基于传递函数矩阵频域特性的原动机侧强迫振荡源定位方法

Location Method for Forced Oscillation Source in Mechanical Parts Based on Frequency-domain Characteristics of Transfer Function Matrix

原动机和调速系统(原动机侧)的周期性扰动是引发强迫振荡的主要原因。基于扩展的多机Phillips-Heffron模型,推导了从原动机侧扰动到发电机机械功率的传递函数矩阵,并证明该矩阵在正常参数范围内是主对角占优的。据此,对于原动机侧周期性扰动、故障及参数异常等引发的振荡,具有最大机械功率功率谱密度的发电机原动机及调速器就是可能的扰动源;在考虑了励磁和负荷侧扰动源对机械功率的影响后,推导了从励磁和负荷侧扰动到机械功率的传递矩阵,从理论上证明了将机械功率功率谱密度最大的发电机定位为扰动源是准确合理的。10机39节点算例和华北电网算例验证了所提定位方法的有效性与可行性。

Periodic disturbances in prime movers and governors(mechanical parts)are major causes for forced oscillations. Based on the Phillips-Heffron model of multi-machine systems, the transfer function matrix from disturbances in mechanical parts to mechanical power is derived, which is proven to be inherently diagonally dominant with equipment parameters in normal range. According to the property, the mechanical part of the generator whose mechanical power has the largest power spectral density is the possible oscillation source for oscillations caused by periodic disturbances, malfunctions and parameter abnormities in mechanical parts. Meanwhile, the influences of periodic disturbances in loads and exciters on mechanical power are considered. The transfer function matrices from loads and exciters to mechanical power are also derived, showing that it is reasonable to identify the generator with the largest power spectral density of mechanical power as oscillation source from the theory aspect. Demonstrative examples of 10-machine 39-bus system and North China Power Grid show the effectiveness and simplicity of the proposed location method.