CAJ | 학술논문

上行先导是分析雷电绕击输电线路的关键因素之一,由于雷电放电的随机性,鲜有输电线路上行先导的直接影像资料,因而上行先导是否存在是电力系统防雷研究的一个热点。现有的上行先导仿真计算模型主要由棒-板及热力学的结论间接推导所得,缺乏实际输电线路的实验依据。在昆明国家特高压实验基地对输电线路上行先导起始及其发展特性开展了模拟试验研究,经过仿真分析,设计并采用5～8m的板棒-线间隙进行模拟试验,施加最高达3.6MV、200/2 000μs波前的冲击电压,利用最高拍摄速度为106帧/s的高速摄像机对放电过程的放电形态进行观测,利用3dB带宽范围为0～6.5MHz的同轴分流器进行了电流测量。通过500余次试验及其结果分析,发现在该试验条件下,导线和地线上明显有上行先导产生,其发展速度约为1.2～3cm/μs,与正极性操作波下棒-板间隙放电的先导速度基本一致。仿真分析发现,大多数自然雷情况下,输电线路临界半径处场强高于上行先导起始场强的时间比该文试验工况中更长,因此推断自然雷击输电线的过程中上行先导是很有可能存在的。
상행선도시분석뇌전요격수전선로적관건인소지일,유우뇌전방전적수궤성,선유수전선로상행선도적직접영상자료,인이상행선도시부존재시전력계통방뢰연구적일개열점。현유적상행선도방진계산모형주요유봉-판급열역학적결론간접추도소득,결핍실제수전선로적실험의거。재곤명국가특고압실험기지대수전선로상행선도기시급기발전특성개전료모의시험연구,경과방진분석,설계병채용5～8m적판봉-선간극진행모의시험,시가최고체3.6MV、200/2 000μs파전적충격전압,이용최고박섭속도위106정/s적고속섭상궤대방전과정적방전형태진행관측,이용3dB대관범위위0～6.5MHz적동축분류기진행료전류측량。통과500여차시험급기결과분석,발현재해시험조건하,도선화지선상명현유상행선도산생,기발전속도약위1.2～3cm/μs,여정겁성조작파하봉-판간극방전적선도속도기본일치。방진분석발현,대다수자연뢰정황하,수전선로림계반경처장강고우상행선도기시장강적시간비해문시험공황중경장,인차추단자연뢰격수전선적과정중상행선도시흔유가능존재적。
Upward leader is one of the key factors for analyzing the shielding failure of lightning,but a number of questions remain to be unanswered because it is difficult to observe the upward leader from transmission lines.In order to research whether the upward leader can incept from the transmission lines,it is necessary to study the characteristics of upward leader.Therefore,models of upward leader are established to calculate the rate of shielding failure by the breakdown voltage of rod-plane gap or theory of thermodynamics,but it is proved that these models are not completely suitable for analyzing the shielding failure of lightning.We presented results from the ultra high voltage laboratory in Kunming.Measurements were conducted in a rod-conductor gap of 5～8min length under maximum voltage of 3.6MV,200/2 000μs impulses,discharge was observed with high speed camera,the current was measured using a current shunt with frequency response of 0～6.5 MHz,and upward leader was observed in the process of discharge.The velocity of upward leader is found to be 1.2～3cm/μs,which is in accordance with the velocity of leader observed in rod-plane gap discharge under positive impulse.The duration of field strength when critical radius of conductors exceeds the critical value is longer than that in the experimental conditions,so the existence of upward leader in the process of shielding failure of lightning is reasonable.