计及保护信息的电力系统暂态稳定裕度解析算法

An Analytic Method for Power System Transient Stability Margin Considering Protection Information

电力系统暂态稳定裕度与故障因素息息相关,保护动作信息包含故障类型、故障位置以及故障持续时间等有效信息。该文提出一种计及保护信息的暂态稳定裕度解析算法。首先,计算不对称短路的附加阻抗,建立含附加阻抗的多机系统网络简化模型。然后,将转子运动方程等效为单机无穷大母线系统形式,提出发电机聚合功角的分段模型,在此基础上,推导暂态稳定裕度解析表达式。利用在线获取的保护动作信息,快速计算故障后系统的暂态稳定裕度,并通过求取暂态稳定裕度的偏导,分别分析不对称故障下故障位置和故障持续时间对暂态稳定裕度的影响。最后,在四机两区系统和新英格兰系统中进行仿真分析,仿真结果证明了该方法的准确性和有效性。

The transient stability margin of power system is closely related to the fault factors. The protection information includes effective information such as fault type, fault loca tion and fault duration. This paper proposes an analytical method for calculating transient stability margin considering protection information. Firstly, the additional impedance of unbalanced fault is calculated, and the simplified model of multi-machine system network with additional impedance is established. Then, the rotor motion equation is equivalent to the one-machine infinite-bus system, and the piecewise models of generator aggregate power angles are further put forward. On this basis, the analytical expression of transient stability margin is derived. The transient stability margin of power system after fault can be quickly calculated by the protection information obtained online. And the effects of fault location and fault duration on the stabilit y margin under unbalanced fault are analyzed by calculating the partial derivative of the stability margin expression. Finally, the simulations are carried out in the four-machine two-area system and the New England system, respectively. The accuracy and effectiveness of the proposed method are verified by the simulation results.