工程科学与技术2024，Vol.56Issue(3)：259-268,10.DOI:10.12454/j.jsuese.202300823
多重雷击下线路避雷器氧化锌阀片的劣化特性试验
Experimental Study on Deterioration Characteristics of Line Arrester Zinc Oxide Valve Under Multiple Lightning Strikes
摘要
Abstract
Objective Multiple lightning strikes considerably accelerate the deterioration of zinc oxide valve plate,leading to a sharp decline in its electrical and thermal performance.The current national standard for testing lightning arresters considers only a single lightning strike and fails to account for the influence of multiple strikes.Hence,when a lightning arrester undergoes multiple strikes,it severely impacts the power grid.The extent of damage to the zinc oxide valve plate varies with different parameters of multiple lightning strikes.This study selects a valve plate from a leading manufacturer in Nanyang.This plate has a diameter of 42 mm,a height of 20 mm,a continuous operating voltage of 2.4 kV,a rated voltage of 3 kV,and a nominal current of 10 kA.This study examines the deterioration characteristics of the zinc oxide valve plate under various lightning strike scenarios. Methods Firstly,the study establishes a multi-lightning strike test research platform.Before testing,it places the zinc oxide valve plate in an in-cubator for 30 min to stabilize its temperature.Then,it measures the valve plate's initial direct current(DC).The test platform then conducts an impact test on the valve disc,with intervals between strikes set to 50 ms and using a standard 8/20 ms impact current waveform.An infrared thermal imager captures immediate temperature readings,including the highest,lowest,and specific point temperatures.Following the impacts,the valve disc's DC parameters,U1mA,I0.75U1mA,and the reference voltage U0.1mA through 0.1 mA,are measured using the static MOA-II arrester valve disc DC parameter tester.The impact aging characteristics of the valve plate are analyzed by the change of DC reference voltage U1mA and leakage current I0.75U1mA.Finally,by modifying the current amplitude and shock frequency of continuous lightning strikes,this research conducts further tests under five different conditions:once at the rated current,once at 1.5 times the rated current,four times the rated current,another at 1.5 times the rated current,and finally at 12 times the rated current.These tests assess the thermal aging characteristics and DC parameters of zinc oxide valve plates under different operational conditions,using the physical appearance and DC parameters of the valve plates to evaluate dam-age levels. Results and Discussions The analysis of the valve disc's DC parameters under different impact multiplicities showed that changes in impact mul-tiplicities significantly affect the valve disc's tolerance.As multiplicities increase,the disc exhibits decreased shock resistance and reduced toler-ance.The analysis of valve disc DC parameters under different impulse current amplitudes reveals that the variation law of valve disc DC para-meters is similar to those under nominal current conditions as the impulse current amplitude increases.U1mA demonstrates a pattern of gradual de-cline,followed by a more rapid decrease and a significant rise in leakage current growth rate.Temperature rise analysis of the valve disc under different operating conditions showed that the highest temperatures in the zinc oxide valve disc mainly occur around the outer ring.The study also explores the effects of multiple lightning strike parameters on valve disc performance and deterioration by analyzing the nonlinear coefficient and the causes of damage.The nonlinear coefficients across five operating conditions initially range from 16 to 20 and decrease as the number of shocks increases.Discussion of the damage caused under multiple lightning strike scenarios concludes that the deterioration of the zinc oxide valve disc results from substantial thermal stress and degradation of the grain boundary barrier height under conditions of single weight 1.5 times,4 weight 1.0 time,4 weight 1.5 times and 12 weight impact.The law of temperature distribution from high to low around the outer ring also pre-disposes this area to damage first.Under single shock and 1.0 time nominal current condition,the degradation of the zinc oxide valve plate primarily stems from a decrease in barrier height and asymmetric distortion of the Schottky barrier. Conclusions The electrical,thermal properties,and failure modes of zinc oxide valve plates under multiple lightning strikes are examined by modifying the strike parameters.The study draws the following conclusions:1)The DC reference voltage of zinc oxide valve plates exhibits a"down-steady-down"trend under different impact multiplications;The stable region of the single heavy operating condition is extended,and the higher the number of multiple lightning strikes increases,the more pronounced the downward trend.Specifically,the DC reference voltage in the 4-heavy condition shows a steep drop,and the leakage current in the 12-heavy condition experiences a sharp increase.2)Under the same multipli-city with varying impact amplitudes,the leakage current of the valve plate shows a consistent variation amplitude in the initial stages of impact.Once the leakage current exceeds 20 mA,its deterioration rate significantly rises.3)The pattern of change in the nonlinear coefficient of the valve plate post-multiple shocks is similar to that observed in the DC parameter.Corresponding to three different stages,increasing the impact multipli-city and current amplitude cause a rapid decline in the nonlinear coefficient,1.5 times the nominal current of the valve disc nonlinear coefficient from 15 to accelerate the deterioration.4)The deterioration in the valve disc due to a single shock and 1 times the nominal current is primarily due to the distortion of the double Schottky barrier.As the number of impacts and the current amplitude rise,the influence of thermal stress becomes more pronounced.Under conditions of 4-heavy and 1.5 times as well as 12-heavy tests,the thermal stress surpasses that at the point of valve plate failure,and the probability of bearing twice fP reaches more than 40%.These conditions lead to more severe failure modes of the valve plate,changing its typical failure form.关键词
氧化锌阀片/多重雷击/泄漏电流/非线性系数/热应力Key words
zinc oxide valve plate/multiple lightning strikes/leakage current/nonlinear coefficient/thermal stress分类
动力与电气工程引用本文复制引用
马御棠,束洪春,王东阳,朱梦梦,符安志,黄林..多重雷击下线路避雷器氧化锌阀片的劣化特性试验[J].工程科学与技术,2024,56(3):259-268,10.基金项目
云南省技术创新人才培训对象项目(202305AD160062) （202305AD160062）
云南省兴滇英才支持计划-产业创业人才 （）
国家自然科学基金重点基金项目(52337005) （52337005）
南方电网科技项目(YNKJXM20191243 （）
YNKJXM20220025) （）
