Design and application of double layer bowtie antenna and single layer bowtie antenna as UHF sensors for partial discharge detection

Abstract

Abstract The reliability of the power system cannot be achieved without good insulation quality of the high voltage apparatus. The Ultra-high frequency (UHF) method has been applied and proven to be accurate in detecting partial discharge (PD) signals emitted from the PD source in the form of electromagnetic waves. This paper discusses the design and application of double layer bowtie antenna and single layer bowtie antenna as UHF sensors for partial discharge detection in air insulation. The PD measurement results obtained by using the designed double layer bowtie antenna were compared with PD measurement results obtained by using the single layer bowtie antenna. The PD characteristics of induced EM waves detected by double layer bowtie antenna and single layer bowtie have been analysed. Based on the simulation results, the double layer bowtie antenna has a minimum return loss values of -31.54 dB and -33.43 dB, with corresponding resonance frequency values of 1.7 GHz and 2.7 GHz, with a total bandwidth of 602 MHz, and corresponding VSWR values of 1.04 and 1.05 while the measurement results by using Vector Network Analyser (VNA) shows that the designed double layer bowtie antenna has a minimum return loss of -20.2 dB, at a resonance frequency of 1.7 GHz, a bandwidth of 576 MHz and corresponding VSWR of 1.2. The single layer bowtie antenna has a bandwidth of 240 MHz, a minimum return loss of -24 dB, at a resonance frequency of 1.28 GHz, and a VSWR of 1.13 based on the simulation results while the single layer bowtie antenna has a bandwidth of 298 MHz, a minimum return loss of -23.32 dB, at a resonance frequency of 1.3 GHz, and a VSWR of 1.14 based on the measurement results by using VNA. The bowtie antennas were designed using the 3D-HFSS software with FR4-epoxy substrate type and later on were printed on the Printed Circuit Board (PCB). The PD measurement data were performed by using the applied voltage level of 7 kV. According to the antennas simulation results, antennas measurement results by VNA and PD measurement results, the double layer bowtie antenna has proven to be more sensitive than the single layer bowtie antenna.