Ultra-high frequency sensors positioning on the power transformer to mitigate the negative effects on the partial discharge localization accuracy

This paper proposes a new method for improving the partial discharge (PD) localization accuracy by detecting the best places of ultra-high frequency (UHF) sensors on the power transformer tank. In this way, firstly, the critical sites inside the power transformer that can produce PD are determined. Then the sensors' positioning is done in such a way that if the PD happens at each point of these critical sites, the distance between the estimated PD location obtained by solving the time difference of arrival (TDOA) equations and the actual PD location is laid in an acceptable range. For this purpose, the TDOA equations are linearized around the critical PD coordinates as a matrix form A.X = B. The configuration of the sensor positions that minimizes the condition number of the matrix A is the best configuration. To evaluate the effectiveness of the proposed method, several simulations and evaluations are performed on a power transformer in the CST software. The obtained results and comparing them with the previous method and also conventional arbitrary sensors positioning confirm the effectiveness of this method. In the ultra-high frequency (UHF) technique, the partial discharge inside the power transformer can be localized by the hyperbolic equations. This method is sensitive to the time difference of arrival (TDOA) between the sensors because a small error in the TDOA vector may introduce a considerable localization error. This sensitivity depends on where the UHF sensors are installed on the transformer tank. By properly positioning the UHF sensors on the tank, this sensitivity is reduced. This paper presents a new method to find the best places on the transformer tank for installing the UHF sensors in such a way that the errors in the TDOA vector have the least effect on the localization accuracy.image