【作者】 胡涛；

【导师】 程养春；

【作者基本信息】 华北电力大学(北京) ， 高电压与绝缘技术， 2016， 硕士

【摘要】 对变压器绝缘性能进行在线监测,能够实时、连续地反映出其内部的绝缘劣化状况,是掌握电力变压器绝缘状况的重要方法之一,对变压器的局部放电进行实时在线监测,可以判断变压器的绝缘状态,是实现变压器状态维修的可靠手段,能够指导制定有效可行的检修计划,以防发生严重的事故,对变压器自身和整个电力系统的安全、可靠、经济、稳定运行有十分重大的意义。本文对变压器套管耐受过电压的时域和频域特征进行了分析计算,计算了变压器发生严重局部放电时从套管末屏接地线上流过的电流大小,确定了不同电压等级下套管末屏接地线上流过的工频泄漏电流大小,研究了变压器套管的电容的频率特性。研制了用于变压器局部放电在线监测用的宽频带电流传感器、多功能变压器套管在线监测传感器以及基于罗氏线圈原理的柔性电流传感器,并对三种传感器的性能进行了离线测试和分析。在220kV单相变压器平台高压套管末屏接地线、低压套管、中性点接地线、铁芯接地线位置分别安装本文研制的三种变压器在线监测传感器,在变压器内部安装悬浮放电模型,在额定电压等级下通过悬浮放电模型模拟真实放电信号,通过在线监测各位置传感器采集到的放电信号,分析并验证了传感器的监测性能及可靠性。更多还原

【Abstract】 Online monitoring of transformer insulation performance can reflect its internal insulation degradation condition in real time, continuous. And it’s one of the important methods to acquire the condition of power transformer insulation condition. Online monitoring of transformer partial discharge in real-time can judge the insulation state of transformer, and it’s also the reliable means of transformer state maintenance, and can guide the effective maintenance plan. The online monitoring can avoid serious accident of transformer. The online monitoring of partial discharge has very important significance for the whole power system safe, reliable, economic and stable operation.In this paper, we analysis and calculate the over-voltage of transformer by time domain and frequency domain, and we also analysis and calculate the current flow through bushing tap grounding wire which caused by serious partial discharge in transformer. By calculation we get the power frequency leakage current flow through bushing tap grounding wire in different voltage class. Transformer partial discharge on-line monitoring current sensor of wide band has been designed. We researched the frequency characteristic of the capacitance of transformer bushing. We also developed a multi-functional current sensor which can be installed in transformer bushing tap. A telescoping sensor installed in the root of transformer bushing which is based on the principle of Rogowski coil has been designed. We tested and analyzed three kinds of sensor’s performance.Put the developed sensor in the platform of 220kV single-phase transformer. Installation site is high voltage bushing tap grounding wire, low voltage bushing, neutral point grounding wire, iron core grounding wire We install suspended discharge model in transformer internal, through monitor suspended discharge signal produced by model under rated voltage grade, By Analysis the discharge signals we verified the performance and reliability of sensors.更多还原