一种新型配电网电容测量系统的设计.pdf

一种新型配电网电容测量系统的设计 王宗省 孟秀芝 (山东科技大学机械电子工程学院, 青岛 266510) 摘 要: 为了确定配电网络的对地分布电容, 设计了一种基于 3 个频率信号注入法的配电网电容测量系统, 给出了系统测 量原理及硬件系统的构成 , 介绍了用集中电容来模拟配电网电容的测量实验 , 提出了用扫频法测得的模拟实验结果结合 MATLAB 仿真技术确定最佳注入信号频率的方法, 探讨了注入信号的频率对测量精度的影响。注入特定的 3 个频率恒流信号, 测试模拟实验中的集中电容, 测量结果的相对误差在 2%之内。测量过程不涉及高压侧, 操作方便, 有很好的应用前景。 关键词: 配电网; 电容电流; 注入信号; MATLAB 仿真技术 中图分类号: TM835.2 文献标识码: A 国家标准学科分类代码: 460.4030 Design of new measurement system for capacitance current in distribution network Wang Zongsheng Meng Xiuzhi (College of Mechanical and Electronic Engineering, SUST, Qingdao 266510, China) Abstract: To measure the capacitance current of distribution network, the measurement system is designed based on three signals with different frequencies injected into distribution network by the open delta of PT. The measuring principle and the structure of the system hardware are recommended. The measurement experiment with lumped capacitors to simulate the distribution network of capacitance is introduced. A method is presented to enhance the accuracy of the measurement. The experimental data achieved by frequency sweeping is used in the MATLAB simulation to determine the optimal frequency. The influence of the frequency value of signal on accuracy of measurement is discussed. Three current signals with different frequencies are injected into the lumped capacitors by the single phase of PT and the relative error of measurement results is less than 2%. Being cut off from the high pressure side, the measurement process becomes more safety and easier. It has high practical value and broad application prospect. Keywords: distribution network; capacitance current; injected signal; MATLAB simulation