Question

Q2-Fill in the blanks by correct words/figures. Answer only 7 point . . (1) An overcurrent relay having a current setting of 125% is connected to a supply circuit through a current transformer of ratio 400/5. The pick-up value will be (2) The pick-up value of a relay is 7-5 A and fault current in relay coil is 30A. Its plug-setting multiplier is (3) Back-up protection functions when (4) The minimum relay coil current at which the relay operates is called......... (5) A relay performs the function of .......... (6)Buchholz relay is installed between and conservator. (7) Buchholz relay is a ............ relay. (8) A distributor is designed from ............ considerations. (9) The point of minimum potential of a uniformly loaded distributor fed at both ends with equal voltages will occur at 10-In a transmission line, generalized constants are equal and .

Answer 1

0.2 1) Given Pick up current setting = 125 7. -1.25 CT Ratio = 400/5 value current Rated sece econdary current of CT xcurrent setting 5 AX 1.25 of - 6.25 A Puck up current = 6.25A 2) Pick value of reday = 7.5A, fault current = 30 A its plug setting multiplier is ? P.S.M = fault current in corelay Pick up current → 30 4 705 P.S.M=4

3) Back up protection functions when power system fault is not cleared abnormal fault is not detected in required time because of failure of the appropriate circuit breakers to trip or an 4) The minimum rebuy current at which the relay operates is called Pick-up current 5) A relay performs the function of → At high voltage applications, a detects the fault and supply information relay to the circuit function circuit breaker which performs interruption. the 67 the Buchholz relay is installed between main tank containing transformer oil and the conservator. 7) Buchholz relay is a gas detector relay 8) A distributor is designed from voltage drop considerations