Repetitive Learning Control for the Correction of Wound-Type Potential Transformer Measurement Errors: Sensitivity Analysis

Successful implementation of a transmission level harmonic measurement system requires accurate and reliable measurement of harmonic voltages and currents. Existing substation instrument transformers are designed for harmonic-free 60 Hz measurements. Hence, their use to measure harmonics leads to the introduction of resonance as well as saturation errors in the measurements. An on-line error correction method to correct for wound-type potential transformer measurement errors has been proposed in previous publications. The error correction was formulated as an output tracking problem where the distorted measurements were used along with the experimentally developed transformer model to reconstruct the transformer input. The scope of this paper is to develop a sensitivity analysis for the error correction method with respect to the transformer parameters. Results of this analysis indicate that the sensitivity of the method with respect to the transformer parameters is quite low. Index Terms--Transformer, error, correction, sensitivity.