Geomagnetic Induced Current Measurement in Hybrid PV-Wind System Transformers

Abstract

Geo magnetically induced currents (GICs) can cause saturation of the magnetic core of transformers in a power system. This saturation can conduce to generating harmonic currents, voltage-control problems and overheating of the transformer internal components, leading to gas relay alarm/operation and possible damage. In this work, GICs effects have been analyzed on hybrid PV-wind system transformers. The system implemented through using Power System Computer Aided Design (PSCAD/EMTDC) platform and made up of 2.1 MW wind farm, 2 MW solar photovoltaic (PV) farm, power storage system and load. Then the system is integrated with 33 kV grids through a 480V AC bus and step-up wye/delta transformer. In addition, Pi-section has been used between different parts of the system. The GIC is modeled as a controlled DC voltage source and inserted into the system through a neutral point of a wind turbine (WT) transformer. The simulation results of reactive power, voltage and current waveforms, and non-linear behavior due to asymmetric saturation of the magnetic core in the transformer due to 100 A GIC current injections are obtained. Moreover, different GIC blocking devices have been applied to mitigate or eliminate the flow of GIC to the system.