运用电力系统稳定器对励磁系统进行相位补偿的理论与实践

Theory and Field Practice of Phase Compensation on Generator Excitation System by Utilizing Power System Stabilizer

该文针对电力系统稳定器(power system stabilizer,PSS)理论与工程之间差异的关键细节进行说明和探讨。首先简要阐述了力矩分解法分析低频振荡的基本原理,介绍了与PSS相关的关键概念及其区别。然后通过分析和仿真指出,PSS参数整定是基于发电机在功角处开环时的励磁系统相频特性,即理论值,而实测励磁系统相频特性是功角闭环时得到的。两者在系统自然振荡频率附近狭窄的频段内有很大差别,但在其余频段差别很小,因此可以通过"人工平滑"的方式由实测值得到理论值。并进一步论证了PSS参数现场整定方法的合理性。最后提出,由于发电机负荷变化时,励磁系统的理论无补偿相频特性差异很小,工程应用中在发电机负荷较大和较小时均可配置PSS参数。

The key details of the differences between power system stabilizer （PSS） theory and engineering application was illustrated and discussed. As the theory foundation, the principle of torque decomposing method which is used to analyze the low frequency oscillation was expatiated, and several important conceptions were explained. The analysis and simulation indicates that PSS parameters setting is based on the excitation system frequency characteristic as the generator power angle is open-looped, namely, the theoretical value, while the field engineering excitation system frequency characteristic is obtained as the power angle is looped. There is obvious difference between the two kinds of frequency characteristic in the narrow frequency channel nearing system natural oscillation frequency, but the difference is very small in the other channels. So theoretical frequency characteristic of the excitation system can be gotten after the field engineering value is manual smoothed. At last, a standpoint is extracted that the PSS parameters can be set not only as the generator is in big load but also in small load in the engineering application, because the variation of the theoretical frequency characteristic of the excitation system uncompensated is small when the generator power changes.