电力系统稳定器(power system stabilizer,PSS)是目前抑制电力系统低频振荡最经济、最有效的办法,PSS抑制低频振荡的效果很大程度依赖于参数好坏。传统的PSS设计方法需要测量励磁系统的无补偿滞后特性,然而,这种基于在线激励的方法可能会对系统稳定性造成危害。为此,提出了一种基于相量测量单元(phasormeasurement units,PMUs)实测扰动数据的PSS参数设计方法。首先推导了单机无穷大系统线性化模型中振荡时各物理量的相位关系,再利用多信号Prony辨识得到的相位计算励磁系统的相位滞后特性,最后采用相位补偿法设计PSS参数。该方法利用电网中自有的扰动数据,不需要施加激励信号,具有很好的工程应用价值。采用贵州电网PMU实测记录的两次扰动数据进行仿真,结果显示按照提出的方法得到的PSS参数能够进一步改善相关模式的阻尼特性,提高系统的稳定性,表明了该方法的有效性。
The most effective method of damping low frequency oscillation is the use of power system stabilizers(PSSs) to control generator excitation systems,and better effect will be obtained with better PSS parameters.Traditional methods design PSS parameters by measuring the phase lag characteristic of the excitation control system when the PSS is out of running.However,the methods may decrease the stability of power system when probing signals are excited to the power system.Consequently,we propose a method of designing PSS parameters using dynamic data measured by phasor measurement units(PMUs).The phase relationship of the Phillips-Heffron model of a single-machine infinite-bus power system under the oscillations is firstly deduced.Then the phase results of multi-signal Prony identification are used to obtain the phase lag of the excitation control system.Finally,the phase compensation method is utilized to design PSS parameters.The presented method uses the dynamic data of the power system and does not need exciting signals,so it has very good applicable value.Simulations on Guizhou power system based on dynamic data measured by PMUs demonstrate the advantages of presented method.