基于阻尼转矩分析的电力系统低频振荡源定位

Power system oscillation source location based on damping torque analysis

准确定位低频振荡参与机组并采取有效的控制措施以提高系统阻尼、快速平息系统振荡是大电网安全稳定运行的重要保障。为此,提出了一种基于总体最小二乘-旋转不变技术的信号参数估计(TLS-ESPRIT)和阻尼转矩分析(Damping Torque Analysis,DTA)方法进行低频振荡发生源定位的方法。该方法利用TLS-ESPRIT对发电机组的有功出力、角速度、功角信号进行模式分解,提取发电机高度参与的振荡模式,采用最小二乘拟合方法计算发电机高度参与振荡模式的阻尼转矩系数,然后根据阻尼转矩系数判定发电机是否为该振荡模式的振荡源。分别以4机2区和10机39节点系统为例进行仿真验证。仿真结果表明,所提出的振荡监测方法能够准确定位电力系统低频振荡源,且通过振荡源对其自身的控制能够有效地平息系统中的低频振荡现象。

Locating low frequency oscillation sources exactly and taking appropriate control measures to enhance system damping and suppress system oscillations are an important guarantee for the secure and stable operation of power grids. Therefore, this paper proposes an effective oscillation source location method based on a total least squares-estimation of signal parameters via rotational invariance techniques （TLS-ESPRIT） and damping torque analysis （DTA） for the power systems. In this method, the dominant oscillation mode of each generator is extracted from measured signals （e.g. rotor speed, rotor angle, and active power） at its side by means of TLS-ESPRIT, and then corresponding damping torque coefficient can be obtained through the least square fitting method to determine whether the generator is the oscillation source of this oscillation mode. Finally, case studies are carried out on the 4-machine 2-area system and 10-machine New England test system, respectively. Simulation results indicate that the proposed locating method can accurately locate the power system oscillation source, by which low-frequency oscillation can be effectively restrained using local control measures.