Study On Grid Connected Distributed Photovoltaic Effect On Distribution Network Voltage

With the massive consumption of the traditional fossil energy, the primary energy consumption brings serious environmental pollution and the resources are exhausted. In the past ten years, green environmental protection of renewable energy utilization has been rapidly developed. Photovoltaic power generation technology application has been strongly supported by the state, has become one of the main ways of renewable energy utilization. Distributed photovoltaic has its unique advantages are being vigorously supported by the state. Taking Jiangsu province as an example, distributed PV in just a few years has never developed into one million kilowatts of capacity, and the trend is accelerating. Distributed photovoltaic application completely changed the structure of the distribution network, in the green environmental protection power generation at the same time also has a certain impact on the distribution network. To develop large scale distributed PV access distribution network is of great theoretical and practical significance for solving these problems.There is much influence of distributed PV on the operation of the distribution network, among which the influence of the voltage of the distribution network is one of the most important factors. Distributed PV as a power distribution network to change the original distribution network voltage distribution, to varying degrees to reduce the supply side of the system to provide the current, improve the voltage distribution network node. With the gradual increase of grid connected photovoltaic power generation system, the reverse power flow and the grid voltage can often appear in the distribution network. At the same time, due to the fluctuation of the photovoltaic power generation, the voltage fluctuation of the distribution network is increased.Solving reactive power and voltage problems in distribution network involves many aspects of research. The power flow calculation of distribution network is an important premise to study the influence of distributed PV on the voltage of distribution network, by analyzing the current status of power flow algorithm and the characteristics of distributed PV, using the forward and backward iteration method of power flow calculation of distribution network 10kV. Using Matlab/ Simulink software static analysis of different distributed PV capacity, access to distribution network node with different examples, and calculate different voltage changes and distributed dynamic photovoltaic power changes caused by the dynamic change of the distribution network voltage. The voltage variation and voltage deviation caused by large scale distributed PV system are analyzed from two aspects of voltage magnitude and fluctuation.In solving voltage problems, from the structure of the distribution network, the main factors affecting the voltage and the solution to the problem of distribution network voltage, a comprehensive analysis of the photovoltaic inverter independent voltage, on load voltage regulating transformer pressure, adjusting distribution network wiring structure, using a dynamic reactive power compensation device of non adjustable voltage and increase the energy storage device, etc. the distribution network voltage control scheme. The three methods of automatic voltage regulation, the photovoltaic inverter independent voltage control, on load voltage regulating transformer voltage control and adjusting distribution network wiring structure are selected, and the further analysis and simulation calculation are carried out. The advantages and limitations of the three methods are summarized. Based on the existing control technology, the principle of the control strategy of distribution network voltage is proposed.