计及换流器损耗的风电经柔直并网系统的随机最优潮流模型

Stochastic Optimal Power Flow of Wind Turbine through Flexible Grid Connected System Considering Converter Loss

由于风电的随机性和不确定性,使得风电大规模并网后电力系统的安全稳定运行难度增大,因此有必要对风电经柔直并网系统的随机最优潮流展开深入研究。提出一种计及换流器损耗和风电随机性的风电经柔性直流并网的随机最优潮流模型。首先,建立风电功率数学模型和计及换流器损耗的VSC-HVDC数学模型,考虑风电并网时换流站的不同控制方式;其次,利用场景法模拟风电功率的不确定性,并通过Kantorovich距离的场景削减技术提高计算效率,构建风电经柔性直流并网系统随机最优潮流模型,采用内点法对优化模型进行求解,利用统计学方法计算目标函数的数字特征;最后,以修改的WECC 2机5节点系统和IEEE-118节点系统为例进行仿真分析,验证所提出优化模型的合理性和有效性。

Because of the randomness and volatility of wind power,large-scale grid-connection will bring great challenges to the safe and stable operation of power systems.Therefore,it is necessary to deeply study the stochastic optimal power flow of wind power through(VSC-HVDC)grid-connection system.In this paper,a stochastic optimal power flow model for wind power through flexible DC grid-connected system is presented,which takes into account converter loss and wind power randomness.Firstly,the mathematical model of wind power and the VSC-HVDC mathematical model considering converter loss are established,and different control methods of the converter stations are analyzed when wind power is grid-connected.Secondly,scenario method is used to simulate the uncertainty of wind power,and Kantorovich distance based scenario cutting technology is used to improve the calculation efficiency.Thirdly,the stochastic optimal power flow model of wind power through the flexible DC grid-connected system is constructed,and the model is solved by the interior point method,and the numerical characteristics of output variables are obtained by using the statistical method.Finally,taking the modified WECC 2 machine 5 node and IEEE-118 node system as examples,the calculation example is analyzed to verify the rationality and validity of the proposed optimal model.