变压器宽频带局部放电在线检测技术的研究

发布时间：2018-11-27 18:42

【摘要】：变压器是电力系统最重要的设备之一,其可靠性直接影响电网的安全运行。对其绝缘性能进行局部放电在线检测,能够连续、实时的反映出变压器内部的绝缘劣化状况,是掌握变压器绝缘状况的重要手段之一。宽频带脉冲电流法检测法与常规脉冲电流法相比具有测量频带宽、灵敏度高、包含的局部放电信息量大等优点,可以更加真实地反映局部放电的原始脉冲电流特征,为采用脉冲电流波形分析的方法进行信号与噪声分离提供了可能,因此本文对其进行了研究。本文研制了一套能在变电站环境下使用的宽频带局部放电在线检测系统,包括宽频带电流传感器、工频相位发生器、宽频带信号放大器、滤波器、数字示波器和计算机。在3台三相双绕组真实变压器和1台三相三绕组模型上研究了宽频带局部放电脉冲在实际变压器中的传播规律和耦合机理,可为变压器局部放电在线监测和定位提供指导。本文利用所设计的宽频带局部放电在线检测系统采集了某地多个变电站内变压器铁芯接地线上的局部放电信号,并将每个变电站的信号进行了频谱分析,从频域内研究宽频带局部放电的规律；然后进行了基于相位分布的统计分析,并将有疑似放电的数据进行了基于等效时频法的放电类型的识别。
[Abstract]:Transformer is one of the most important equipments in power system. Its reliability directly affects the safe operation of power grid. On-line partial discharge (PD) detection of its insulation performance can reflect the internal insulation deterioration of the transformer continuously and in real time. It is one of the important means to master the insulation condition of the transformer. Compared with the conventional pulse current method, the broadband pulse current detection method has the advantages of high frequency bandwidth, high sensitivity and large amount of partial discharge information, which can more truly reflect the original pulse current characteristics of partial discharge. It is possible to separate the signal from noise by using the method of pulse current waveform analysis, so it is studied in this paper. In this paper, a broadband PD on-line detection system is developed, which can be used in substation environment, including broadband current sensor, power frequency phase generator, broadband signal amplifier, filter, digital oscilloscope and computer. The propagation law and coupling mechanism of wide-band partial discharge pulse in practical transformer are studied on three real three-phase double-winding transformers and one three-phase three-winding model, which can provide guidance for on-line monitoring and location of partial discharge of transformers. In this paper, the partial discharge signals on the core earth wires of transformers in several substations are collected by using the designed broadband PD on-line detection system, and the frequency spectrum of the signals in each substation is analyzed. The law of wide-band partial discharge is studied from the frequency domain. Then the statistical analysis based on phase distribution is carried out, and the data of suspected discharge are identified based on equivalent time-frequency method.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM855

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