Design of a Circularly-Polarized UHF Antenna for Partial Discharge Detection

Abstract

In this work, a circularly-polarized ultra-high frequency (UHF) partial discharge (PD) antenna is proposed to detect the PD in 0.6 GHz-1.7 GHz. The proposed PD antenna consists of an Archimedean spiral antenna, a balun, and a cavity. The Archimedean spiral antenna is embedded by FR-4 as substrate and superstrate for miniaturization. The microstrip-to-paired strips balun is designed to yield good performance in the return loss, insertion loss, and amplitude and phase imbalances which are of great necessity for low axial ratio. The cavity is employed to obtain unidirectional radiation patterns and prevent external signal interference. However, it is found that the originally-designed cavity-backed antenna does not work properly near 1.35 GHz due to resonance phenomena in the cavity. In this work, the cavity is modified to tackle this problem. The proposed UHF PD antenna is fabricated and measured and the results show that it provides good impedance matching, realized gain, radiation pattern, and circular polarization. INDEX TERMS Broadband antennas, partial discharges, UHF antennas.

Detection, Classification and Location of Sources of Partial Discharges Using the Radiometric Method: Trends, Challenges and Open Issues

“…In 2020, the authors in [50] developed an Archimedian spiral antenna for the PD detection in the frequency range of 600 MHz up to 1.7 GHz band. A balun was coupled to the antenna in order to perform the impedance matching between the antenna patch and the connection terminal (50 Ω), acting as an impedance transformer.…”

“…The built antenna presents results of measurement of reflection coefficient, radiation pattern and gain very close to the simulated and promising for the application in PD detection. However, the structure developed by the authors in [50] has not been subjected to practical tests of PD detection.…”

Effects of Dispersion and Multi-Path Propagation in Partial Discharges Location

“…To convert a time difference ∆τ into a distance, it is necessary to know the propagation velocity v p , as shown in (7), where L 2 is the estimated position of the PDs source measured from the cable far-end, and L is the cable length. Thus, the location error (LE) is calculated using (8).…”

“…The location techniques provide a time difference ∆τ that is converted to an estimation of the PD source location L 2 , resulting in LE, as written in (7) and (8), respectively.…”

Design of Archimedes Spiral Antenna to Optimize for Partial Discharge Detection of Inverter Fed Motor Insulation

“…It has been known that the ultra-high frequency (UHF) technique by using an antenna sensor is a potential approach for PD tests at impulsive voltages. This is because the UHF antenna can receive the high frequency electromagnetic energy generated by PD activities and the disturbance with lower frequency energy distribution can be removed efficiently by using high-pass filter [25][26][27]. However, almost all the antenna reported for PD tests under sinusoidal or DC voltages based on the conclusions that PD energy is mainly distributed within the frequency ranging from 0 GHz to 0.8 GHz [40].…”