1
GATE EE 2008
+2
-0.6
Voltage phasors at the two terminals of a transmission line of length $$70$$ km have a magnitude of $$1.0$$ per unit but are $$180$$ degrees out of phase. Assuming that the maximum load current in the line is $$1/5$$th of minimum $$3$$-phase fault current. Which one of the following transmission line protection schemes will NOT pick up for this condition?
A
Distance protection using mho relays with zone-$$1$$ set to $$80$$% of the line impedance.
B
Directional over current protection set to pick up at $$1.25$$ times the maximum load current
C
Pilot relaying system with directional comparison scheme
D
Pilot relaying system with segregated phase comparison scheme.
2
GATE EE 2003
+2
-0.6
A list of relays and the power system components protected by the relays are given in List-$${\rm I}$$ and List-$${\rm II}$$ respectively. Choose the correct match from the four choices given below

List-$${\rm I}$$
$$A.$$ Distance relay
$$B.$$ Under frequency relay
$$C.$$ Differential relay
$$D.$$ Buchholz relay

List-$${\rm II}$$
$$1.$$ Transformers
$$2.$$ Turbines
$$3.$$ Busbars
$$4.$$ Shunt capacitors
$$5.$$ Alternators
$$6.$$ Transmission lines

A
$$A = 6,\,B = 5,\,C = 3,\,D = 1$$
B
$$A = 4,\,B = 3,\,C = 2,\,D = 1$$
C
$$A = 5,\,B = 2,\,C = 1,\,D = 6$$
D
$$A = 6,\,B = 4,\,C = 5,\,D = 3$$
3
GATE EE 2000
+2
-0.6
The plug setting of a negative sequence relay is $$0.2$$ $$A.$$ The current transformer ratio is $$5:1$$. The minimum value of line to line fault current for the operation of the relay is
A
$$1A$$
B
$${1 \over {1.732}}A$$
C
$$1.732$$ $$A$$
D
$${{0.2} \over {1.732}}A$$
4
GATE EE 1998
+2
-0.6
The neutral of $$10$$ $$MVA,$$ $$11$$ $$kV$$ alternator is earthed through a resistance of $$5$$ ohms. The earth fault relay is set to operate at $$0.75$$ $$A.$$ The $$CT's$$ have a ratio of $$1000/5.$$ What percentage of the alternator winding is protected?
A
$$85$$%
B
$$88.2$$%
C
$$15$$%
D
$$11.8$$%
EXAM MAP
Medical
NEET