Abstract: A method of determining peaks in a discrete function. The method comprising the steps of: applying a closing function to the discrete function to generate a closed discrete function; defining peaks within the closed discrete function; sorting the defined peaks according to function value; and applying a threshold value to each sorted defined peak in individual succession, wherein sorted defined peaks having a peak height value above the threshold value are retained within the closed discrete function.

Abstract: A method employed in a condition monitoring unit (CMU) for monitoring a circuit breaker or interrupter to obtain a substantially undistorted version of a waveform suffering from saturation distortion comprises employing a current transformer (CT) to measure a current waveform. The output of the CT is prone to be a partially distorted waveform. The invention is generic in the sense that it does not require parameters associated with the CT characteristics or with the burden impedance on the secondary side of the CT. A digital representation of the partially distorted waveform is obtained, and then undistorted portions of the partially distorted waveform are identified by comparing the amplitude of the partially distorted waveform within a sliding window to a pair of boundary values and identifying as undistorted those portions having an amplitude between the boundary values. Next, distorted portions of the waveform are separated from the undistorted portions, thereby yielding a data record with holes.

Abstract: For the purpose of detecting signals by means of fuzzy-logic classification, these signals are sampled in time and the sampled values are compared with fuzzy threshold values with the aid of fuzzy-logic rules. Strengths which evaluate the similarity of the signal to be detected with the relevant master signal given the application of the relevant rule are determined for each master signal of a signal catalog. Furthermore, a membership is calculated for each master signal as the arithmetic mean of all the strengths, averaged over all the rules, and the signal to be detected is assigned to that master signal whose membership is a maximum.