一种综合判别电力系统失步的新方法

A New Method of Synthetic Judging Out-of-step on Power System

本文通过对电力系统异步运行状态特征的研究,提出一种失步保护综合判别新方法。该方法由三部分元件组成,分别为失步起动诊断元件、失步区域判断元件和失步跳闸时机选择元件。失步起动诊断元件利用系统两侧的功角差和功角滑差判断电力系统是否开始发生失步,并以正序电压和正序电流作为辅助判断条件以增加可靠性。失步区域判断元件利用区域继电器原理判断失步解列的区域。失步跳闸时机选择元件通过Ucos原理统计失步次数,并利用功角差作为辅助判据来选择最佳跳闸时机。当3个元件同时动作时,失步保护动作将系统解列。该方法准确可靠且不受系统运行方式影响。通过RTDS仿真实验,验证了该方法的可靠性。

Based on the study of the characteristics of the asynchronous operating power system, this paper provides a new method of out-of-step protection. This new method consists of three components： out-of-step element diagnostic detection, out- of-step region judgment element and out-of-step trip timing selection element. The first element（ out of step diagnostic element） uses differential angle and slip angle between two ends to determine whether power system begins to oscillate. To increase the reliability, the positive sequence voltage and current are used as an auxiliary condition. The second element uses the principle of regional distance relay to judge the oscillation area. The third element uses Ucos principle to count the number of out-of-step, and use differential angle as an auxiliary criterion to select the best opportunity to trip. When these three elements operate at the same time, the out-of-step protection will operate immediately. This new method is accurate and reliable and is not affected by system operation mode, and has been verified on RTDS simulation system.