Research On Interactive Behavior Between Distributed Pv Generation System And Distribution Line With High Penetration

With traditional fossil energy consumption and widespread concern on environmental issues, more attentions are paid on solar energy and other clean energy. Distributed PV generation systems develop rapidly. Whereas solar radiation is not stable with intermittent and fluctuation. Large-scale of distributed power injection may affect the stability of the distribution network system.Firstly, a traditional distributed PV systems based on current-controlled inverter is built to explore the impact of distributed PV power with high penetration injection into distribution network in chain. Distributed generation systems power factor output is unity. However, different injection points, different line impedance R/X ratios and different distributed loads will affect distribution line voltage in different levels.Secondly, three basic grid-tied control modes: synchronous generator control mode, maximum power control mode and voltage control mode, are proposed based on the voltage-controlled inverter control strategy. These three models are proven to improve control ability of grid-tied inverter.Thirdly, analysis and evaluation of the current distortion for photovoltaic system with isolation transformer are conducted to explore the effect on power quality with high penetration PV power injection into distribution network. The model of voltage controlled inverter connecting with grid is built and the output characteristic is controlled in different power factors. Analysis and evaluation of the impact of the distribution network voltage and power loss distributed power grid are conducted based on that output characteristic. And then, several typical power control methods are discussed by contrasts.Finally, two grid-tied control modes with reactive power regulator are proposed based on the evaluation results. Simulation and experimental results verify that distributed PV generation system working in these grid-tied control modes can optimize the distribution network operation states with high penetration.In this paper, five grid-tied control modes are proposed for distributed generation system by exploring the interaction mechanism between distributed generation systems and distribution network. These five grid-tied modes are proposed based on voltage controlled inverter with axes, which improve the distribution network ability to accept new energy and improve network-source interactive capabilities under high penetration conditions. In this paper, the achievement can provide theoretical reference and practice application significance for distributed power generation system injection into distribution network.