1000kV输电线路绝缘子串的均压屏蔽技术

1 000 kV交流特高压输电线路电压较高,需要对绝缘子串进行均压和屏蔽以保证线路能安全稳定运行,为此,应用有限元法对1 000 kV交流特高压输电线路各种典型绝缘子串型的电压分布进行了计算。计算考虑了均压环的管径、环径和安装位置对绝缘子串电压分布的影响;进行了绝缘子串型的电压分布、电晕和无线电干扰等真型试验,并对有限元计算结果和试验结果进行了比较。结果表明,当均压环安装在高压侧第2片和3片绝缘子之间、均压环管径为120 mm时,均压效果较好;管径为120 mm的屏蔽环对高压侧金具具有良好的屏蔽作用,在要求的电压值下绝缘子串未产生可见电晕,无线电干扰值<60 dB,且屏蔽环可改善绝缘子串的电压分布;有限元计算结果和试验结果较为吻合,可以指导均压环和屏蔽环的设计。

Grading Rings and Shielding Rings of 1 000 kVAC Transmission Line Insulator Strings

In order to guarantee the safe operation of insulator strings and fittings of 1 000 kV AC transmission lines,grading rings and shielding rings should be installed on lines for its high voltage.Voltage distribution of 1 000 kV AC transmission line insulator strings were calculated with the FEM by considering the tube diameter,ring diameter and location of grading ring.Voltage distribution,corona and radio interference voltage of insulator strings were tested.It is shown that voltage distribution of insulator string is satisfactory when grading ring is located between the second insulator and third insulator near high voltage side and tube diameter is 120 mm.There is no corona on insulator strings and fittings at required voltage,and the RIV levels are less than 60 dB.Shielding rings can improve voltage distribution of insulator strings near high voltage side too.Comparison between calculation results and tested results shows that they are in agreement.