Estimation of geoelectric field for validating geomagnetic disturbance modeling

Geomagnetic induced currents (GICs) cause half cycle saturation of transformers and consequently increase the harmonic currents and reactive power in the grid. This paper focuses on the GIC modeling as an important geomagnetic disturbance (GMD) mitigation program. A linear model is presented which relates the transformer GICs to the geoelectric fields based on power network topology and conductances. Using the transformer GIC measurements, three effective techniques are proposed for estimating geoelectric fields, namely the Least-squares (LS) estimator, the Ridge Regression (RR) Estimator and the Lease Absolute Value (LAV) one. The effectiveness of the three estimators under various noise scenarios is validated for a small systems and a larger test case through simulation results.