氧化锌避雷器泄漏电流网络化在线监测系统

【作者】 邓维；

【导师】 彭建春；

【作者基本信息】 湖南大学 ， 电力系统及其自动化， 2002， 硕士

【摘要】 氧化锌避雷器是一种重要的过电压保护电器，由于它具有优越的非线性与保护性能而在电力系统中得到了广泛的应用。然而氧化锌避雷器没有放电间隙，在长期的运行电压作用下，其阀片会逐渐劣化；或由于避雷器本身结构不良而受潮。这些都将导致避雷器泄漏电流的增加，严重时还会导致热崩溃，引发电力系统事故。传统的一年一度的停电预试具有较大的缺陷，因此有必要对氧化锌避雷器的运行状况进行在线监测。 本文对氧化锌避雷器运行电压下的泄漏电流、尤其是阻性电流分量的监测技术进行了研究。在综合现有监测方法的基础上，基于阻性电流基波法提出了一种改进的基波法。该方法不仅能排除电网谐波成分对测量结果的影响，使测试结果稳定可靠，而且通过获取同相CVT泄漏电流信号作为参考信号来计算相位角、用综合相对比较法来处理监测数据，提高了测量的准确度。 本文的方法不仅能够实现测试仪与主回路之间的电气隔离，而且能够较好地跟踪避雷器泄漏电流波形，从而为正确判断避雷器的运行状况提供了保障。在数据处理方面，采用89C52单片机微机系统，可准确地进行数据采集及分析计算。与目前存在的其它方法相比，具有结构简单、性能可靠的特点，更加适用于在电磁场干扰很强的变电站内使用。 随着网络化技术的发展与电网管理信息系统(MIS系统)的完善，本监测系统通过MODEM上网可以将测试数据传送到远方服务器。目前，该监测系统已经在我省500kV云田变电站挂网运行。本系统可以在近测、遥测、自动测量三种方式间自由选择，它必将为促进电力系统实施状态检修起到积极作用。更多还原

【Abstract】 The ZnO surge arresters are important over-voltage protection devices. They are widely used in electric power system due to their excellent nonlinear and high surge absorbing capability. Considering that the ZnO surge arresters have canceled gaps, they will deteriorate gradually under operating voltage. Some of them will be moistened because of structure problems. All these can lead to increasing of leakage current of. the arresters. The limitations are inevitable in conventional yearly preventive test of ZnO surge arresters. So it is in need increasingly to research the on-line monitoring technique for the arresters.In this paper, the on-line monitoring technique of leakage current, especially of the resistive leakage current through the ZnO surge arresters under operating voltage is discussed.The existing different monitoring methods are investigated at fist. A new measuring method named resistive basic harmonic current measuring method is introduced. By applying this method, the influence of harmonics in the system voltage on the measuring result may be minimized. So the measuring result may be more reliable. Something is done to improve this method, including selection of reference signal and application of the synthetic relative measuring method. At the same time, this new method can not only isolate system and the instrument electrically, but also transmit the current signal linearly. In respect of data processing, the 89c52 microprocessor is used so that the data may be calculated more accurately. Compared with other methods, it is better used in the electrical station as it has some other feature such as simple structure,high anti-interference ability and reliable performance.With the development of the network technology and the MIS of electric power, test data can be transmitted to the server far away through MODEM. It is convenient and realizable. A practical on-line monitoring system has been developed and operated in the 500 kV Yuntian power station, Hunan Province. Test results show that the monitoring system is effective. We are sure that this on-line monitoring system will play a great role in the condition based maintenance.更多还原