Reactive Power Optimization Of The Distribution Network With Distributed Generation

With the global environmental issues and energy supply issues become increasingly prominent, distributed generation technology has been developing rapidly, distribution network with distributed power injected as a useful supplement for large grid has become a common understanding. However, after the distributed power injected to distribution network, the power flow, network power losses and node voltage will be changed, the original reactive power compensation changed too. Therefore, in order to keep the distribution network keep the economy running, the distributed generation in distribution network need be controlled appropriately. The original reactive power compensation device also should be reconsidered.Firstly, this paper describes the background and significance of the subject, then the overseas and domestic research status of distribution network optimization technologies and distribution network optimization problem with distributed generation are summarized, and then the power flow calculation model of distributed generations in distribution network is summarized, and then analyzes the impact of distributed power losses and voltage, the methods of reactive power compensation with distributed generation injected are expatiated. Under the constraint of satisfying the operation constraints of the distribution network and the action times of the compensator, take the load and distributed power randomness into account, the greatest benefit for the overall goal in a day of distribution network is proposed, the objective function include the investment of distributed generation, maintenance costs of reactive power compensation devices and its maintain costs. Using power loss rate to control the compensator action or not when the time load change. In order to improve the calculation speed, elitist strategy is used to improve generation algorithm when solve the optimization model in this paper. Study results show the proposed method is effective solution to reduce network losses, realize dynamic reactive power distribution network optimization.Different type loads have different voltage characteristics, especially in the case of large voltage deviation. Taking load voltage characteristics into account can be close to a more accurate power flow calculation result. It is helpful for reactive power optimization. In addition, when the distributed photovoltaic power generation is connected with the power grid, it can also provide a certain reactive power when the output power is active. Then the reactive power optimization model of distribution network considering the static characteristics of load voltage and the reactive power output of the distributed PV system is proposed. The simulation results show that the optimization model can reduce the operation cost of distribution network, and it has a certain application reference value.In order to explore the correlation between distributed power output and load demand on the distribution network reactive power optimization effect, coefficient of correlation is used to describe matching degree between distributed power output and load demand, the distribution network is divided into different types of load, under different distribution generations penetration the simulation tests are proposed. The simulation results show that the greater the correlation coefficient between the output and the load demand, the less the compensation cost and power loss, which is more advantageous to the economic operation of the distribution network.