The neutral point of a 11 kV three-phase generator was protected using circulating current system which was grounded thr
Posted: Wed Apr 27, 2022 5:51 pm
The neutral point of a 11 kV three-phase generator was protected
using circulating current system which was grounded through a
resistance of 8.47Ω. The protective relay was set to operate when
unbalanced current 2 A to flow in the pilot wire. If the secondary
rated current of CTs is 5 A, find the suitable CTs ratio to protect
60 % of stator phase winding due to the fault to earth (fault
impedance is zero). The stator winding impedance is negligible. If
85 % of the stator winding is to be protected, with the same
setting, determine the new value of the grounding resistance.
using circulating current system which was grounded through a
resistance of 8.47Ω. The protective relay was set to operate when
unbalanced current 2 A to flow in the pilot wire. If the secondary
rated current of CTs is 5 A, find the suitable CTs ratio to protect
60 % of stator phase winding due to the fault to earth (fault
impedance is zero). The stator winding impedance is negligible. If
85 % of the stator winding is to be protected, with the same
setting, determine the new value of the grounding resistance.