Optimization of Antenna Array for Partial Discharge Positioning in Substation Based on Cramér-Rao Lower Bound

• Published in: 2021 10th International Conference on Power Science and Engineering (ICPSE) pp. 8 - 11
• Main Authors: Wendong, Guo, Bo, Niu, Feiyue, Ma, Guobin, Feng
• Format: Conference Proceeding
• Language: English
• Published: IEEE 21.10.2021
• Subjects: Antenna theory; Array optimization; Azimuth; Cramér-Rao lower bound; Directive antennas; Optimization; partial discharge; Partial discharges; Positioning; Substations; UHF antennas
• DOI: 10.1109/ICPSE53473.2021.9656866

Partial discharge is an important symbol of insulation defects. Partial discharge detection system based on UHF antenna array can realize partial discharge location in air-insulated substation. Using spatial spectrum estimation can reduce the antenna array and achieve high-precision positioning with smaller array size. This paper discusses the direction finding accuracy of different antenna arrays with the help of Cramér-Rao lower bound. Through theoretical derivation and numerical calculation, the influence of array structure on direction finding performance is studied, which provides guidance for optimizing antenna array. The results show that in order to achieve high direction finding accuracy, the offset B in the analytical expression of array factor q should be as large as possible, and the amplitude A and initial phase \gamma should be selected reasonably according to the application requirements. The farther a single burst deviates from the original equilibrium position, the more drastic the change of the Cramér-Rao lower bound with the variable azimuth angle, and the worse the comprehensive direction finding performance.