电力变压器铁心接地电流在线监测系统研究

【作者】 刘树珍；

【导师】 杨志坚；

【作者基本信息】 山东大学 ， 电气工程， 2011， 硕士

【摘要】 电力变压器是电力系统中最重要的电气设备之一,其是否安全稳定运行将影响到供电可靠性和系统的正常运行,因此,对电力变压器运行状态进行实时在线监测具有重要意义。在电力变压器运行过程中,为了防止因铁心点接地导致接地电流超标而造成的铁心过热和烧毁故障,设计了一种基于GSM无线传输技术的变压器铁心接地电流在线监测系统。在本文中,由电流传感器获得电信号,经量程自动切换模块,再由MAX197芯片进行A/D转换,使数字信号进入CPU；CPU控制LED进行电流显示,用户可根据自身需要对键盘进行相关操作及切换显示。该系统能够实现对变压器铁心接地电流的实时或定时监测和历史数据的存储,当监测到接地电流超过国家标准后发出报警信号,并根据电流的大小实现限流电阻的自动投切,最终将接地电流限制在规程要求的范围内。更多还原

【Abstract】 The power transformer is one of the most important electrical equipments in the power system, whether it can run safely and stably or not will affect the reliability of the power supply and the normal operation of the system. So a fixed-time or real-time online monitoring of the running state of the transformer is very important.In the working process of the transformer, multi-point grounding of the transformer core could lead to too big grounding current which can burning the core. In order to prevent burning fault of transformer core, an online monitoring system based on GSM wireless communication technique of the current in the grounding loop of the transformer core is introduced. In this paper, the automatic switch range circuit can process the signal which comes from the current transformer to ensure the accuracy of the data. When the chip MAX197 finish the convert of analog to digital, the signal goes in to the CPU(Central Processing Uint). CPU can control the LED module to display the current. And users can operate the keyboard according to their needs, for example, setting the time interval of sending current value from CPU to cell phones, the warning value of the current and the short message center number.This system could real-time monitor the grounding current of the transformer core and store the historical data. When the grounding current exceeds the national standard, the system will generate an alert signal and control the resister automatically, which limited the current in the demand of operation standard.更多还原