The Research On The Position Of Transient Power Quality

With the development and popularization of high-tech industries such as the computer, power electronic and information technology, power quality transient problems as Voltage sag and discontinuity have already become the focus that numerous fields have paid close attention to. The power quality transient detected and analyzed accurately is as to realize the fault localization, Characteristic extraction, and identification, which is the essential presupposition and basis of monitoring and managing to power quality transient.Because the noise often goes with the electric signal and has big impact to the results, therefore the denoising link is essential. Against the inherent defects of the traditional linear filter in the detection of transient power quality disturbances, this paper uses mathematical morphology morphological filters. On the basis of the research of the morphological operator and traditionally morphology filter, the paper proposes the generalized morphology filter founded on LMS adaptive algorithm. The filter has many benefits, such as small amount of calculation, reservations the details of signal characteristics well. Also it combines the different structural elements.When determining how to choose the coefficients of open-closed and close-opened filter, it no longer uses the simple weighted average as traditional morphology filter, but chooses adaptive algorithm technology basing on minimum mean square error. By amending coefficients gradually, make the filter has better ability. The new morphology filter does better filtering effect from the Matlab simulation results. In the aspect of testing, we use of wavelet algorithm and fractal algorithms to carry out the positioning signal power quality in this paper. And make the contrast analysis of the two .The wavelet transform is a method which is adaptive and localized in both the time domain and frequency domain. According to Mallat algorithm and wavelet transform modulus maxima theory, we take the detection of power quality disturbances signal by the means of multi-resolution decomposition. Generally, different body has different fractal dimension. According to the fractal dimension of the grid fractal dimension, a simple and rapid detection criterion is put forward. Contrast with the wavelet algorithm, the new algorithm has Small amount of computation. Besides, it doesn't have the problem of Zero-crossing detection Failure. Matlab simulation results from the test confirmed the accuracy of positioning algorithm.