断路器同步分断短路电流零点预测方法研究  

Research on Zero Prediction Method of Synchronous Breaking Short Circuit Current of Breaker

作　　者：荣文帅 蔡志远[1] Rong Wenshuai;Cai Zhiyuan(School of Electrical Engineering,Shenyang University of Technology,Shenyang,110870,China)

机构地区：[1]沈阳工业大学电气工程学院

出　　处：《电工技术学报》2019年第15期3167-3174,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金面上资助项目(51777129)

摘　　要：断路器同步分断可以有效地提高断路器分断能力和减小触头电弧磨损,是智能电器领域的发展方向之一。为实现断路器同步分断,需要对实测短路电流进行波形分解和重建,以预测短路电流过零点。该文对目前应用较广的最小二乘参数辨识和改进快速傅里叶变换两种零点预测算法进行了理论分析,建立了单相短路电流仿真模型,给含有直流衰减分量和谐波分量的短路电流信号添加不同信噪比的高斯白噪声,对含有噪声的信号进行了量化处理,模拟电网频率波动,得到了同步采样和非同步采样下短路电流离散时间序列,分别用两种算法对短路电流过零点进行了预测。此外,搭建了短路电流实测平台,对实测短路电流进行了波形分析和零点预测。对理论和实测短路电流进行零点预测的结果表明:理想状态下改进快速傅里叶算法的预测精度优于最小二乘参数辨识,但对数字化测量系统的信噪比、模数转换的有效位数和电网频率的稳定性等要求较高;最小二乘参数辨识算法对噪声和扰动等的耐受能力高于改进快速傅里叶算法。Synchronous switching of circuit breakers,as one of the promising research area of smart smart electronics,can effectively enhance switching capability of circuit breakers while reducing electric arc damage.To achieve synchronous control,separation and reconstruction of short-circuit current is required for prediction of zero crossing of short-circuit current.This paper analyzes two most commonly adopted zero-crossing prediction algorithms,parameter estimation using least square method and enhanced Fast-Fourier-Transformation (FFT) method,with simulated data.The simulated data are firstly obtained from the proposed single-phase short-circuit model.Short-circuit currents with DC attenuation component and harmonic component are then synthesized with Gaussian noise with different SNR before being digitalized.Finally,by simulating grid frequency variation,testing data for zero- crossing prediction can be then obtained as distributed short-circuit current series from synchronized and asynchronized sampling.In addition,two aforementioned algorithms are also tested for waveform analysis and zero-crossing prediction with real short-circuit current data obtained from experimental short-circuit platform.Experimental results suggest that enhanced FFT algorithm is accurate than least square parameter estimation method.However,it relies on excellent stability from grid frequency as well as strict requirement on SNR of digital measurement systems and valid bit depth of ADCs.On the other hand,least square parameter estimation method demonstrates better noise and interference immunity.

关 键 词：电流零点预测 改进快速傅里叶算法 最小二乘参数辨识 可控开断 

分 类 号：TM561[电气工程—电器]