【作者】 王磊；

【导师】 严干贵；

【作者基本信息】 东北电力大学 ， 电力系统及其自动化， 2006， 硕士

【摘要】 近几年来随着城市电网的发展,供配电网中电缆线路日益增多或加长,使得电网对地电容电流随之增大,远远超过规程要求,需要装配消弧线圈。而准确测量系统对地电容电流是决定装设消弧线圈与否和正确选择消弧线圈容量的依据,也是消弧线圈准确补偿的依据。本文主要围绕系统对地电容电流测量展开研究。本文首先对谐振接地系统的基本工作原理进行了深入的研究,对现有的用于各种自动跟踪消弧补偿装置的电容电流测量计算方法进行了综合的比较分析。分析表明扫频法测量系统电容电流具有较高的测量精度,并且适用于各种形式的消弧线圈,因此本文依据扫频法研制电容电流自动测量装置。基于扫频法电容电流自动测量装置包括扫频信号源和控制器两部分。扫频信号源是一个基于IGBT单相全桥逆变器,其主要功能是发出频率随时间变化的方波信号;控制器是在高性能单片机C8051F020基础开发的,实现数据采集、谐振点判断、结果显示和远程通讯等功能。在PSCAD平台上搭建了的扫频法测量电容电流的仿真系统,验证了这种方法的可行性。在动模实验室对自动测量装置进行了试验,装置的测量误差在1%以内,10ms左右即可完成电容电流测量,表明基于扫频法电容电流自动测量装置具有很高的精度和良好的实时性。更多还原

【Abstract】 Recently power cables in the distribution electric power network are used more than ever, and the capacitive current between lines and the ground is rose with the development of the city. It is recommended to install the Arc Suppression Coil when the capacitive current is greater than the permitted value 10 A in the distribution network. Just to know the exact value of capacitive current, the Arc Suppression Coil can do the right act.The paper has carried on deep studies to resonance ground system and compensation principles and analyzed various methods of capacitive current calculation of the automatic Arc Suppression Coil. The method of scanning frequency has been shown that it is more accurate than others and it can be used for all kinds of the Arc Suppression Coils, so the method of scanning frequency is chosen. The capacitive current measuring unit is composed of the signal generator and the controller. The signal generator is a voltage source inverter with IGBT, which produces square-wave output voltage with variable frequency. The four driving signals of IGBT are generated by the controller based micro-chip C8051F020. The controller is also used to sample the analog signals, to decide the resonance frequency, to show the result, and to communicate with computers.The simulative system is carried on in PSCAD/EMTDC. It is shown that the method of scanning frequency is feasible. The test is conducted in the laboratory and the result of the experimentation show that the calculation the capacitive current is vary approach to the real capacitive current and the time of the whole course is only 10 ms.更多还原