基于广域保护系统的距离后备保护整定方案

发布时间：2019-05-10 19:15

【摘要】：电网中发生潮流转移现象后,受影响的输电线路会承受大量的转移负荷,进入过负荷运行状态。距离保护后备段的整定要求躲开线路正常运行时的最小负荷阻抗,因此潮流转移带来的线路过负荷将会对距离保护后备段带来显著影响。针对这一情况,提出了一种能够应对潮流转移情况的距离后备保护整定方案。该方案基于广域保护系统,利用WAMS可测幅值与相角的特点快速计算线路的视在阻抗值。然后根据线路视在阻抗的变化幅度确定线路所承受的转移负荷比例,针对线路不同的过负荷状态进行与之对应的后备保护整定值调整,既防止过负荷线路上的后备保护发生误动,又使后备保护保有正确识别短路故障的能力。最后将整定信息与负荷波动情况上传至调度中心,为调度中心进行负荷控制提供辅助决策,并依据调度中心的决策进一步调整后备保护的整定值,直至线路恢复正常的负荷输送状态。以新英格兰10机39节点系统为样例,采用BPA仿真验证了该方案的有效性。
[Abstract]:After the power flow transfer occurs in the power grid, the affected transmission lines will bear a large number of transfer loads and enter the overloading operation state. The setting of distance protection backup section requires avoiding the minimum load impedance when the line is in normal operation, so the line overload caused by power flow transfer will have a significant impact on the distance protection backup section. In view of this situation, a distance backup protection setting scheme which can deal with power flow transfer is proposed. Based on the wide-area protection system, the apparent impedance value of the line is calculated rapidly by using the characteristic of the measurable amplitude and phase angle of WAMS. Then, according to the change amplitude of the apparent impedance of the line, the proportion of the transfer load borne by the line is determined, and the corresponding backup protection setting value is adjusted according to the different overload state of the line. It not only prevents the back-up protection on the overloaded line from maloperation, but also makes the backup protection retain the ability to correctly identify the short-circuit fault. Finally, the setting information and load fluctuation are uploaded to the dispatching center, which provides an auxiliary decision for the dispatching center to carry out load control, and further adjusts the set value of the backup protection according to the decision of the dispatching center. Until the line returns to the normal load transmission state. Taking the New England 10-machine 39-node system as an example, the effectiveness of the scheme is verified by BPA simulation.
【作者单位】：国网北京经济技术研究院;
【分类号】：TM773

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