基于支路潮流线性化方程的有序充电快速求解方法

针对传统有序充电方法计算效率低、未计及配电网三相不平衡与节点电压和支路电流约束的不足,推导了三相平衡与不平衡配电网的支路潮流方程,提出了将方程非线性项线性化的方法。构建了以车主充电总费用最小为目标函数,节点电压、支路功率、充电功率为不等式约束,支路潮流方程、充电需求为等式约束的电动汽车有序充电的模型。提出了采用二阶段线性规划进行求解的方法。第1阶段线性规划采用忽略支路潮流方程非线性项的简化线性模型求取估算的支路优化有功功率、无功功率、节点电压,作为支路潮流方程非线性项线性化的初始点。第2阶段线性规划采用近似线性模型计算最优充电功率。采用3个仿真算例与其他方法进行了对比,验证了所提出方法的性能。

Fast Solving Method of Ordered Charging Based on Linearized Equations of Branch Flow

In order to elimate the disadvantages of low calculation efficiency of traditional ordered charging method and not taking the three-phase imbalance of distribution network, constraints of node voltage and branch power flow into account, the branch power flow equations of three-phase balanced and unbalanced distribution networks are derived. The linearization methods for the nonlinear terms of equations are proposed. The ordered charging model of electric vehicles is developed, which takes minimum charging cost of owners as objective function, takes node voltage, branch power and charging power as the inequality constraints, and takes branch power flow equations and charging demand as equality constraints. The solving method is proposed by using two-stage linear programming. The linear programming of the first stage calculates the estimated optimized active power, reactive power and node voltage of the branch as linearized initial points of nonlinear terms for branch power flow equations by using simplified linear model, which ignores the nonlinear terms of branch power flow equations. The linear programming of the second stage calculates the optimal charging power by using the linearized branch power flow equations. The capabilities of the proposed method are verified by using three simulation cases compared with the selected methods.