with stand capacity or short circuit current?

I would say probably yes..but you would need to consider the application and specifaction of the particular device. Read the specifications.

1. over load current = long term excess current in a circuit, but not a short circuit or ground (earth) fault
2. fault level = the amount of current flowing during a fault of any kind, but also sometimes use when describing the total amount of fault current available in a circuit, i.e. how much current will be capable of flowing to a fault if it happens, base on system delivery capacity, transformer impedances, conductor resistance etc. etc.
3. short circuit current = fault current if the fault is a short circuit
4. withstand (it's one word) capacity = the amount of fault current which a device can carry (withstand) without becoming critically damaged from the magnetic forces.
   

Don't forget that time is also a factor in each of these ratings. Withstand, for example is a given voltage (or current), waveform and magnitude for a defined time.

A practical example is something I'm doing now:

Upgrading a 30 year old switchboard for installation of a larger Diesel Generator on a vessel.

The bus bars can take the load, and the overload. The bus bars cannot take the short circuit current, and the bus bar bracing (withstand) cannot take the electromagnetic forces (EMF) during short circuit. Before the current overheats the bus bars, they will fly out of the switchboard due to very high EMF pulling them from their braces (mounting).

One complete 60 Hz cycle is approximately 16.6 milliseconds. Peak current will occur in approximately 4 milliseconds, one quarter of the sine wave. The fastest overcurrent relay I know of is half cycle, 4 milliseconds too late. Current limiting fast blow fuses can blow in 2-3 milliseconds, but we are not allowed a non-resettable interrupt device on this vessel.

Solution: Go to 20% sub-transient reactance generator with much lower short circuit current and add some bus bracing.

In an Electrical Distribution System,when there is a fault ,there will be excessive current flowing through various devices like,transformers,switch boards,cables,current transformers,switchgear etc.

In a system the maximum current would be during dead short circuit between phases or between phase and earth.

One has to find out(calculate) short circuit current that will flow in the system.

the devices selected should withstand this short circuit current for a period of 1 to 3 sec.

This is the real meaning of short circuit withstanding capacity of the device

no, it's not the same.

1. Overload current : the protective device is set to nominal current as rated on the nameplate, but equipment must be able to hold the current flow of 1.15 to 1.5 times of its nominal.

2. Fault level : Unit in MVA, it is 1.732xLine VoltagexShort Circuit Current

3. Short circuit current : you know it. Unit in kA

4. Withstand capacity : capable of holding the peak shortcircuit current usually in max. 3 seconds.

short ckt current along with time means within that time, that much current can be flow without damaging the conductor, is it not withstand capacity of conductor? again for fault level, it is the highest level of fault(what ever may be the fault) current which can be saifly pass within the time limit, again is it not similar to withstand capacity? if the time 0.1 or 0.3 sec means conductor should be disconnected in this time before reaching the temparature limite, time should be kept in mind for all those cases.