计及发电机内电抗的链式电力系统机电扰动传播研究

Research of Electromechanical Disturbance Propagation in a Chain Power System Considering Generator Internal Reactance

机电扰动在系统中传播可能危害电力系统安全。基于计及发电机内电抗的一维链式电力系统连续体模型,研究了机电扰动传播机理。给出描述一维链式电力系统连续体模型的色散波动方程;在此基础上,利用拉普拉斯变换和留数法求得系统受阶跃功率扰动后母线电压相角增量及有功功率增量的解析解,仿真证明该解析解的正确性;在典型参数下,分析了母线电压相角增量解析解中每一项对扰动传播的影响。该解析解能够描述扰动后功率变化的整个过程,从而进一步揭示了机电扰动在电网中的传播机制。

The propagation of electromechanical disturbance in the power network may pose threat to system security. This paper studied the propagation mechanism based on a one-dimension chain power system model, and the generator reactance was included in the model. A dispersive wave equation was derived to describe the continuum model of the one-dimension chain power system. The analytic solutions of the bus voltage phase angle increment and active power increment after a step-power disturbance were solved by using Laplace transform and the residue method, and was validated by simulation. Meanwhile, the effectsof each term of the bus voltage phase angle＇s analytic solution on disturbance propagation were studied under typical power system parameters. The analytic solution obtained in the paper is able to describe the whole process of power variation after a disturbance, and further reveals the propagation mechanism of the electromechanical disturbance.