1
GATE EE 2006
MCQ (Single Correct Answer)
+1
-0.3
An HVDC link consists of rectifier, inverter transmission line and other equipments. Which one of the following is true for this link?
A
The transmission line produce/supplies reactive power
B
The rectifier consumes reactive power and the inverter supplies reactive power from/to the respective connected consumes
C
Rextifier supplies reactive power and the inverted consumes reactive power to/from the respective connected AC systems
D
Both the converters (rectifier and inverter) consume reactive power from the respective connected AC systems.
2
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.67
Three identical star connected resistors of $$1.0$$ $$p.u$$ are connected to an unbalanced $$3$$ phase supply. The load neutral is isolated. The symmetrical components of the line voltages in $$p.u.$$ calculations are with the respective base values, the phase to neutral sequence voltages are
A
$${V_{an1}} = X\angle \left( {{\theta _1} + {{30}^0}} \right),\,\,{V_{an2}} = Y\angle \left( {{\theta _2} - {{30}^0}} \right)$$
B
$${V_{an1}} = X\angle \left( {{\theta _1} - {{30}^0}} \right),\,\,{V_{an2}} = Y\angle \left( {{\theta _2} + {{30}^0}} \right)$$
C
$${V_{an1}} = {1 \over {\sqrt 3 }}X\angle \left( {{\theta _1} - {{30}^0}} \right),\,\,{V_{an2}} = {1 \over {\sqrt 3 }}Y\angle \left( {{\theta _2} - {{30}^0}} \right)$$
D
$${V_{an1}} = {1 \over {\sqrt 3 }}X\angle \left( {{\theta _1} - {{60}^0}} \right),\,\,{V_{an2}} = {1 \over {\sqrt 3 }}Y\angle \left( {{\theta _2} - {{60}^0}} \right)$$
3
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
For a power system the admittance and impedance matrices for the fault studies are as follows. $$$\eqalign{ & {Y_{bus}} = \left[ {\matrix{ { - j8.75} & {j1.25} & {j2.50} \cr {j1.25} & { - j6.25} & {j2.50} \cr {j2.50} & {j2.50} & { - j5.00} \cr } } \right] \cr & {Z_{bus}} = \left[ {\matrix{ {j0.16} & {j0.08} & {j0.12} \cr {j0.08} & {j0.24} & {j0.16} \cr {j0.12} & {j0.16} & {j0.34} \cr } } \right] \cr} $$$

The pre-fault voltages are $$1.0$$ $$p.u.$$ at all the buses. The system was unloaded prior to the fault. A solid $$3$$ phase fault takes place at bus $$2.$$

The per unit fault feeds from generators connected to buses $$1$$ and $$2$$ respectively are

A
$$1.20, 2.51$$
B
$$1.55, 2.61$$
C
$$1.66, 2.50$$
D
$$5.00,2.50$$
4
GATE EE 2006
MCQ (Single Correct Answer)
+1
-0.3
A $$400$$ V, $$50$$ Hz, three phase balanced source supplies power to a star connected load whose rating is $$12\sqrt 3 $$ kVA, $$0.8$$ pf(lag). The rating (in kVAR) of the delta connected (capacitive) reactive power bank neccessary to bring the pf to unity is
A
$$28.78$$
B
$$21.60$$
C
$$16.60$$
D
$$12.47$$