电瓷绝缘子破损对整串场强电位分布的影响研究

Study of Field Strength and Potential Distribution of Porcelain Insulator String with Broken Insulators

由于电瓷绝缘子的脆性特性,在过电压或外界应力的作用下会使电瓷绝缘子的伞裙发生局部破损.伞裙的不同破损位置,以及不同的破损片数会对整串绝缘子的最大场强、均压环上的场强和伞裙的电压承担值产生不同的影响.本文通过有限元法对电瓷绝缘子串进行建模分析,设电瓷绝缘子串中存在破损伞裙,并通过改变伞裙破损的片数、伞裙破损存在的位置,探讨对整串绝缘子的最大场强以及均压环上场强、破损处伞裙场强以及单片伞裙承担的电压值影响.结果表明:单片或多片绝缘子破损时,会影响整串最大场强分布,破损位置处于高压端时,会进一步增加均压环上场强与第1片钢脚与水泥连接处最大场强值;破损位置处于中、低压端时,整串最大场强、均压环上最大场强相对偏小,多片破损时表现规律更为明显;高压端伞裙破损时,场强发生严重畸变,沿面伞裙电压分布变得更加不均匀,中、低压端破损影响相对较小,多片伞裙破损时,规律同单片一致.其仿真结果对场强电压的畸变提供理论性依据,对线路安全稳定运行有一定的指导性作用.

Due to the brittle characteristics of porcelain insulator,the over voltage or the external stress can make porcelain insulator umbrella skirt local damage.Different damage locations and different pieces of damage umbrella skirt will affect the maximum field strength of the insulator,the field intensity on equalizing ring and umbrella skirt voltage value in different ways.Analysis is carried out on the porcelain insulator string by the finite element method,by setting the number of damage umbrella skirts and changing different locations, the maximum field strength,equalizer ring field strength and potential distribution are studied.The result shows:One or more pieces damaged insulator,will affect the whole string of maximum field strength distribution;when the damage insulator is located in a high voltage side,it will make a more strong incensement of the equalizing ring field strength and the maximum field strength;when it is located in the medium and low voltage side,the values are relatively small;and the rule is more obvious with more damage insulators.The serious distortion field and more nonuniform potential distribution will be happened when damage insulators are located at high voltage side;but damage insulators are located in the medium and low voltage side,the effect is smaller.The simulation results provide a theoretical basis for field strength and potential distortion and have certain guiding effect for the grid's safety and stable operation.