励磁系统参数时域辨识

文章以沙岭子电厂7号发电机为例, 以建立BPA自并励励磁系统模型参数为目的, 介绍了一类基于时域分段线性多项式函数(PLPF)的辨识方法。PLPF法是一种将传递函数模型经微分方程转化为多重积分方程, 再利用线性多项式插值函数来逼近原函数, 将多重积分方程转换为代数方程,然后利用动态响应的离散数据拟合函数进行分段处理的方法。根据自并励励磁系统模型输入输出时域动态响应数据, 采用该方法直接对沙岭子电厂7号机的励磁系统进行相关参数辨识。这就给出了将一套非标准励磁系统通过参数辨识转换为中国电力科学研究院开发的仿真软件BPA下标准模型的实例, 最后进行了仿真验证, 结果证明了时域PLPF法辨识结果正确, 可以用来进行发电机组励磁系统参数的辨识。

Time Domain Parameter Identification in an Excitation System

This paper introduces a method of parameter-identification for an excitation system based on PLPF in the time-domain.This method is mainly used for identifying the time-domain parameters in a model of a bus fed static excitation system in BPA,which is a software package developed by the China Electric Power Research Institute. A living example of Generator No.7 at Sha-ling-zi Plant was used in the illustration of the method. PLPF is a method that consists of the following steps:1)Transforms the transfer function into a multi-integral equation;2)Curve fitting the original function by using a linear polynomial function;3)Converting the multi-integral equation into an algebraic equation; 4) Piecewise processing by fitting the algebraic equation using the discrete data from the dynamic response. The proposed method is used for directly identifying the relev ant parameters in the excitation system in the Generator No.7 at Sha-ling-zi Plant. The data used in the identification are based on the time-domain input and output dynamic responses using the model of the bus fed static excitation systems. This practice illustrates an example of converting a non-standard excitation system into a standard excitation system by this parameter identification method. The identification method has been verified by a simulation. The results convince that the parameters identified by the time-domain PLPF parameter identification method are correct and the proposed method can be used for identification of parameters in the excitation systems of generators.