500kV站用绝缘子串均压环优化设计

Optimization of Shielding Ring of Insulator String in 500 kV Substation

为改善500 kV港城变电站电晕放电现象,根据其绝缘子串布置情况,利用有限元计算方法,在ANSYS中建立悬垂串与双联串仿真模型,研究均压环不同结构参数对绝缘子串电压、电场分布的影响,得到最优均压环结构参数。仿真结果表明,500 kV悬垂串均压环最佳结构参数为:罩深230 mm、环径660 mm、管径70 mm,均压环表面最大场强峰值可降至14.5 kV/cm;双联串均压环最佳结构参数为:屏蔽绝缘子片数3、管径100 mm、与绝缘子距离90 mm,均压环表面最大场强峰值可降至14.7 kV/cm。计算结果证明,优化后的均压环明显改善绝缘子串电压分布,降低了单片绝缘子承担的最大电压,并使均压环表面最大场强峰值低于20 kV/cm。

To restrain the corona discharge phenomena in Gangcheng 500 kV substation, according to the actual circumstance of the substation, simulation models of suspension insulator string and double tension insulator string are established in ANSYS by using finite element method. The influences of different structural parameters of shielding rings on electric field and voltage distribution along an insulator string are calculated to achieve the optimum structural parameters of a shielding ring. Simulation results show that the optimum structural parameters of shielding ring are： 230 mm in cover depth, 660 mm in diameter, and 70 mm in caliber for the 500 kV suspension insulator string, which can reduce the maximum peak value of electric field strength on the shielding ring to 14.5 kV/cm; and 3 in number of ring shields, 100 mm in caliber, and 90 mm in distance between shielding ring and insulator for the double tension insulator string, which can reduce the maximum peak value of electric field strength on the shielding ring to 14.7 kV/cm. Calculation results show that the optimized shielding ring obviously improves the voltage distributions along the suspension insulator string and double tension insulator string, reduces the maximum voltage on single insulator, and makes the maximum peak value of electric field strength on shielding ring lower than 20 kV/cm.