基于宽频量测间谐波潮流计算的次/超同步振荡溯源方法

宽频量测技术的快速发展为部分新能源发电并网节点的次/超同步振荡监测提供了有效手段，但是由于测量单元布点限制，难以获得全网的振荡传播和分布。为此，提出了一种基于新能源发电并网点宽频量测间谐波潮流计算的次/超同步振荡溯源方法。给出了次同步振荡频率下间谐波潮流算法的网络模型和元件模型，总结了间谐波潮流计算的详细步骤，通过间谐波潮流计算可得到各个节点的间谐波电压电流分布，进而获得全网次/超同步振荡传播路径。当新能源发电系统次同步振荡传播引发邻近火电机组轴系扭振时，存在扭振机组间谐波等效阻抗突变的特性，从而造成间谐波潮流分布发生变化，根据预想振荡状态下间谐波潮流计算结果与实际宽频量测结果间的不同，可用于新能源发电次同步振荡引发邻近火电机组轴系扭振的溯源定位。最后，基于四机两区域系统和IEEE 10机39节点系统算例验证了所提方法的有效性和准确性。

Tracing method of sub-/super-synchronous oscillation based on interharmonic power flow calculation of wide frequency measurement

The rapid development of wide frequency measurement technology provides effective means for monitoring sub-/super-synchronous oscillation of some renewable energy generation grid-connected buses. However, due to the distribution limitation of measurement units, it is difficult to obtain the spread and distribution of oscillation in the whole grid. Thus, a tracing method of sub-/super-synchronous oscillation based on interharmonic power flow calculation of wide frequency measurement for renewable energy generation grid-connected buses is proposed. The network model and component model of interharmonic power flow algorithm under sub-synchronous oscillation frequency are given, and the detailed steps of interharmonic power flow calculation are summarized. The interharmonic power flow calculation is used to obtain the distribution of interharmonic voltage and current at each bus, and then the spread path of sub-/super-synchronous oscillation can be obtained. When the sub-synchronous oscillation propagation of renewable energy power generation system causes the torsional vibration of shaft system in adjacent thermal power units, there is a sudden change in the interharmonic equivalent impedance of torsional vibration units, so that leading to the variation of the interharmonic power flow distribution. According to the difference between the calculative results of interharmonic power flow under the expected oscillation state and the actual wide frequency measurement results, it can be used to trace and locate the torsional vibration of shaft system in adjacent thermal power units caused by sub-synchronous oscillation of renewable energy power generation. Finally, the effectiveness and accuracy of the proposed method are verified by the case study of four-machine two-area system and IEEE 10-machine 39-bus system.