“L”形测试截面下GIS绝缘间隙UHF信号传播特性

UHF Signal Propagation Characteristics of GIS Insulation Gap Under“L Shaped”Test Section

当采用特高频UHF(ultra high frequency)检测技术进行局部放电监测时,基本均假定GIS具有良好的同轴波导射频传播特性,并不能完全反应实际GIS运行情况。为了掌握实际复杂GIS形状下的UHF信号传播特性,文中设计“L”形测试截面以及现场实际GIS的“П”截面,并首先进行实验测试,分析“L”形截面对UHF信号传播特性的影响,但只能得到GIS绝缘间隙中局部位置(传感器位置)的信号强度;为此,文中建立了“L”形有限元模型FEM(finite element model),并将FEM分析结果与测试结果进行对比,证明了该有限元模型的正确性,以此为基础,可分析得到整个GIS绝缘间隙的UHF信号传播特性。结果表明,所提实验室“L”形截面测试结果和有限元模型能够真实反应实际情况,准确性高。

When ultra high frequency(UHF)detection technology is used for PD monitoring,it is generally assumed that GIS has good coaxial wave guide radial frequency propagation characteristics which,however,can not fully reflect the actual operation of GIS.In order to master the propagation characteristics of UHF signal under the actual complex GIS shape,the“L shaped”test section and the“П”section of the actual GIS are designed in this paper,and the experimental test is carried out firstly.The influence of the“L shaped”section on the propagation characteristics of UHF signal is analyzed.But this method can only obtain the signal strength of the partial position(sensor position)in the GIS insulation gap.Therefore,the finite element model(FEM)of the“L shaped”test section and the correctness of the finite element model is proved by comparing the FEM analysis result and the test result.Based on this,the UHF signal propagation characteristics of the whole GIS insulation gap can be analyzed and obtained.The results show that the“L shaped”section test result proposed in the test laboratory and the finite element model can truly reflect the actual situation with high accuracy.