基于介质响应电流频变特性的油纸绝缘受潮状态评估方法  

Evaluation Method of Oil-Paper Insulation Damp State Based on the Frequency-Dependent Characteristics of Dielectric Response Current

作　　者：夏源[1] 杨丽君[1] 吕晓露 汪可 李金忠 Xia Yuan;Yang Lijun;LüXiaolu;Wang Ke;Li Jinzhong(State Key Laboratory of Power Transmission Equipment Technology,Chongqing University,Chongqing,400044,China;China Electric Power Research Institute,Beijing,100192,China)

机构地区：[1]输变电装备技术全国重点实验室(重庆大学),重庆400044 [2]中国电力科学研究院有限公司,北京100192

出　　处：《电工技术学报》2024年第11期3444-3456,共13页Transactions of China Electrotechnical Society

基　　金：国家电网公司总部科技项目资助(5200-202155590A-0-5-GC)。

摘　　要：油纸绝缘受潮状态的准确评估对于电力设备安全稳定运行至关重要,该文研究并提出了一种以介质响应电流幅值I_(m)随激励电压频率f变化为特征的油纸绝缘受潮评估新方法。试验测试了不同水分含量油纸绝缘样品在频率f为0.01~50 Hz正弦激励电压下的f-I_(m)特性,并对I_(m)按照其最小值进行归一化处理得到f-I^(*)曲线。结果表明:在双对数坐标下,随着受潮程度增加油纸绝缘的f-I^(*)曲线会由干燥时的一条直线逐渐变为一条下凹的曲线。进一步提出将50 Hz处的I^(*)值I^(*)_(@50Hz)作为特征参量,用于量化油纸绝缘水分含量,并在实验室模型和实际油浸式设备上验证了该方法的有效性。与传统利用频域介电谱诊断油纸绝缘受潮的方法相比,该文所提特征参量与水分含量的量化关系受绝缘结构差异和油纸绝缘聚合度变化的影响较小,在设备绝缘结构和老化状态信息缺失的情况下具有更好的普适性。另外,该方法所需测试时间仅约100 s,具有高效、准确和便捷的特点。Moisture in the oil-paper insulation is an important cause of performance degradation in power transformers,and accurate assessment of the moisture state of the insulation inside the equipments is important to ensure its safe operation.At present,the method of projecting the moisture content of insulating paper according to the moisture content in oil has led to great errors in field application due to the complicated influencing factors.In recent years,the insulation condition diagnosis technology based on dielectric response test method has received wide attention,and some characteristic parameters and evaluation methods have been proposed,but the accuracy of the evaluation results is greatly influenced by the differences in transformer insulation structures and cannot yet meet the needs of practical engineering applications.Based on the previous research results,this paper further explores the influence of moisture on the response current characteristics of oil-paper insulation,and aims to propose an efficient evaluation and diagnosis method of insulation moisture state that is less affected by the difference of insulation structure and easy to implement in the field.First,oil-paper insulation samples with different moisture contents and different polymerization degrees were prepared.In order to measure the response current signals of the oil-paper insulation under voltage excitation of different frequencies and amplitudes,a response current test system for oil-paper insulation was built.The response currents of the samples were tested in the frequency range of 0.01 Hz to 50 Hz.The response current amplitude at 0.01 Hz was used as the reference value,and the response current amplitude at different frequencies was normalized to obtain the f-I^(*)curve.The f-I^(*)curve of oil–paper insulation will change from a straight line when dry to a concave curve as the moisture content in the paper increases,while the f-I^(*)curves of oil–paper insulation with different polymerization degrees basically overlap.When th

关 键 词：油纸绝缘 频率 响应电流 水分含量 

分 类 号：TM855[电气工程—高电压与绝缘技术]