基于实测受扰轨迹考虑量测误差的失步解列判据

Out-of-Step Splitting Criterion Based on Real-Time Disturbed Trajectory Considering Measurement Errors

失步解列判据是失步解列控制措施启动的重要依据,要求能够快速、准确地判断出电网的失步状态。针对目前失步解列判据的时效性和准确性不能协调配合等问题,提出一种基于角速度-角半径(v-R)受扰轨迹及其一阶导数随R变化的dv/d R-R受扰轨迹变化趋势的失步解列判据。首先通过降维映射将多机系统实测受扰轨迹映射到一维扩展相平面上,证明了该映射的保稳性。对稳定和失稳受扰轨迹特性进行分析和证明,为克服量测误差产生的误判问题,采用最小二乘法对dv/d R-R受扰轨迹进行实时拟合,通过拟合后曲线判断系统失步情况。在新英格兰10机39节点系统中证明了该判据可以有效地防止误判,另外通过与动态鞍点失步解列判据以及Ucosφ失步解列判据进行对比分析,验证了该判据的快速性。

Out-of-step splitting criterion is an important basis for starting control measures of out-of-step splitting, requiring to judge out-of-step condition rapidly and accurately. However, current splitting criteria cannot take both rapidity and accuracy into account in a coordinated manner. An out-of-step splitting criterion is proposed based on trend of real-time disturbed trajectories, i.e., rotor speed-rotor angle （v-R） trajectory and dv/dR-R trajectory. Dimension reduction for power angle mapping in power-angle space is used to project real-time disturbed trajectory of multi-machine system to one-dimensional extended phase plane, while retaining stability-preserving characteristics. Characteristics of stable and unstable disturbed trajectory is analyzed and proved. In order to overcome misjudgment caused by measurement errors, the least square method is adopted to fit dv/dR-R trajectory. Real-time fitting curve can be taken as judging basis for out-of-step. It is proved that this criterion could effectively prevent misjudgment in New England 39-bus system. Compared with DSP and Ucosφ splitting criteria, rapidity of the criterion is verified.