基于振荡能量的低频振荡分析与振荡源定位 （一）理论基础与能量流计算

摘要

提出了一种基于振荡能量的低频振荡分析方法。该方法通过网络中的振荡能量流评估元件的阻尼特性、定位负阻尼发电机和外施周期性扰动的位置。文中首先证明了发电机能量消耗和其阻尼转矩的一致性。然后利用广域测量信息,建立了不需要构造能量函数的网络中振荡能量流的计算公式。由于流入支路的振荡能量包含支路暂态能量的变化以及支路消耗或产生的能量,因此提出了一种计算能量流的实用方法,以减少其中的暂态能量分量,而只计算出支路消耗或产生的能量。由于系统的总能量与振幅对应,因此消耗能量的元件对振荡衰减的贡献为正,具有正阻尼,而产生能量的元件是振荡源。利用发电机的能量消耗来估计其阻尼转矩系数,与阻尼转矩分析的结果相符。利用能量流即可定位振荡源。%A method based on oscillation energy for low frequency oscillation analysis is proposed.In this method,the damping of an element is estimated,and the generators with negative damping torque and the external periodic disturbances are located based on energy flow in power networks.At first,it is proven that the energy dissipation of a generator is consistent with its damping torque.Then,based on wide area measurements,a formula to compute oscillation energy flow in the power network is constructed without constructing energy functions.Because the energy flowing into a branch is composed of transient energy variation and energy dissipation or production,a practical method for energy flow computation is proposed to reduce the transient energy component and only obtain the energy dissipation or production.Because the total energy in the power system is consistent with the oscillation amplitude,the element dissipating energy has positive contribution to oscillation damping and has positive damping,while the elements producing energy are oscillation sources.The results obtained by using energy dissipation of a generator to estimate its damping torque coefficient are consistent with the conventional damping torque analysis.In addition,the energy flow can be used to locate the oscillation sources.