Voltage Control For High Penetration Of PV On Distribution Systems And Simulation System Design

Under the situation of environmental pollution and energy crisis havebecome the concern of all countries in the world, the new energy industryobtains the fast development. In the electric power industry, distributedgeneration based on new energy has been the focus of current research. Thedevelopment of distributed power supply brings ample technological andenvironmental benefits to the traditional distribution networks under thederegulated market structure. Solar energy is the world’s major renewableenergy source and is available everywhere in different quantities. Solarphotovoltaic generation is one of the fastest growing DG technologies, with a lotof countries in expressing interest in its implementation. It will bring certaininfluence to distribution system for grid-connected PV on distribution network,including system structure changes and power flow changes. With the increaseof photovoltaic permeability, feeder voltage will increase or even adverse thevoltage limit. So it will affect the normal operation of distribution network. Inorder to meet the demand of electric power development under the new situation,this paper analysis the voltage regulator and capacitor coordination control strategy and smart inverter volt/var control strategy based on the voltage effectof different photovoltaic permeability. These strategies will improve the voltageand restrain the excess of voltage limit. The detailed researches are as follows:(1) OpenDSS is an open source distributed power simulation tool. At firstwe have a understand of the simulation software and introduce the structure andinput and output file of OpenDSS software. And then the modeling ofdistribution network system is discussed and the modeling of powertransmission components and power conversion elements are descriptrespectively. Then the fast power flow calculation method is introduced and thecalculation steps are given in detail. Finally we introduce the analysis method ofdistribution network based on fast power flow calculation method, includingtime series trend analysis and probabilistic load flow analysis.(2) The distribution network testing system is modeled on the OpenDSSplatform. The photovoltaic element parameters are set and the load operationcurve and light output curve are constructed. Through time series power flowcalculation for test system and analysis of the impact of different PVpermeability on feeder voltage, we can draw the voltage rise which may excessthe limit and the feeder terminal voltage drop which may below the standardrange. For the two problems, we put forward voltage regulator and capacitorcoordination control scheme based on the understanding of its control principle.At last, the control scheme is simulated.(3) The intelligent inverter volt/var control method is analyzed from theoutput control characteristic of photovoltaic power generation component. First of all, we give the principle of intelligent inverter volt/var control method. Thenwe analyze the implementation process and the control iteration process inOpenDSS platform. After constructing distribution network feeder system andseting the volt/var control curve, we do inverter volt/var control simulationanalysis respectively in the general iteration mode and time series calculationmode. Finally according to the analysis results, we give the voltage for differentPV permeability.(4) Because the realization of distribution system voltage control method isinflexibility for OpenDSS characteristics, so we develop the simulation systembased on OpenDSS COM. Firstly we introduce the environment and technologyfor system design. Then we develop the system login module, parameters settingmodule, program interface module, Excel import module, data display module,drawing function module separately. The calculation example shows that thedesign with great interaction and flexibility.