I'm running an arc flash study on some medium voltage gear--and from the utility company I have their available short circuit from the utility side (~5.5kA). Yet when i run an arc flash study I'm getting 3phase fault currents Upwards of 10 million amps (I've tried to attatch a screenshot of my schematic below for reference). Now oddly enough when i run a short circuit study im getting much more reasonable numbers of fault current, ~5.3kA. Any idea why there might be such a discrepancy and what is causing it?

Thanks