Stress Control for Polymeric Outdoor Insulators Using Nonlinear Resistive Field Grading Materials Operating Under Different Conditions
Stress Control for Polymeric Outdoor Insulators Using Nonlinear Resistive Field Grading Materials Operating Under Different Conditions
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使用不同条件下工作的非线性电阻场分级材料对聚合物户外绝缘子进行应力控制
DOI：
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发表时间：
2022
影响因子：
3.1
通讯作者：
G. N. Reddy
中科院分区：
文献类型：
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作者：
M;B. S. Reddy;G. N. Reddy
高压聚合物户外绝缘子两端配件附近的强电场增强有助于过早劣化和老化。非线性电阻场分级复合材料为应力控制和更具竞争力的产品提供了有希望的可能性，特别是随着功率密度和电压水平的增加。最近，基于氧化锌（ZnO）微压敏电阻器的新型非线性电阻性场分级材料（FGM）提供了使其能够在高压系统中使用的上级特性。此外，它们的开关参数可以在给定应用的广泛范围内定制。采用有限元法和COMSOL Multiphysics软件，讨论了基于ZnO微压敏电阻的非线性功能梯度材料在沿着230 kV户外聚合绝缘子应力控制中的有效性。研究了非线性功能梯度材料的电学特性，以获得沿绝缘体表面沿着的有效应力控制。基于在正常和非正常操作条件下与聚合物户外绝缘子相关的标准来确定FGM的导电性应该位于的${E}$ - $sigma $平面中的不同区域。提出了一个新的数学公式来表达场相关的FGM的电导率考虑在高场区的饱和效应。两种不同的绝缘子模型配备非线性电阻功能梯度材料，并在不同的操作条件下，交流和过电压进行评估。此外，在功能梯度材料内产生的电阻损耗和漏电流下的工频操作进行了评估。最后，我们研究了在高压直流输电系统中使用非线性功能梯度材料的可能性。
Strong electric field enhancements near both end fittings of the high-voltage polymeric outdoor insulator contribute to premature degradation and aging. Nonlinear resistive field grading composites offer a promising possibility to stress control and more competitive products, especially with the increasing power density and voltage levels. Recently, new nonlinear resistive field grading materials (FGMs) based on zinc oxide (ZnO) microvaristors offer superior characteristics that enable using them in high-voltage systems. Moreover, their switching parameters can be tailored across an extensive range for a given application. This article discusses the effectiveness of nonlinear FGMs based on ZnO microvaristors for stress control along a 230-kV polymeric outdoor insulator using the finite-element method and COMSOL Multiphysics. Investigations are conducted to appropriately find out the electrical properties of the nonlinear FGMs to get an effective stress control along the insulator surface. The different areas in the ${E}$ – $sigma $ plane where the conductivity of FGMs should lie are determined based on the criteria relevant to the polymeric outdoor insulator under normal and abnormal operating conditions. A new mathematical formula to express the field-dependent conductivity of FGMs is proposed to consider the saturation effect in high-field regions. Two different insulator models equipped with nonlinear resistive FGMs are presented and evaluated under different operating conditions, ac and overvoltages. In addition, the generated resistive loss within the FGMs and the leakage current under power frequency operation are evaluated. Finally, we studied the possibility of using nonlinear FGMs for polymeric outdoor insulators in HVDC systems.