适用于交直流混联受端电网的机组组合模型及算法

特高压直流双极闭锁后,受端电网可能出现频率降低、功率大范围转移等运行情况,甚至引起低频减载、线路越限等电网事故。针对上述问题,提出一种用于交直流混联受端电网的机组组合模型,考虑了直流闭锁后的一次调频容量约束和二次调频后节点电压、线路功率等电网运行约束条件,保证直流闭锁后电网频率和潮流仍可运行在合理范围内。根据模型特点,采用基于Benders分解的混合整数规划算法进行求解,得到直流最优输送容量、最优机组启停和出力计划,在充分消纳直流输送功率的同时提高了交直流受端电网运行的安全性。最后,通过改进后的10机39节点和江苏电网两个典型的交直流混联电网算例进行仿真计算,结果验证了所述模型和算法的正确性和有效性。

Unit Commitment Model and Algorithm for Receiving-end Power Grid in Hybrid AC/DC System

After high voltage direct current(HVDC)is blocked, frequency deviation and power translation will emerge in the receiving-end of hybrid AC/DC system. Such accidents as under-frequency load shedding and branch violation would become more serious. For the purpose of solving the above problems, a unit commitment model is proposed for receiving-end power grid in the hybrid AC/DC system, including capacity constraints on primary frequency regulation and bus voltage/branch power constraints when secondary frequency regulation finishes. As a result, frequency and power flow would be ensured while HVDC blocked failure happens. According to the characteristics of the model, Benders decomposition and mixed integer programming algorithms are used to get the optimal transmission power of HVDC and planning of normal units. HVDC power will be completely accommodated while AC/DC system safety will be ensured. In the end, two typical cases of 10-machine 39-node system and Jiangsu power grid are employed to test the correctness and effectiveness of the model.