| The development of new energy power generation, distributed energy supply, micro-gridtechnology, helps to make full use of local rich clean and renewable energy sources, toprovide users with a" green power", it is to realize our country" energy-saving emissionreduction" the significant move of the target, and is the current energy shortage andenvironmental pollution problems. Micro-grid as the micro source runs strong uncertainty,with intermittent, complexity, diversity, instability characteristics, the electric energy qualitycharacteristics and traditional power system has the very big difference. Therefore, a networkin the actual operation of the key problem to be solved the problem of electric energy quality.First the formation mechanism of harmonic and interharmonic, voltage fluctuation andflicker in micro-grid was analyzed. Because of the energy generation and supply system inmicro-grid having many power types, control method being complex, operation modechanging characteristics and mostly adopting the interface of electric power electronic, cannot be generated power quality problems of harmonics/interharmonics and voltage fluctuationand flicker. Then the mechanism of harmonic and interharmonic wave and voltage fluctuationand flicker was analyzed. Then several common power quality control device principle andtheir respective advantages and disadvantages are analyzed in detail. Based on the specialpower quality situation in micro-grid, a kind of APF combined with SVG system integratedmanagement method was put forward, the system structure of the model was gave, theworking principles of the system was analyzed, the model of system harmonic domain andfundamental domain was analyzed, and the respective equivalent model and the expressionwas deduced.In the actual situation, a kind of APF and SVC combined system comprehensive powerquality compensator model structure was put forward, the working principles of the systemwas expound, the system harmonic domain and fundamental domain model was analyzed, andtheir own equivalent model and the expression was launched.Determining processing method, several micro-grid models was introduced: CERTSmodel, discrete model and the continuous model. Shortly afterwards the method ofdetermining APF and SVC optimal placement in micro-grid was studied. In a continuousanalytical model and the discrete model of micro-grid, the identification of APF and SVGoptimal mounting point method is described: the optimal placement of APF constraint by thetatal harmonic line loss and the line of the total voltage distortion rate, line loss and minimal total voltage distortion rate lowest point is the optimal mounting points for APF; the optimalplacement of SVG constraint by the total active power loss and total the reactive loss, totalactive power loss and the total reactive power loss minimum point of optimal for SVGmounting points. At the same time the proposed method is validated by the exampleanalysis and simulation test. The example analysis results show that this method was effectiveand feasible.Finally, the APF and SVG joint system cooperative control was studied, presenting amulti objective coordinated optimization control algorithm. The whole control system isdivided into three layers: the execution level, decision-making level and testing level. APFand SVG constitute the executive level; detection processing level controller on initialnetwork parameters are measured in real time, and calculate the APF and SVG compensationsafety restraint; multi-objective controller based on APF and SVG control, responsible forreactive power and harmonic capacity allocation, decision control level. To verify the validityof the multiple optimization coordination control method, simulation and analysis of theexample is researched and the corresponding simulation results was gave. The simulation andexample analysis results show that multiple optimization coordination control method iscorrect, effective and superior. |
