Grounded Fuseless Cap bank calculations

[Uquresh1]

Have a solidly grounded fuseless capbank, and for protection settings I am following the IEEE standard guide C37.99-2000 . I have a double wye connection with 5 strings in each leg of the wye. So 5 in left wye for each phase, and 5 in the right Wye for each phase. I am getting a little confused on why the "Current in affected Wye(Iy)" is more than the "Current in the affected phase (Iph)".

for example Iy = 1.2 per unit and Iph is 1.1 per unit. Why? and also why the change from 1 per unit in Iy is double of that in Iph? (Iy changes 0.2 and Iph changes 0.1).

Thanks.

 

[7anoter4]

I cannot calculate the currents since I don't know what the number of parallel capacitors per string is and what the number of the blown capacitors is. But in any case Iph is more then Iy [as per example in fig.16]. You have to put G=0 and to calculate according to Table 2 and 3.