Line impedances for the power system shown in Figure 10.47
Chapter , Problem 10.21(choose chapter or problem)
Line impedances for the power system shown in Figure 10.47 are Z12 _ Z23 _ 3:0 _ j40:0 W, and Z24 _ 6:0 _ j80:0 W. Reach for the zone 3 B12 impedance relays is set for 100% of line 12 plus 120% of line 24. (a) For a bolted three-phase fault at bus 4, show that the apparent primary impedance seen by the B12 relays is Zapparent _ Z12 _ Z24 _ I32=I12_Z24 where I32=I12_ is the line 23 to line 12 fault current ratio. (b) If jI32=I12j > 0:20, does the B12 relay see the fault at bus 4? Note: This problem illustrates the infeed e_ect. Fault currents from line 23 can cause the zone 3 B12 relay to underreach. As such, remote backup of line 24 at B12 is ine_ective.
Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.
Becoming a subscriber
Or look for another answer