Design of dipole antenna model for partial discharge detection in GIS

Detecting Partial Discharge (PD) in Gas Insulated Switchgears (GIS) is the most effective method to assess the insulation condition. One of the popular method PD detection is Ultra-High-Frequency method (UHF-method). UHF antenna/sensors are the most important part of UHF method PD measurement. The sensor should be simple, small size, wideband, and small return loss. Many types of UHF antenna have been developed in bandwidth 300 MHz-3 GHz for detecting electromagnetic wave with ultra high frequency generated by partial discharge. Dipole antenna is one type of broadband antenna. This paper deals with design of dipole antenna as UHF sensor. An investigation on the effect of length and width of the sensor on the characteristics are carried out. Adding a stub as an attempt to achieve wider bandwidth resulting T antenna is also discussed. A three-dimension finite difference time domain (FDTD) simulation is applied to the antenna model and the results are confirmed by measurements with a network analyzer. The simulation and measurement results give a good agreement. Measurement of PD in GIS model tank is also examined using the developed dipole and T antenna sensors.