摘要
局部放电是加速聚合物绝缘老化及失效的重要因素,局部放电产生的电荷会在电场作用下发生输运行为,这种局部放电电荷后续行为表现为局部放电后续电流。局放后续电流会造成介质附加损耗和绝缘损伤,影响聚合物材料的使用寿命,然而其产生机理尚不完全清楚。为此以环氧树脂为例,在研究局部放电后续电流测量原理的基础上,建立了一种总积分电流中消除外施电压引起的位移电流和电导电流以及局放平均放电电流,从而得到局部放电后续电流的测量方法。在实验室内搭建了局放后续电流测量系统,测量环氧树脂在沿面及气隙放电形式下的局放后续电流,并计算其放电电荷量与后续电流电荷量。试验结果表明,基于该测量系统,在两种放电条件下均能测量到明显的局部放电后续电流,其本质是局部放电后续电荷在电场作用下,在介质内部进行输运而产生的电流。同时提出了考虑外施电场及空间电荷场驱动的局放后续电流模型,该模型有助于解释交流电场下局部放电过程中复杂的电荷动力学过程。此外,评估了该电流对聚合物材料老化的影响,对聚合物局部放电老化机制的研究具有重要意义。
Partial discharge is an important factor to accelerate the aging or failure of polymeric insulation.The charges generated by partial discharge will be transported under the action of electric field,and the subsequent behaviors of partial discharge charge perform as the subsequent current of the partial discharge.The subsequent current of PD will cause dielectric loss and insulation damage,and affect the service life of polymer materials.However,its generation mechanism is not completely clear.Taking epoxy resin as an example,we first attempted to observe the subsequent current induced by PD and describes its dynamics under AC electric field.We designed a measurement system to acquire the subsequent current component after eliminating the displacement current,intrinsic conduction current and PD current from the total current flow.The measurement system was built in the laboratory to measure the subsequent current of PD of epoxy resin under the surface discharge and air-gap discharge,and to calculate the PD charge and subsequent current charge.The results show that,based on the measurement system established in this paper,an obvious subsequent current of PD can be measured under both discharge conditions.The essence is that the subsequent charge is transported inside the medium under the action of an electric field.A preliminary model considering space charge and driven by electric field is proposed which may facilitate the understanding and analysis of the complicated charges dynamics during PD at AC electric field.Moreover,the impact of the subsequent current on the aging of polymer materials is evaluated,which is of great significance to the study of the mechanism of partial discharge aging of polymers.
作者
张志斌
任明
宋波
夏昌杰
范文杰
庄添鑫
ZHANG Zhibin;REN Ming;SONG Bo;XIA Changjie;FAN Wenjie;ZHUANG Tianxin(State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2022年第6期2215-2225,共11页
High Voltage Engineering
基金
国家重点研发计划(2018YFB0904400)。
关键词
局部放电
聚合物绝缘
电流测量
电荷输运
老化机制
partial discharges
polymer dielectrics
current measurement
charge transfer
aging mechanism
