Single-Phase Transformer Harmonics Produced During Geomagnetic Disturbances: Theory, Modeling, and Monitoring

The main purpose of this paper is to provide a methodology to monitor harmonics produced by power transformers during geomagnetic disturbances. The advocated scheme leverages the existing infrastructure and is based on the embedded operating quantities of microprocessor-based differential protection relays. The characteristics of single-phase transformer magnetizing current are discussed. The second harmonic signature is a good indicator of half-cycle saturation and can be mapped into an effective geomagnetically induced current. The proposed scheme was tested in closed-loop using a real-time digital simulator and validated with field measurements.

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IEEE Transactions on Power Delivery  (Volume:30 ,  Issue: 3 )