基于WARD等值的电网限流运行方式优化方法

控制短路电流水平，保证断路器安全是电网运行方式安排的重要任务。线路开断及母线分裂以增大变电站母线与电源之间的电气距离是限制电网短路电流水平的有效措施，但同时也可能引起电网运行可靠性水平的降低。首先根据对网络拓扑结构的分析及线路开断前后超标站点的短路电流变化确定可开断支路集；然后添加功率平衡方程约束、支路潮流约束以及N-1安全约束；以开断线路数最少为目标，提出了控制短路电流水平的电网运行方式优化模型，并借助WARD等值缩小模型规模，提高了模型的求解效率。所提模型为混合整数线性规划模型，可以采用线性规划单纯形法及分支定界法迅速求解。使用C++编写了仿真程序，通过对IEEE39节点系统和某实际电网的仿真分析验证了所提模型的正确性和算法的有效性。

A grid operation mode optimization method for controlling short-circuit current level based on WARD equivalence

An important targetof operation mode planning for power grid is tocontrol short-circuit current level so as to guarantee the security of the circuit breaker. Effective measures like circuit opening and bus splitting will enlarge the electrical distance between buses in substations and power plants, in spite of reducing operation reliability of power grid. This paper proposes an optimization model of operation mode planning for power grid. The objective is to minimize the numbers and breaking capacity of opened circuits. The constraints are short-circuit current limits calculated by node-voltage method, network connectivity limits formulated by DC power flow equations, branch power flow constraints and N-1 security constraints. Taking the least number of breaking circuits as target, a power grid operation mode optimization model to control the short-circuit current level is proposed. WARD equivalence is used to narrow the size of the model and improve the calculation efficiency of the optimization model. The model describes a mixed integer linear programming problem, therefore can be solved by linear programming simplex method and branch and bound method. Simulation program written in C++ is applied to instances of IEEE 39-bus system and an actual power grid. The optimized results confirm the correctness of the proposed model and validity of the algorithm.