How to calculate the power reserve for overvoltage, undervoltage, and overcurrent protection in PC power supplies?

What are overvoltage protection (OVP), undervoltage protection (UVP), and overcurrent protection (OCP) in PC power supplies? Every PC power supply is backed by advanced protection mechanisms that protect the PSU and costly PC components from damage. The OVP, UVP, and OCP are part of this set.