Power Quality Research of Photovoltaic Power System in Substation
|School||Shanghai Jiaotong University|
|Keywords||photovoltaic power generation system power quality photovoltaic inverter Matlab simulation analytical hierarchy process weighted TOPSIS comprehensive evaluation distribution network|
The energy situation today is getting more and more serious. The role and application prospect of PV power system has been generally accepted by society. So carrying out photovoltaic power system into application and popularization is significant. Because characteristics of the PV power system are different from those of the conventional power generations, it is necessary to make an overall research for the grid-connected photovoltaic power system to make maximum use of solar resources.The PV power generation systems in Fengzhou substation and Mengzi substation were researched to master the system components parameters, system location and orientation settings. On the basis of the statistical data of the PV power system in Fengzhou substation, the effects of the temperature, illumination intensity and time on the efficiency of the PV power system have been researched.By studying the structure, the operating characteristics and control strategies of the PV power system, this paper analyzes the power quality influence factors of each partof the PV power system, and puts forward the corresponding improvement measures to improve the power quality. The inverter control strategy has been improved to make it achieve the triple multiplexing function which containing maximum active power output, harmonic suppression and reactive power compensation. It can improve the grid’s power quality at the source. The PV power system simulation models have been built using Matlab/simulink. Through the simulation, power quality problems of the PV power system and the effect of various improvement measures have been analyzed.A method based on improved analytical hierarchy process and weighted TOPSIS to evaluate the power quality is presented. The consistency of the judgment matrix could be significantly improved by analyzing the relationship between the comparison matrix and the judgment matrix’s inconsistency. Therefore the index weights are more reasonable. The inverted sequence of the weighted TOPSIS is solved by considering the specified values of the national standards of power quality as the ideal solution and the limit values as the negative ideal solution. This method can judge whether the results are qualified and qualitative grade them. One of the development trends of the PV power systems is used in the micro-grid. So considering the specific conditions of the distribution network planning stage containing micro-grid, another method is presented. By using the iproved AHP combined with the different types of distributed generators and their capacity in the micro-grid and the short-circuit capacity of each micro-grid’s grid-connected point, the indexes are comprehensive quantified and the comprehensive evaluation value of power quality could be obtained. Those two methods are applied respectively to the PV generation systems in the Mengzi and Fengzhou substation and the distribution network planning schemes.