Reactive Power Optimization Of Transmission Network With Wind-Power

As a clean and renewable energy resource, wind-power has already been one of the fastest growing distributed power systems. And it has drawn more and more attentions of domestic and international researchers recently. Grid-connected of wind-power can improve the supply reliability by meeting the reserve demand of the main network. However, the outputs of wind-power would fluctuate with the geography position and the climatic conditions, which will greatly affect the voltage stability and reactive power distribution of network. Especially, with a large energy penetration of wind-power, grid integration may change the unidirectional transfer of energy. To schedule reactive power distribution reasonably for secure and economy of network, the reactive power optimization of the transmission network with micro-grids is studied.Grid integration model of wind-pwer is presented on PSCAD platform. With the maximum utilization, integration effects of wind-power to the distribution network are analyzed with variable energy penetration ratios. The simulations have been done basing on a simplified model of the distribution network. And he results show that wind-power can relieve low power of main network in a certain degree. However, with a high energy penetration ratio, the energy would change with the fluctuant voltage of wind-power, which has great influence on the reactive power of the main network.With the divided-period decoupling strategy, the forecasting load curve of next day and the prediction output curve of distribution network are segmented. So that the dynamic reactive power optimization is converted into static reactive power optimization of multiple time periods. Then, the constriction factor particle swarm optimization algorithm and the human group optimization algorithm are used for the dynamic reactive power optimization of the transmission network.The results show that the network losses would be least when the distribution network with wind-power can be compensated locally. The distribution network for grid-connected suits to approach the reactive power compensation device or generator set in the position planning of grid-connected wind-power. Moreover, with the fixed selecting locations and capacities of compensations, the network losses would increase inevitably with more distribution networks accessing wind-power. It is necessary to optimize reactive power planning of the transmission network with multiple wind-powers reasonably for enhancing the operation enconomy of network.