Wind Power Converter Output Power Quality Monitoring Methods

Due to reactive power consumption and randomicity of wind power generation, voltage fluctuation and flicker are arosed by wind turbines during the continuous course and switching operation. The widespread use of variable speed constant frequency technology in wind power system can also produce large amount of high-order harmonic, which exert a bad influence on the electricity network. Therefore, the study of wind power converter output power quality monitoring system has great practical significance in optimizing manual operation and improving the quality of wind energy.Using output wave of the permanent magnet synchronous generator wind power converter as the object, studies of electronic power monitoring technologies based on power quality index systems are presented as follows:1) Build a MATLAB model of permanent magnet synchronous generator wind power converter and verify its correctness. Computing methods of the electrical parameters, harmonic parameters, power parameters and flicker monitoring parameters are proposed based on the output waves of the model.2) A sample-by-two mathematics morphology filter is designed in order to filter the power quality data. Analyzing of the filter effects based on morphology strain wave virify that it can expand the width of conformation frame elements in substance and efficiently filter the high-frequency noise of voltage and current. In addition, detection methods of fault signal based on morphological gradient threshold are studied to implement the real-time detection of voltage and current wave variation trend. Its validlity is verified by simulation result.3) To solve the storing and transmitting problem arosed by large amount power quality data, a data compression method is proposed based on average energy threshold of DCT. It transforms one-dimensional data into two-dimensional data, then does block processing of DCT and rearranges the coefficients. By setting the average energy threshold of block matrix and discarding partial coefficients, data compression can be implemented. The high compression rate is confirmed by experimental simulation.According to the mentioned studies above, a data gathering and processing system with dual-CPU structure based on TMS320F 2812+Atmage64 is desighed to implement power quality monitoring. This system uses the effects and advantages of DSP in analyzing power quality, and the system device work well.