Experimental Study on the Propagation Characteristics of Electromagnetic Wave Signals in 1100 kV GIS Equipment with Different Structures

Partial discharge is the main manifestation of GIS before failure. Partial discharge pulses will generate high-frequency electromagnetic waves. The current electromagnetic wave detection sensor design is for GIS with voltage levels of 550 kV and below. The detection frequency band and sensor layout may not be applicable to 1100 kV GIS. This paper conducts insertion loss tests on the 1100 kV GIS equipment of the UHV Huangshi Substation under different structures such as linear, L-shaped, and T-shaped in engineering practice for long-distance busbars. It is obtained that with the increase of frequency, the attenuation of 200–2000 MHz signals decreases, and the higher the frequency, the smaller the attenuation. Within the frequency band of 200 M - 300 MHz, the average attenuation is 1.91 dB/m. Within the frequency band of 300–2000 MHz, the average attenuation is 1.49 dB/m. After propagating through an L-shaped structure, the electromagnetic wave signal attenuated by 51.95–55.82 dB. When passing through the T-shaped structure, the attenuation was 17.34–34.74 dB. The attenuation was greater than liner structure, much smaller than that of the L-shaped structure. The test results can guide the selection and layout of electromagnetic wave sensors for 1100 kV GIS equipment.