基于定常海森矩阵的配电网三相最优潮流模型

含有高比例分布式电源和多种离散可调设备的主动配电网最优潮流问题,实质上是一种非凸、非线性混合整数优化问题,这类问题的求解速度较慢。文中提出了基于定常海森矩阵的配电网三相最优潮流模型,模型中考虑了三相变压器、具有三相耦合特性的分布式电源、分相调压器等设备的二次模型,以保证海森矩阵为常数。通过增加支路电流为待求变量,提出直角坐标系下三相变压器的二次模型,使优化模型的海森矩阵为常数阵,从而降低最优潮流的计算时间。构建了计及分布式电源三相功率耦合特征的配电网三相最优潮流模型,比较了二次罚函数和高斯罚函数对离散控制变量的处理效果,并应用预估—校正原对偶内点法对优化模型进行求解。同时,提出加入调压器的二级迭代最优潮流策略,从而进一步优化目标值。最后,通过算例验证了所建模型与所提方法的正确性与有效性。

Three-phase Optimal Power Flow Model for Distribution Network Based on Constant Hessian Matrix

The optimal power flow problem of the active distribution network with distributed generators and various discrete adjustable devices is essentially a non-convex, nonlinear mixed integer optimization problem. The solving speed of this kind of problem is slower. This paper proposes a three-phase optimal power flow model for distribution network based on the constant Hessian matrix. In the model, the second-order model of the three-phase transformer, the distributed generator with three-phase coupling characteristics and the voltage regulator are considered, which guarantee a constant Hessian matrix throughout iterations. By adding the branch current into the demand variables, the second-order model of three-phase transformer under Cartesian coordinate system is proposed, which makes the Hessian matrix of the optimization model become a constant matrix, thus reducing the computing time of optimal power flow. The three-phase optimal power flow model for active distribution network with three-phase power coupling characteristics of distributed generators is developed. The effects of the quadratic penalty function and Gaussian penalty function on the discrete control variables are compared, and the optimization model is solved by the prediction-correction primal-dual interior point method. Meanwhile, the two-stage iterative optimal power flow strategy with the voltage regulator is proposed to further optimize the target value. The correctness and effectiveness of the proposed model and method are verified by an example.