电力系统软件测频的改进方法

An improved method of frequency measurement for power system

频率是电力系统中一个非常重要的特征量,同时频率也是继电保护、测控等继电保护装置进行相应动作的重要判据,因此频率测量是电力系统测量装置中十分重要的环节。电力系统最常用的软件测频方法为离散傅氏算法,采用分段三次Herm ite插值对离散傅氏测频算法进行改进。所提出的新改进方法具有精度高,计算量相对不大,实时性好的优点。通过数值仿真,分析了本改进方法的时间响应数据窗、绝对误差和谐波对本方法的影响。理论和仿真结果都证明本方法的实用性好。

Frequency is a very important characteristic quantity in power systems, and an important criterion for relay protection, measurement and control, etc. So Frequency measuring plays a very important role in power system measuring equipments. Discrete Fourier algorithm is a common software frequency measurement in power system, this paper describes a new improved method which uses Piecewise Cubic Hermite Interpolating Polynomial to enhance the effect of Discrete Fourier algorithm. A useful method for frequency measuring is proposed, which has the advantages of high precision, small computation and a good real time performance. By numerical simulation, this paper gives the data windows of time response, the absolute error and the effects of harmonics, The results prove that the method has some practical value.