  This paper proposes a recursive method for integrity verification of measured
transformer currents, which is suitable for the modular development of
Hardware-In-the-Loop Digital Twins (HIL DTs). The Differential Equations (DEs)
describing transformer transients are relatively complex, requiring the use of
numerical DE solvers with small time steps. This implies that replicating
transformers with HIL DTs requires a continuous flow of accurate measurement
samples with a high sampling rate. The proposed method utilizes the Adaptive
Extended Kalman Filter to estimate the parameters of transformer currents which
can be non-sinusoidal during transients such as transformer energization. Then,
after evaluating the validity of estimations, the proposed method utilizes the
estimated parameters to reconstruct noiseless measurements with desirable
sampling rates. The performance of the proposed method is evaluated using
EMTP-RV for simulating transformers and Matlab for executing the proposed
method. The simulation results demonstrate that the method is able to
accurately estimate and closely track the current measurements.
