Grid-Induced Telluric Currents for Non-Contact Load Monitoring and Fault Detection

Grid-Induced ground currents occur when line-imbalances flow into the earth, creating a form of man-made telluric current. At the soil surface, a 2-dimensional, directional current density exists which follows the time varying load profile of the local power distribution system. When a fault occurs (either line-to-line or line-to-ground), a perturbation can be observed in the differential voltages measured in the soil, making grid-induced telluric currents a unique and mostly unexplored candidate for non-contact grid monitoring and fault detection. The directional nature of the induced telluric current provides information that can be used to localize a power-grid fault. Presented here is a non-invasive sensing technique that allows direct measurements of a substation’s load profile at a distance of 0.8 kilometers. Identification of the direction of the induced current in the soil is explored. A discussion on the sensor’s positional sensitivity is given.