What components of the electrical grid are most vulnerable to geomagnetically induced currents (GICs)?

Answer

High-voltage transformers

The greatest vulnerability in the electrical infrastructure lies with the large, high-voltage transformers, as they are susceptible to extreme, transient currents flowing unevenly through long conductors.

What components of the electrical grid are most vulnerable to geomagnetically induced currents (GICs)?
deviceweatherphoneimpactsolar storm