Y2K is a software problem. There is no relationship between them, other than if they occur at the same time, there are two failures, not one, to deal with. Unlike lightning strikes, which produce very short duration voltage and current changes, geomagnetically induced currents can last for hours. Such extended-duration induced currents can cause increased transformer heating, insulation breakdown and transformer failure. In addition, the voltage fluctuations can cause relays to trip and portions of the grid to collapse.
Solar storms induce disturbances in electrical conductors.
The amount of disturbance is dependent on the length of the conductor. Since the electrical grid consists of very long conductors, the grid may become noisy or unstable. The effect on the grid is difficult to predict, but these disturbances are reduced in shorter conductors and are not expected to have a significant direct impact on local plant equipment. Since that time, a number of ground current detectors have been installed in the Northeast as part of the Electric Power Research Institute's Sunburst Project. In addition, many utility companies now have emergency operating procedures for solar storms.