Research On Reactive Voltage Assessment Technology For Distributed Photovoltaic

In recent years,with the increasing scale of distributed photovoltaic which connected to distribution power systems,the problems of uncertainties in power systems have become significant,due to the randomness and intermittency of distributed photovoltaic.Therefore,carrying out reasonable and accurate assessments of reactive power technology research,is helpful for guiding the corresponding control measures,improving power quality and the security of the power grid operation stability,but also through reactive power compensation,energy conservation and loss reduction,and operational efficiency can all be achieved.For solving distributed photovoltaic reactive voltage assessment problem,this paper carried out the basic theory of distributed photovoltaic modeling research.Then,on this basis,evaluation index system of reactive power operation is built,and their respective combination weights are analyzed.At the same time,the corresponding evaluation method is studied.The analysis of the simulation and actual engineering case,shows that the proposed method is effectiveness and universality.The main contents of this paper are as follows.(1)Firstly,the basic principle and mathematical model of typical distributed power supply is researched.At the same time,the incremental conductance method is used to control the duty ratio Boost circuit to maximum power point tracking(MPPT)control,and uses the constant power control(PQ control photovoltaic)to achieve inverter control.These can provide a good basis of the analysis for follow-up assessment technology research.(2)Based on voltage and reactive power factors,the evaluation index system of distributed photovoltaic reactive voltage can be established,and then,analyzes the characteristics of each index,and on the basis of establishing the relevant evaluation index grade range and the limit value are analysed,in order to facilitate subsequent quantitative analysis of the evaluation object.(3)By using analytic hierarchy process(AHP)and the variation coefficient method,to determine the subjective and objective weights,respectively.Through the analysis of the performance comprehensive weights,so as to avoid a single way of empowerment may lead to biased.Research on assessment of the commonly used quantitative research method,and through the comparison research on the advantages and disadvantages of the various evaluation methods,the two kinds of grey theory and distance algorithm are selected,to analyze the basic theory and assessment steps,and study the similarity matching algorithm specific methods and implementation process.(4)Research on modeling of distributed photovoltaic system,through the simulation analysis data waveform,such as I-V、P-V characteristics,the simulation model and the corresponding control strategy is shown as be effective.Then,based on the simulation analysis data,comprehensive evaluation and layered evaluation can be carried for four different types of scenes.Finally,solar photovoltaic power station actual engineering case and the corresponding analysis shows that the effectiveness of the proposed evaluation index system and evaluation to actual application.