Analysis of Icing Characteristics and Structural Optimization Design of Catenary Cantilever Insulator

doi:10.11985/2023.04.037

Abstract

Abstract:

The present study aims to explore the icing characteristics of catenary cantilever insulator at extremely low temperatures. To begin with, the icing test is carried out in the artificial climate chamber to determine the icing morphology of the cantilever insulator. By taking into account the test results, a 1:1 three-dimensional model is then established to analyze how the local electric field distribution is affected by the length of the icicle and the hanging water droplets at the end of the icicle. Finally, the structure of insulator sheath is optimized. According to the analytical results, when the cantilever insulator is installed at a certain angle, there is an air gap arising between the small sheath icicle and the adjacent large sheath surface as well as between the large sheath icicles. The air gap acts as a strong electric field, with the rate of field strength distortion reaching 621%. After the air gap is eliminated, the large and small sheathes are connected, thus resulting in the partial failure of creepage distance in the insulator. When the ice layer on the surface of the sheath melts, the tip of the icicle tends to form a suspended droplet, causing distortion to the electric field in the surroundings. At this time, the rate of field intensity distortion as caused by the droplet can reach 4 977%. The sheath of an extraordinary shape can serve as an effective wall icicle bridge sheath to increase the spacing of air gap, thereby reducing the amount of icicle on the insulator around the place where electric field is distorted.

Key words: High-speed railway, cantilever insulator, icing characteristics, localized arc, structural optimization

CLC Number:

TM216

DING Siyu, MA Jianqiao, ZHANG Ruiqian, LIANG Mengfei, WU Jintong. Analysis of Icing Characteristics and Structural Optimization Design of Catenary Cantilever Insulator[J]. Journal of Electrical Engineering, 2023, 18(4): 349-360.

Figures/Tables 27

References 24

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类型	爬电距离 L/mm	U=90 kV U/L/(V/mm)	U=27.5 kV U/L/(V/mm)
表面洁净	1 600	56.25	17.19
8组伞裙边缘被桥接	1 216	74.01	22.62
变化百分比(%)	-24	31.58	31.59

材料	相对介电常数	电导率/(S/m)
冰棱、冰层	75	1×10^-10
外绝缘伞套	5	1×10⁻¹²
内绝缘芯棒	3	4×10⁻¹³
空气	1.01	5×10⁻¹⁵
水滴	81	3×10^-2
金具	1×10⁸	1.5×10⁷

对象	长度
8#(mm) 9#(mm)	20					30				50
8#(mm) 9#(mm)	0	20	30	50		0	30	50		0	50

冰棱长度/mm	E_max/(V/m)	E'/(V/m)	畸变率η(%)
20	4 639 500	111 071	4 077.06
30	4 726 920	129 144	3 560.19
50	5 743 260	113 116	4 977.32