摘要
瓷绝缘子复杂多样的劣化形式及其表面污秽均会影响红外检测结果,从而造成对于劣化绝缘子的误判或漏判,给电力系统的安全稳定运行带来严重威胁。目前针对不同污秽作用下绝缘子串的发热特征及污秽对劣化绝缘子红外检测结果的影响少有研究。为此该文结合现场试验及有限元仿真研究了劣化位置、劣化阻值以及不同污秽对瓷绝缘子串发热规律及其红外成像的影响。研究结果表明:绝缘子串中任意一片绝缘子的温升随着其内阻的减小呈现先升高后降低的趋势。干燥污秽对劣化绝缘子发热的影响可忽略不计,而湿润污秽对发热的影响与劣化绝缘子在串中的位置有关,温度差值变化率最小仅有37.9%。在由表面固体污秽(A类污秽)和盐雾(B类污秽)构成的污秽中,雾水电导率对染污附盐密度具有附加作用,表面轻度污秽时其对绝缘子温升的影响大,重污秽时影响较小。在实际工程应用中,应选择绝缘子背风侧作为红外观测点,且不考虑相对湿度大于90%的情况。
During the long operational time,porcelain insulators are subjected to a synergistic effect of the electrical,thermal,mechanical stresses,and environmental factors,which causes insulation degradation and lead to low and zero resistance insulators.Compared to traditional methods,infrared imaging has been widely used in the detection of deteriorated insulators and surface contamination because of its advantages of non-stop operation,non-contact and anti-electromagnetic interference.However,there is limited research on the impact of contamination on the heating characteristics of degraded insulators.Moreover,there is a lack of research on the effects of different types of contamination(category A and category B)on the heating characteristics of the insulators and the infrared detection of degraded insulators.In response to the above issues,the effects of contamination level,deterioration resistance and the location of deteriorated unit on infrared detection of the insulators were investigated through field tests and simulation analysis,obtaining the heating patterns of deteriorated insulators under different pollution conditions.Firstly,the relationship between temperature rise,deterioration and surface contamination was explored through a heating model of porcelain insulator.Secondly,a test platform was built to simulate the operating conditions of 110 kV insulators,and the infrared imaging patterns of insulator strings were analyzed by changing the level of contamination resistance of deteriorated insulator,and the position of degraded insulators in the string.Finally,a thermal-electric coupling model of the insulator was established using finite element method to analyze and calculate the temperature distribution of insulator strings under the combined effects of dielectric loss,conduction current and heat conduction.This model is then used to validate the experimental results.The results show that the temperature rise of the insulator in the string initially increases and then decreases with the decrease in its resistance.The maximum temperature rise and temperature growth rate of degraded piece with the same resistance value located at the high-voltage end are higher than those of degraded piece located at the medium-voltage end and the ground end,with temperature change rates of 0.093,0.04 and 0.06,respectively.The overall temperature of steel cap increases with the increase in category A contamination.When the surface wet contamination is relatively light,the temperature variation rate range of each piece in the string is 0.014~0.107,while under severe wet contamination,it ranges from 0.087 to 0.12.The conductivity of fog water(category B contamination)has a significant impact on the temperature rise of the insulator,which increases with the increment of fog water conductivity.Taking the temperature rise under no salt fog condition as the benchmark,the overall average temperature change rates under fog water conductivities of 0.6,2.2 and 4.1 S/m are 54.9%,101.2%and 153.9%,respectively.The following conclusions can be drawn from the test results and simulation analysis:(1)The impact of dry contamination on the heating of deteriorated insulator is negligible.Under conditions of fixed category B contamination,the effect of category A wet contamination on heating is related to the position of deteriorated piece in the string.Furthermore,as the degree of wet contamination increases,the temperature of each piece tends to be consistent.(2)Fog water conductivity(category B contamination)has an additional effect on salt deposit density,which further affects the temperature rise of the insulator by increasing the number of conductive ions.There is a saturation phenomenon in insulator temperature rise in salt fog environments.(3)The excessive humidity can cause disordered temperature changes on the insulator surface,therefore,humidity greater than 90%is not considered during the detection.The leeward side,with small amount of contamination,is selected as the infrared observation position to more clearly diagnose deteriorated insulator in the string.
作者
孙瑞筱
胡玉耀
蒋兴良
咸日常
陈雨
Sun Ruixiao;Hu Yuyao;Jiang Xingliang;Xian Richang;Chen Yu(College of Electric and Electronic Engineering,Shandong University of Technology,Zibo 255000,China;Xuefeng Mountain Energy Equipment Safety National Observation and Research Station Chongqing University,Chongqing 400044,China;Shandong Huineng Electric Co.Ltd,Zibo 255000,China)
出处
《电工技术学报》
北大核心
2025年第11期3591-3603,共13页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(52477147)
山东省高等学校“青创团队计划”(2023KJ148)
山东省自然科学基金(ZR2023ME129)
湖南雪峰山能源装备安全国家野外科学观测研究站开放课题(N0RS-XFEES-23-04)资助项目。
关键词
A/B类污秽
劣化绝缘子
发热特征
红外成像
温升
Category A/B contamination
faulty insulator
heating characteristics
infrared imaging
temperature rise
