多机电力系统PSS参数优化新方法

Novel approach of parameter optimization for multi-machine power system stabilizers

机械回路谐振引起了励磁系统频率特性曲线出现"波峰"和"波谷",造成现有方法不易准确测量或计算励磁系统相位滞后角.为此,本文提出一种新的多机系统PSS参数优化方法.首先,重新定义基于多机模型的励磁系统相位滞后角,并推导出相应的计算公式,基于新定义的计算方法不再受机械回路谐振的影响,可以得出更合理的计算结果.然后,在PSS增益整定时,将问题描述转化为多机系统部分输出量反馈的优化模型,通过求解Levine-Athans方程组得到最佳PSS增益.最后将所提方法应用于一个8机电力系统,与传统方法比较后,表明电力系统阻尼特性得到进一步改善.

Frequency characteristic curves of excitation systems always arise or sink sharply at the frequency of mechanical loop-resonance. This is the reason why phase-lagging angles of excitation systems are difficult to be measured or calculated accurately. In this paper, a novel method of power system stabilizer（PSS） optimization for multi-machine system is presented. Firstly, based on the multi-machine power system model, a new definition of phase-lagging angles for excitation systems is built, and the corresponding algorithm is derived simultaneously. The proposed definition and its algorithm produce more reasonable calculation results, which are not influenced by the resonance of mechanical loops. Secondly, The mathematical model used for setting PSS gain can be described by another control problem, which optimizes partial feedback variables in a multi-machine power system. So, the best gain of PSS is obtained by solving Levine-Athans equations. Finally, using an eight-machine test system, the proposed approach and traditional method are compared. Simulation result shows that the new method mentioned in this paper is helpful to damping performance.