A 3-phase transformer rated for 33 kV/11 kV is connected in delta/star as shown in figure.
The current transformers (CTs) on low and high voltage sides have a ratio of 500/5. Find
the currents i1 and i2, if the fault current is 300A as shown in figure.
A nuclear power station of 500 MW capacity is located at 300 km away from a load center. Select the most suitable power evacuation transmission configuration among the following options
A.
B.
C.
D.
Answer : Option AExplaination / Solution: No Explaination.
A load center of 120MW derives power from two power stations connected by 220kV transmission lines of 25km and 75km as shown in the figure below. The three generators G1,G2 and G3 are of 100MW capacity each and have identical fuel cost characteristics. The minimum loss generation schedule for supplying the 120 MW load is
A.
B.
C.
D.
Answer : Option AExplaination / Solution:
Loss α p2 ; Loss α length
For checking all options only option A gives less losses.
In a 100 bus power system, there are 10 generators. In a particular iteration of Newton Raphson load flow technique (in polar coordinates), two of the PV buses are converted to PQ type. In this iteration,
A. the number of unknown voltage angles increases by two and the number of unknown voltage magnitudes increases by two.
B. the number of unknown voltage angles remains unchanged and the number of unknown voltage magnitudes increases by two.
C. the number of unknown voltage angles increases by two and the number of unknown voltage magnitudes decreases by two.
D. the number of unknown voltage angles remains unchanged and the number of unknown voltage magnitudes decreases by two.
A solar energy installation utilize a three – phase bridge converter to feed energy into power system through a transformer of 400V/400 V, as shown below.
The energy is collected in a bank of 400 V battery and is connected to converter
through a large filter choke of resistance 10Ω.
The maximum current through the battery will be
A. 14 A
B. 40 A
C. 80 A
D. 94 A
Answer : Option AExplaination / Solution:
Workspace
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Total Question :
Score Mark :
Mark for Correct Answer : 1
Mark for Wrong Answer : -0.33
Mark for Left Answer : 0