The output is by channel, or the port of the controller into which the shelf is connected. Then, the output is by shelf ID.
So - in the first section, channel 1a, shelf ID 1. Within that output, about the middle, is the line "Power Supply installed element list: 1, 2, 3, 4; with error: 1, 3" That indicates the shelf has four power supplies installed, and two of them (positions 1 and 3) have failed.
You have similar lines in the other sections - the other two shelves indicated only have two power supplies each, and power supply 1 has failed on both.
Interestingly, assuming good practice was followed in connecting A/B side power and such, I'd suspect a PDU or similar power failure issue within your rack(s). The failures are all on PSU's installed on the same sides of the shelf. This assumes that the PSU's on one side of the shelf are all plugged into the same power feed circuit in a dual circuit setup.
My thought on PDU issue also assumes that these errors occured at essentially the same time. If these errors have been building over time, you likely have a larger set of issues to deal with.