The Research Of Power Quality Comprehensive Evaluation Method Based On Photovoltaic Power Generation System

With the growing consumption of traditional fossil fuels, the role and prospects of photovoltaic power generation is increasingly widely accepted by the community. However, compared with traditional power generation technology, the photovoltaic power generation technology is strongly influenced by the external environment, power output is intermittent and uncertainty, and it’s power grid through a lot of power electronic device, will bring a lot of power quality problems in power distribution network, affect the stable operation of the power distribution network and user equipment safe use. So how to evaluate the power quality in the photovoltaic power generation system is of great importance.The paper gives power quality comprehensive evaluation of photovoltaic power generation, on the basis of background and significance of photovoltaic system power quality evaluation, and analysis of the current situation of photovoltaic power at home and abroad. So, the main work is as follows:(1) In the discussion of traditional photovoltaic power quality system evaluation methods, the paper improves analytic hierarchy process and fuzzy mathematics method of related shortcomings, proposes a system based on the fuzzy math of analytic hierarchy process to evaluate the power quality problems, in this method, according to the analytic hierarchy process, the power quality indicators of photovoltaic power generation system is layered sequentially, and calculated the relative weight between levels. Then combining the weight and the fuzzy math evaluation method of each index in the membership function, construct combination of membership function judgement matrix, normalize to obtain the value of each index. Finally, it is given comprehensive evaluation value of each index with the method of average weighted, the overall value is the comprehensive evaluation value with respect to its level of power quality, photovoltaic power generation system of power quality evaluation results are obtained.(2) In the paper, the evaluation of transient power quality is based on photovoltaic power station in the low voltage across. In the process of transient power quality evaluation, taking into account all the characteristics of each index corresponds to the amount of its comprehensive effects, draw each index value that constructed fuzzy model, then, application with fuzzy math of analytic hierarchy process to evaluate transient power quality index of photovoltaic power generation system, from the calculated data on the contribution of each evaluation grade, to evaluate the transient power quality indicators.(3) According to the analysis of the test from the actual photovoltaic power generation system, respectively, evaluated the steady-state and transient power quality indicators with the fuzzy math of analytic hierarchy process based on relevant test procedures, calculated the value of power quality for the photovoltaic system, and according with the respective corresponding power quality grade power quality, we will get the impact of the power quality indicators for PV system, finally the value of photovoltaic power generation systems will be obtained.