RSSI-Based Direction of Arrival Estimation Using Maximum Likelihood Estimator and UHF Antenna Array

The localization of partial discharge (PD) using ultra-high frequency (UHF) technology is studied in air-insulated substations for early warning of power equipment. The traditional UHF PD localization system is usually based on algorithms utilizing the time-difference of electromagnetic wave signal to perform localization. However, those systems have oversize problem and requires high sampling rate and high time synchronization rate to maintain high estimation accuracy. To address this challenge, this paper proposed a received signal strength indicator (RSSI) based PD localization method. This paper researches on the feasibility and accuracy of PD direction of arrival (DoA) using power of UHF RSSI signal. After achieving the UHF antenna power pattern in the experiment, the paper proposes a method using maximum likelihood estimator to handle PD direction of arrival estimation and obtain the orientation results. We conduct a field test and the experiment results show the average error of direction of arrival is less than 6°. The results verify the effectiveness of the proposed PD localization system.