Digital Twin of Distribution Power Transformer for Real-Time Monitoring of Medium Voltage from Low Voltage Measurements

Abstract: Real-time monitoring of distribution systems has be-come necessary, due to the deregulation of electricity markets and the wide deployment of distributed energy resources. To monitor voltage and current at sub-cycle detail, requires, typically, major investment undertaking and disruptions to the operation of the grid. In this work, measurements of the low voltage (LV) side of distribution transformers (T/F) are used to calculate in real time the waveforms of their medium voltage (MV) sides, based on a mathematical model of said T/F. This model is, essentially, the dig-ital twin of the MV side of the T/F. The method calculates T/F MV waveforms of voltage and current, and active and reactive power as accurately as an instrument T/F, captures all harmonics con-tent, is unaffected by asymmetrical loading and identifies most sys-tem faults on the MV side of the T/F. The digital twin method en-ables monitoring of distribution T/F that avoids MV instrumenta-tion, does not suffer in accuracy and may be readily deployable. Field data from an actual MV-LV T/F, agree with simulation re-sults showcasing the efficacy of the digital twin method.