Research On Field Inspection Method Of GIS Built-in UHF Sensor

With the continuous development of condition based maintenance and smart grid technology,the installation of gas insulated metal enclosed switchgear(hereinafter referred to as GIS)is becoming more and more popular.However,there is no effective sensitivity and safety testing method when the built-in sensor is installed on the GIS.The layout of the sensor is random for the GIS manufacturers.It is difficult for the operation and maintenance units to verify whether the monitoring range of the sensor covers the whole GIS.After transportation,many problems such as the built-in sensor itself in discharge and gas leakage are often seen.In this case,the on-line monitoring system is more frequently misreported and missed,and can not meet the requirements of site use.On the basis of the GTEM chamber test sensor method,this paper proposes a method to test the sensitivity of the built-in sensor by injection of steep pulse to GIS.The equivalent verification of the local discharge and the amplitude of injection steep pulse voltage is carried out on the true GIS defect simulation platform.The voltage amplitude of the injection of steep pulse is clearly defined and the detection process is worked out.The mechanism of the overvoltage is analyzed by studying the structure principle of the built-in UHF sensor,and the safety test side is put forward.The method and overvoltage suppression measures provide technical support for the operation and maintenance unit to carry out the built-in UHF sensor test.Through the simulation of the propagation characteristics of the GIS UHF electromagnetic wave,the attenuation of various discontinuous parts of the electromagnetic wave in the GIS is studied,the comprehensive assessment technique principle and the economic principle are made,and the typical GIS interval is formulated.The sensor layout scheme provides technical support for GIS manufacturer to design sensor layout.The results of this paper will ensure the steady improvement of the intelligent GIS equipment.It is of great significance for the on-line monitoring of GIS partial discharge and the construction of the intelligent system of power grid inspection.