Study On Electric Field And Potential Distribution Of Composite Insulator With A Partial Micro-gap

The site operation experiences show that, due to molding, injection productiontemperature, thermal expansion and contraction characteristics of material, the sealingprocess and so on, are inevitable to make a micro-gap between the hardware, the mandreland the umbrella skirt sheath, partial discharge phenomena usually occur within themicro-gap, so as to destroy the insulation of composite insulator. This paper is modeled byusing the finite element software, modelling composite insulators with the existence of alocal micro-gap, in-depth study the effect of the overall intensity of electric field andpotential distribution of the different micro-gap size and the position, to find out the rulesof the conclusion.1) The FXBW4-110/100of the composite insulator of high voltage transmission linesare commonly used in this paper, then are modeled and subdived by ANSYS.2) All the programs are compiled respectively, the hardware of the maximum fieldstrength under different parameters are exported, then compare all the datas, find out therelationship between the maximum field strength and the micro-gap size.3) The field strength value along the umbrella skirt surface are recorded at thedifferent micro-gap size and location, and carries on the data generalization with theMatlab software, a large number of datas are analysized and processed by the excelspreadsheet tools,painting field intensity distribution curve and voltage distribution curve.4) On the comprehensive analysis and curve fitting, get a different micro-gap size andlocation corresponding to different field potential distribution.The main conclusions as following:1)The local micro-gap obviously impact the potential distribution of compositeinsulators,especially in the first skirt sheds on the high–end and low-end,and there isabnormality field strength distribution between the three skirt sheds around the mirco-gap,while there is little effective on other position.2)With increasing size of gap, the voltage that the gap bears is improvedimmediately,then the internal field strength also increased rapidly, so the internaldischarge in the micro-gap becomes possibly;3)When the position of the micro-gap is changed, where a gap located in the arcdistance of100mm,900mm,the field distortion is more serious,also affect the innerskirt sheds field strength distribution around the axis of the composite insulator. Through the above analysis, a proposal of production process of the compositeinsulators, try to avoid the formation of a local micro-gap, especially in the local near bothends of the fittings; on the other hand, provide the technical support for insulation faultdiagnosis of composite insulator.