基于广域实测受扰轨迹的失步解列判据

A Criterion for Out-of-step Islanding Control Based on Wide-area Disturbed Trajectory Measurements

对于复杂大区电网将相对角大于某个固定值作为失稳的标准是相当危险的,而传统失步解列判据通常以功角摆开360°作为失步的标准。文中提出利用相量测量单元(PMU)实测机组受扰轨迹,通过互补群惯量中心—相对运动保稳变换得到映像单机系统P(δ)轨迹,如果该轨迹上出现动态鞍点(DSP),则判断系统失步,触发命令将系统在振荡中心处解列。该方法严格符合扩展等面积法则(EEAC)量化分析技术的稳定机理,且仿真结果表明,在某些场景下能比传统失步解列判据提前判断出系统失步。

Conventional out-of-step islanding device generally takes relative power angles achieving 360° as the indication of out- of-step condition although the risk of such judgment relied solely on a fixed threshold of angle difference in complex power systems has been pointed out. A new method for islanding control of complex power systems is proposed. The system is separated at the oscillation center upon identification of a dynamic saddle point （DSP） on the time-varying OMIB equivalent trajectory transformed from real-time measurements of wide-area power angle trajectories by using the complementary-cluster center-of-inertial （CCCOI） transformation. The proposed method strictly conforms to the instability detection mechanism of extended equal-area criterion （EEAC） quantitative analysis theory, and the effectiveness of the method is demonstrated by simulation results. In some cases, the new method is able to detect the out-of-step condition earlier than the conventional out- of- step islanding criterion.