10kV电网过电压在线监测装置的研制及波形分析

Development and result analysis of on-line device for monitoring overvoltage in 10kV power system

本文介绍了监测10kV电网大气过电压和内过电压的在线监测装置的设计原理及方法,分析了用于过电压信号采集的分压器、前置硬件电路、数据采集卡、波形数据采集和分析软件的设计思想和关键技术。通过对长期的现场实测波形数据分析表明,本装置取得满意效果。

Some overvohage accidents usually occur in lOkV power system, and it is difficult to analyse its causes using usual fault oscilloscope. In this paper, a new device to monitor lightning impulse overvoltage and inner overvohage in lOkV power system is presented. Design principle and key technique are discussed. Capacitance-resistance divider with excellent performance of frequency response is designed to capture overvohage, and it is more suitable than potential transformer to transfer lightning impulse overvohage according to result of square-wave response. Special data acquisition technique is introduced, including double buffer,suitable size of memory and pre-trigger. Data acquisition software and waveform analysis software are independent to easily analyse waveform in different computer. The precision of the device based on 50Hz Sine and standard lightning impulse is satisfied. From long-time operation, results indicate that the performance of the device for monitoring overvohage is excellent and overvohage captured is useful to analyse forming causes of overvohage accident.