Question

Power Transmission  

Question: 03 (5 Points) Varley loop test is used to find the position of an earth fault on a line of length 40km. The resistance per km of a sound cable is 28 12 and the resistance of a faulty cable is 30 2. The fixed resistor has resistance of 250 each. The fault is calculated to be 7km from the test end. To what value of resistance was the variable resistor set? (EI)

Answer 1

Faste Merm Speed Sound Cable fault Cable at balanced can Ret Rf-X X+S et - Ret R5 =+1 xts On PtQ = Ret Rfts xts o xts - X+= 9 Ret Rfts ) pto RETRpts 1X - ote) (Ret Rg4s) -s x=> 360) (98240 4.30X40 15) -5 ) -, *= 1160-ą o for 'l length fault wire has Rg resistana d length . . X resistan PH 40 km - (40x30 ) 7 km 2 7x 30 - 2102 € 210- 1160 -5/2 = S= S 950x2 1900 the value to which cavable resistanu to be set is