How current run in conductor by electrons
... but when current going to ground than all electrons going to ground as well.

No. If current is flowing out one end of a cable then current must be flowing in the other.

Then why there is no shortage of electrons in grid.

Because current flows in circuits which are closed loops. No circuit - no current.
Simple experiment: connect one end of a battery to ground with a multimeter on mA DC range.



simulate this circuit &ndash; Schematic created using CircuitLab
Figure 1. An open circuit. How much current do you think will flow?
Note: do not connect your multimeter in amps mode across the battery terminals. A high current will result and it may damage your meter.

From comments below the question:

Thanks for answer but as far I know ground is 0v. So ground can only take electrons but we can not take back electrons from ground.

Ground can accept or supply electric charge. If it couldn't then alternating current couldn't flow through it.