摘要
为实现换流变压器绝缘纸机械强度的无损检测及评估变压器的绝缘寿命,首先在100℃下对绝缘纸进行了频率为50 Hz、振幅为0.57 mm,老化时间为35 d的一系列加速机–热老化实验。其次,测量了不同老化时间的试品在10–3~103 Hz范围的频域介电谱(FDS)特性及其抗拉强度(TS)。通过对试品tanδ–f曲线特性进行分析发现,低频段可作为表征试品老化程度的特征频段。同时发掘了特征频率下不同老化时间试品的介质损耗因数和对应的抗拉强度间存在的负指数关系,并利用实验数据佐证了此关系的正确性,据此可实现绝缘纸机械强度的无损检测以及老化状态的有效评估。最后,发展了基于FDS的绝缘纸剩余寿命预估判据,可有效评估绝缘纸的剩余寿命。该结论可为变压器绝缘纸机械特性的无损检测及寿命评估提供理论依据。
To realize nondestructive tests for mechanical strength of converter transformer insulation paper and residual lifetime evaluation of transformer insulation,firstly,a series of accelerated mechanical-thermal aging(MTA)experiments were performed in this work under the conditions of 100℃,the amplitude of 0.57 mm,the frequency of 50 Hz and the aging duration of 35 d.Secondly,the frequency domain spectroscopy(FDS)characteristics and tensile strength(TS)of cellulose insulation paper specimen were measured and determined when the frequency scope of the FDS tests ranged from 1 m Hz to 1 kHz.By analyzing the characteristics of tanδ-f curves,it was found that the low frequency band of tanδ-f curve could be selected as the characteristic frequency band to indicate the degradation status of the specimen.Moreover,the negative exponential relationship between the dielectric loss value and the corresponding tensile strength of the specimen with different degradation status under the characteristic frequency was explored,and the validity of this proposed relationship was verified by the experimental data.Based on the above relationship,the nondestructive testing of mechanical strength and the effective evaluation of degradation status of insulation paper could be achieved.Finally,the residual lifetime prediction criterion based on FDS was developed,by which the insulation lifetime of the specimen could be evaluated effectively.The conclusion can provide a theoretical basis for nondestructive tests and lifetime evaluation of the mechanical properties of the insulation paper within power transformers.
作者
李长云
王一帆
于永进
孔旭
程学珍
LI Changyun;WANG Yifan;YU Yongjin;KONG Xu;CHENG Xuezhen(College of Electrical Engineering and Automation,Shandong University of Science and Technology,Qingdao 266590,China;School of Electrical Engineering and Automation,Qilu University of Technology,Jinan 250353,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2020年第10期3576-3582,共7页
High Voltage Engineering
基金
山东省重点研发计划(2019GGX102049)
山东省自然科学基金(ZR2017MEE078)。
关键词
机–热协同老化
纤维素绝缘纸
频域介电谱
抗拉强度
寿命评估
mechanical-thermal synergy aging
cellulose insulation paper
frequency domain dielectric spectroscopy
tensile strength
life evaluation
