshold to determine if an error has occurred. The apparatus includes a DSP obtaining the voltages of the source and load, and the tuned circuit reactor voltage, and configured to compare the currents calculated from the actual voltages with the currents in the template, and to thereby determine whether to annunciate a fault.

Abstract: A method and apparatus for detection of a failure of a rectifier connected to a passive harmonic filter with a tuned circuit reactor, or of the filter itself, using low cost voltage sensing, modeling of reactor resistance and saturable inductance, and a mathematical integration. The harmonic spectrum of the rectifier current is used to determine an estimate of the rectifier impedance. A template of expected rectifier current is calculated, and compared against a rectifier current calculated on the basis of sensed voltages, to generate a difference signal. The difference signal is compared against a predetermined fault threshold to determine if an error has occurred. The apparatus includes a DSP obtaining the voltages of the source and load, and the tuned circuit reactor voltage, and configured to compare the currents calculated from the actual voltages with the currents in the template, and to thereby determine whether to annunciate a fault.