# In a power system with negligible resistance, the fault current at a point is 8.00 p.u. The series reactance to be included at the fault point to limit the short-circuit current to 5.00 p.u. is

1.  3.000 p.u

2.  0.200 p.u

3.  0.125 p.u

4.  0.075 p.u

4

3.000 p.u

Explanation :
No Explanation available for this question

# Zero sequence currents can flow from a line into a transformer bank if the windings are in

1.  Ground star/delta

2.  delta/star

3.  star/grounded star

4.  delta/delta

4

Ground star/delta

Explanation :
No Explanation available for this question

# When a line to ground fault occurs, the current in the phase is 100 A. The zero sequence current in this case will be

1.  Zero

2.  33.3 A

3.   66.6 A

4.  100 A

4

33.3 A

Explanation :
No Explanation available for this question

# Capacitance Voltage Transformer (CVT) is used to

1.  Improve the power factor of the transmission

2.  Reduce losses in a transmission line

3.  Connect instruments on the LT side

4.  Reduce the incidence of overvoltage surges on transmission lines

4

Improve the power factor of the transmission

Explanation :
No Explanation available for this question

# What is the positive sequence currents in a three phase system, when the original phasors at which are Ia = (12 + j 6), Ib = (12 – j 12), Ic = (-15 + j 10)

1.  14.8 Amp

2.  16.2 Amp

3.  18 Amp

4.  10.2 Amp

4

14.8 Amp

Explanation :
No Explanation available for this question

# The line currents in ampere in phases a, b and c respectively are (400 + j 100), (75 – j 600) and (-300 + j500) referred to the same reference vector. The negative sequence components of currents will be

1.  25 Amp

2.   100 Amp

3.  160 Amp

4.  149.9 Amp

4

149.9 Amp

Explanation :
No Explanation available for this question

# What is the percentage increases of busbar voltage required to compensate for the reactance drop, when the feeder having a reactance of 5% carries a full load current at a p.f 0.8 lagging

1.  5 %

2.  1.2 %

3.  1.8 %

4.  3 %

4

3 \%

Explanation :
No Explanation available for this question

# A small generating station has a busbar divided into three sections each section is connected to a tie bar with reactor each rated at 5 mVA, 0.1 p.u. reactance. A generator of 8 mVA, rating and 0.15 p.u. reactance is connected to each section of the busbar. The short circuit capacity of the breaker, if a 3- fault takes place on one of the sections of the busbar, will be

1.  78.73 mVA

2.  10.23 mVA

3.  90.8 mVA

4.  85.6 mVA

4

78.73 mVA

Explanation :
No Explanation available for this question

# A transformer is rated at 11 kV/0.4 kV, 500 kVa, 5% reactance. What is the short circuit MVA of the transformer when connected to an infinite bus

1.  20 MVA

2.  10 MVA

3.  15 MVA

4.  5 MVA

4

10 MVA

Explanation :
No Explanation available for this question

# The following sequence currents were recorded in a power system under a fault condition: I positive = j1.653 p.u. I negative = -j0.5 p.u I zero = -j1.153 p.u The fault is

1.  Line – ground

2.  3- phase

3.  line - line ground

4.  line – line

4