**This question ❓ is very important regarding your makaut semester examination**

**This question ❓ is made looking after your university decided MCQ based exam during the pandemic situation**

**"POWER SYSTEM -III "**

**Electrical engineering 4th year student and this question also comes in your compatitave examination like GATE, PSU, & Other gov. And private exam include your state gov. Examination **

**1.**What is the value of Inductive reactance in short transmission lines?

a) More at reciving end

b) More at sending end

**c) Uniformly distributed over entire length**

d) More in middle of sending end and reciving end

**2**.Regulation of short transmission lines depends:

a) Only on line resistance

b) Only on line inductance

c) Only on line capacitance

**d) On line inductance and line resistance**

**3.**What is the percentage voltage regulation of short transmission line if its sending end and reciving end voltages are 160 KV and 132 KV respectively?

a) 30 %

**b) 21.21 %**

c) 12.12 %

d) 38.22 %

Explanation: % Voltage Regulation = (Sending end voltage -Reciving end voltage) ÷ Reciving end voltage

= [( 160 – 132 ) × 100] ÷ 132

= 21.21 %.

**4.**A single phase transmission line is transmitting 1,100 KW power at 11 KV and at unity power fector. If it has a total resistance of 5 Ω, what is the efficiency of the transmission line?

a) 80 %

b) 89.65 %

**c) 97.24 %**

d) 99.54 %

Explanation: Efficiency (η) = Power delivered ÷ (Power Delivered + line losses)

Line current (I) = P/V

= (1100 × 1000/11000)

= 100 Amp.

Line losses = I2 R

= (100)2 5

= 50 KW

η = [11000/(11000+50)] × 100

= 99.54 %.

**5**. Voltage regulation of a transmission line should be ________

**a) Minimum**

b) Maximum

c) Greater than 50 %

d) Less than 50 %

**6**. Which of the following is correct operating voltage range for medium transmission lines.

a) More than 765 KV

b) More than 400 KV

**c) More than 20 KV**

d) More than 132 KV

Explanation: Transmission lines having length more than 80 Km and less than 200 Km, operating voltage between 20 KV and 100 KV fall in the category of medium transmission lines.

**7.**What is the value of the charging current flowing to earth in medium transmission line.

a) Very high

**b) Medium**

c) Negligible

d) No capacitance

**8.**Performance analysis of medium transmission line is done ________

a) By reactance diagram

b) By symmetrical component analysis method

c) By neglecting line inductance

**d) On per phase basis**

**9.**What is the value of shunt capacitance of medium transmission line?

a) Very high

**b) Medium**

c) Zero

d) Negligable

**10**. Series inductance and series resistance of medium transmission lines are taken as:

a) Distributed and Lumped

b) Lumped and Distributed

c) Distributed

**d) Lumped**

**11.**Length of long transmission line is more than ___________

a) 80 Km

b) 50 Km

c) 120 Km

**d) 200 Km**

**12**. Range of surge impedance for an overhead transmission line is ____________

a) 12 Ω – 144 Ω

b) 40 Ω – 60 Ω

**c) 400 Ω – 600 Ω**

d) 300 Ω – 900 Ω

13. Range of surge impedance for an underground cables is _____________

a) 12 Ω – 144 Ω

**b) 40 Ω – 60 Ω**

c) 400 Ω – 600 Ω

d) 300 Ω – 900 Ω

**14**. The voltage rating of long transmission line is _________

a) 20 KV to 100 KV

b) Upto 20 KV

**c) Above 100 KV**

d) 60 KV to 80 KV

**15**. What is the value of characteristics impedance for loss free transmission line?

**a) √(L/C)**

b) √(R/C)

c) √(LC)

d) √(C/L)

**16**. Ferranti effect is not a problem for ________

a) Long Transmission lines

b) Medium Transmission lines

**c) Short Transmission lines**

d) Transmission line having high

capacitance

**17**. What happens during the Ferranti effect?

a) Reciving end current becomes more than sending end current

**b) Reciving end voltage becomes more than sending end voltage**

c) Reciving end power becomes more than sending end power

d) Reciving end frequency becomes more than sending end frequency

**18**. A transmission line of 200 Km is supplying at 50Hz frequency. What is the percentage rise in voltage at reciving end?

a) 20%

b) 1.2%

**c) 2.19%**

d) 20.8%

Explanation: Percentage rise in voltage = (ω2 l2 10-8 )/18

Solving this % Vrise = {(2 × Ω × 50) × 2002 × 10-8}/18

= 2.19%.

**19.**What is the limit within which the consumer’s end terminal voltage should be maintained?

a) ± 9 %

b) ± 10 %

c) ± 5 %

**d) ± 6 %**

**20**. Which of the following equipment is not used for voltage control?

a) Tap changing transformer

**b) Induction generators**

c) Series compensators

d) Synchronous phase modifiers

**21**. What is the full form of AVR? This term is related to voltage control?

a) Automatic Voltage Rectifier

b) Actuated Voltage Rectifier

c) Automatic Voltage Rectifier

**d) Automatic Voltage Regulator**

**22.**In a synchronous generator for how much time subtransient period of symmetrical short circuit current lasts?

a) For 200 Cycles

b) For 500 Cycles

c) For 30 Cycles

**d) For 2 Cycles**

**23**. What is the phase current in phase Y and in phase B out of R-Y-B when sudden short circuit to all three phases occurs at no load? It is given that after fault current in phase R is equal (Vm Sin ωt)

a) Y = Vm Sin(ωt +60°) & B = VmSin(ωt +120°)

**b)Y=vmSin(ωt+120°)**

**&B=VmSin(ωt+240°)**

c) Y = Vm Sin(ωt +240°) & B = Vm Sin(ωt +120°)

d) Y = Vm Sin(ωt +90°) & B = Vm Sin(ωt -90°)

**24.**Which of the following reactance is eliminated first in synchronous generator just after the symmetrical fault?

a) Leakage reactance

**b) Damper winding reactance**

c) Armature winding reactance

d) Field winding reactance

**25**. The maximum power delivered to the load for short transmission line is at

a) β=α

b) β>α

**c) β=δ**

d) β>δ

**26.**For a given power system, its zero and maximum regulation will occur at the impedance angle of

**a) 45**

b) 90

c) 0

d) 60

**27**. The charging currents due to shunt admittance can be neglected for ______ transmission line?

**a) short**

b) long

c) medium

d) all of the mentioned

**28**. A three phase transformer has a name plate details of 30 MVA and voltage rating of 230Y kV/69∆ kV with a leakage reactance of 10% and the transformer connection via wye-delta. Taking a base of 230 kV on the high voltage side, turns ratio of the windings is

**a) 2**

b) 1.5

c) 6

d) 4

Explanation: n= VHV/VLV = (230/√3)/69=1.92 =2

**29**. A 200 bus power system has 160 PQ bus. For achieving a load flow solution by N-R in polar coordinates, the minimum number of simultaneous equation to be solved is ___________

**a) 359**

b) 329

c) 360

d) 320

Explanation: Total buses = 200

PQ buses = 160

PV buses = 200-160 = 40

Slack bus = 1

Total number of equation = (40-1)*1 + (160*2) = 359

**30**. A 400 V, 50 Hz three phase balanced source ripples to a star connected load whose rating is S(=300+j400) kVA. The rating of the delta connected capacitor bank needed to bring p.f. to 0.9 lagging is _______ KVAR.

**a) 254.7**

b) 25.4

c) 84.9

d) 284.5

Explanation: Qc = P[tanθ1 – tanθ2] =300[(4/3) – cos-10.9] = 254.72 kVAR.