Determination of Split factor/ Division factor

That section of the IEEE standard 665-1995 has a reference to "[B11]", which points you to an IEEE Transactions paper in Section 6, the Bibliography. Look up that reference, and it will explain how to graphically determine the fault current and what is the "split" between how much of it will flow in the ground and how much will take other paths back to system neutral point.

Unless you have guidance from someone who has dealt with it before, you will find this a tedious and difficult task. Common rule of thumb used in utility system ground grid evaluation is that 60% of the fault current will flow in the ground grid, and the rest will flow in other paths (shield wires, other paths to neutral). This has been empirically shown to be a fair representation, although I don't have a direct reference to point you to.

thanks for the reply sir