基于直流潮流和虚拟母线的多控制节点防连锁过载跳闸策略

A Multi Control-node Emergency Control Strategy Based on DC Power Flow and Virtual Bus

为消除因潮流转移导致的线路连锁过载,提出一种基于直流潮流和虚拟母线的多控制节点防连锁过载跳闸策略。利用直流潮流模型中的GSDF和GGDF计算平衡机的灵敏度,将平衡机参与到紧急控制中,并根据GSDF和GGDF的应用特点,对不同类型的控制节点组选择不同的灵敏度参数。利用图论将电网拓扑图划分为多个广义潮流转移区域,证明区域外节点和区域连接割点对区域内线路有相同的GSDF,将区域外节点与其相应的区域连接割点等效为虚拟母线,使计算范围从全网简化到过载线路所属的广义潮流转移区域。当利用综合灵敏度选择的控制节点组会使部分过载线路过载程度加重时,采用多控制节点法可有效避免过载线路功率增加。利用反向等量调整法和往返功率预测法,并考虑正常线路冗余量约束计算功率调整量,有效避免了潮流校验,提高了紧急控制速度。在IEEE39节点系统中对该方法的可靠性和优越性进行了验证。

To eliminate the cascading overload caused by power flow transferring, a multi control-node emergency control strategy based on DC power flow and virtual bus is put forward. The sensitivity of the balancing machineis firstly calculated by GSDF and GGDF in the DC power flow model. Then the balancing machine participates in the emergency control. According to the characteristics of GSDF and GGDF, different types of control-node sets utilize different sensitivity parameters. The network topology of the power system is divided into generalized power flow transferring zones by graph theory. The nodes outside of the zone and the zone connection cut point are proved to have the same GSDF with the lines inside of the zone. Then the outside nodes and the zone connection cut point are the equivalent to the virtual bus, which simplifies the computational area from the total network to the generalized power flow transferring zone with the overload lines. When the control-node set selected by comprehensive sensitivity exacerbates the overload degree of few overload lines, the multi control-nodes can effectively avoid the situation. Considering the redundant power of normal lines, the reverse equivalence adjustment method and the round-trip power prediction method are utilized to determine the adjustment power, which avoids the power flow verification and improve the emergency control speed. The validity and superiority of the method are verified in the IEEE39 bus system.