What is the most common effect of a Geomagnetic Disturbance on the power system?

• A. Increase static electricity
• B. Transformer cores becoming saturated
• C. Generator output varies
• D. Abnormal VAR direction

Answer: (B)

The most common effect of a geomagnetic disturbance on the power system is that transformer cores can become saturated. Geomagnetic disturbances, such as those caused by solar storms, can induce geomagnetically induced currents (GICs) in the Earth's magnetic field. When these GICs flow through transformers, they can cause the magnetic field within the transformer to distort. As a result, the core can become saturated, leading to a number of operational issues.

When transformer cores are saturated, it can result in increased losses, overheating, and even damage to the transformers. This condition can also impair the transformer’s ability to function properly, potentially leading to voltage instability and a reduction in the reliability of the power system. Therefore, the saturation of transformer cores is a significant and well-documented impact of geomagnetic disturbances on the electrical grid. Understanding this effect is crucial for system operators to implement appropriate measures for mitigating the risks associated with these disturbances.