Modified Vivaldi Antenna Applied to Detect Partial Discharge in Electrical Equipment Based on Ultra-High Frequency Method

The designed antenna in this paper is used for detecting the ultra-high frequency (UHF) signal of partial discharge (PD) radiated from electrical equipment at substations. This paper modified the conventional Vivaldi antenna (CVA) based on the tapered slot antenna theory. A tapered slot edge with resonant cavity structure is embedded on the edge of the CVA. The simulation and measured results show that impedance bandwidth of the modified Vivaldi antenna (MVA) is extended from 1.2~3GHz to 0.5~3GHz. Directivity of the MVA is improved without changing the phase center. Gain and sensitivity of the MVA are both improved, where the maximum gain value is 7.9dBi (2GHz) and the average sensitivity value is higher than 12mm. A test platform is constructed in laboratory to verify the effect of the MVA. The test results show that the MVA is appropriate for detecting UHF PD signal. The MVA has higher detection sensitivity compared with the CVA, the ridged TEM horn antenna and the spiral antenna. The impulse response characteristic of time domain signal received by MVA is better, which is helpful for further data processing. © 2017, The editorial office of Transaction of China Electrotechnical Society. All right reserved.