基于感应电动机网荷互馈特性的暂态电压失稳机理探析

Mechanism Analysis for Transient Voltage Instability Based on Crossfeed Characteristics Between Power Network and Load of Induction Motor

正确认识电压失稳机理是进一步对电力系统电压稳定问题进行深入研究的关键。分析了网络视在功率传输特性和感应电动机负荷特性,揭示了以感应电动机为核心的暂态电压失稳正反馈动态过程。将与滑差相关的感应电动机负荷及网络视在功率传输的相互作用关系定义为感应电动机网荷互馈特性,并据此进一步分析了含有感应电动机负荷的系统电压崩溃过程,明确了基于感应电动机网荷互馈特性的暂态电压失稳机理,提出了感应电动机负荷电压失稳判据,构建了简单系统算例验证分析结果。分析表明,以感应电动机为核心的电压失稳正反馈动态过程是系统暂态电压失稳的重要环节;将感应电动机故障切除时滑差对应的恢复电压作为判断感应电动机电压稳定的必要条件,能够提高暂态电压失稳判定的准确性与适用性。所述电压稳定判据为预防电压失稳现象的发生和制定电压失稳解决措施提供了有力的理论支撑。

To correctly reveal how voltage instability works is the key to in-depth study of power system voltage stability.The characteristics of network apparent power transmission and induction motor load are analyzed,and the transient voltage instability positive feedback dynamic process centering on the induction motor is discussed.The relationship between the induction motor load and apparent power transmission of network is defined as crossfeed characteristics between power network and the load of induction motor.Accordingly,the process of voltage collapse with the induction motor load is further accounted for.In addition,the transient voltage instability process based on the crossfeed characteristics is further clarified,and an induction motor load voltage instability criterion is proposed.A simple system model is built to verify the result.The analysis shows that the positive feedback dynamic process centering on the induction motor is an important step for the system transient voltage instability.When clearing the fault with the induction motor,the slip＇s corresponding restored voltage is used as a necessary condition for induction motor voltage stability judgment,improving the accuracy and applicability.A powerful theoretical support is offered by the proposed voltage stability criterion to prevent voltage instability and put forward related countermeasures.