Electrical

OK, sorry, I'm being a curmudgeon. I see students trying to post their homework questions in here quite a bit and it bothers me. But I should have checked first to see that you don't appear to be a student, maybe an Instrumentation Tech who is being asked to do things other than your primary field of expertise?

Your question would encompass an entire semester's worth of study, each of those issues has myriad causes. but here are some GROSS generalizations:

1. Ground fault: A conductor is shorted to ground somewhere. Usually detected by monitoring all current carrying conductors in a system and if the return current doesn't match the supply current, there must be some going to ground.
2. Overload: More current is flowing into something than it is rated to carry.
3. unbalance: You would have to further define Current unbalance or Voltage unbalance, but they generally go hand in hand anyway. You have a 3 phase system, but because of the way loads are connected to them, the voltage/current is being altered to where the 3 values are not the same.
4. short circuit: A set of current carrying conductors is shorting between each other, i.e. Phase to Phase as opposed to Phase to Ground (Ground fault). But because some systems use a Neutral, which technically IS a current carrying conductor, a Phase to neutral fault is also called a Short Circuit even though eventually the current is going to ground.
5. earth fault: same as Ground fault, but that's how it is referred to in places outside of North America.