Search

A new high-impedance fault (HIF) detection method using time-frequency analysis for feature extraction is proposed. A pattern classifier is trained whose feature set consists of current waveform energy and normalized joint time–frequency moments. The proposed method shows high efficacy in all of the detection criteria defined in this paper. The method is verified using real-world data, acquired from HIF tests on three different materials (concrete, grass, and tree branch) and under two different conditions (wet and dry). Several nonfault events, which often confuse HIF detection systems, were simulated, such as capacitor switching, transformer inrush current, nonlinear loads, and power-electronics sources. A new set of criteria for fault detection is proposed. Using these criteria, the proposed method is evaluated and its performance is compared with the existing methods. These criteria are accuracy, dependability, security, safety, sensibility, cost, objectivity, completeness, and speed. The proposed method is compared with the existing methods, and it is shown to be more reliable and efficient than its existing counterparts. The effect of choice of the pattern classifier on method efficacy is also investigated. [ABSTRACT FROM AUTHOR]

IEEE Standard 1459 defines the power components based on the fast Fourier series. However, Fourier series assumes the signal is periodic in nature, and provides erroneous assessment of the power components in the presence of transient signals. Therefore, a new method is proposed for the evaluation of the IEEE Standard 1459 power components based on the time-frequency distribution (TFD) and the cross time-frequency distribution (XTFD) of transient signals. The TFD and XTFD preserve simultaneous time and variable frequency information of transient signals, and estimate the instantaneous power components according to IEEE Standard 1459. Results of computer simulated and real-world power quality disturbance case studies justify the effectiveness of the proposed method for the assessment of instantaneous power components under transient conditions. [ABSTRACT FROM AUTHOR]