1
GATE EE 1999
MCQ (Single Correct Answer)
+1
-0.3
A $$PWM$$ switching scheme is used with a three phase inverter to
A
Reduce the total harmonic distortion with modest filtering
B
Minimize the load on the $$DC$$ side
C
Increase the life of the batteries
D
Reduce low order harmonics and increase high order harmonics
2
GATE EE 1999
Subjective
+5
-0
A three phase diode bridge is used to provide rectified output from a $$400V,$$ $$50$$ $$Hz,$$ $$3$$- phase supply to a $$R$$ $$-$$ $$L$$ load with $$10\,\,\Omega $$ resistance and $$300$$ $$mH$$ inductance.
Determine the
(a)$$DC$$ level of the output voltage
(b) $$RMS$$ value of the diode current
(c) $$RMS$$ value of the source current, and
(d) Apparent power drawn from the mains
3
GATE EE 1999
MCQ (Single Correct Answer)
+2
-0.6
An industrial consumer has a daily load pattern of $$2000$$ $$kW$$, $$0.8$$ lag for $$12$$ Hrs. and $$1000$$ $$kW$$ $$UPF$$ for $$12$$ Hrs. The load factor is
A
$$0.5$$
B
$$0.75$$
C
$$0.6$$
D
$$2.0$$
4
GATE EE 1999
Subjective
+5
-0
A 66 kV, 3-phase, 50 Hz, 150 km long overhead transmission line is open circuited at the receiving end. Each conductor has a resistance of 0.25$$\Omega $$/km, an inductive reactance of 0.5$$\Omega $$/km and a capacitive admittance to neutral of 0.04 $$ \times $$ 10-4 S/km.

(a) Draw the nominal π-equivalent circuit and indicate the value of each parameter.
(b) Calculate the receiving end voltage if the sending end voltage is 66 kV.