Year 2023

Week # 2 Quiz 4

Q1. A 300 MVA alternator operated at no load at frequency of 50 Hz, it has inertia constant of 4 MW-sec/MVA and governing system has a time delay of 0.5 sec. If the load of 40 MW is suddenly applied then find the frequency deviation during this time.

Q2. An industrial consumer has a connected load of 10 machines, each having a rating of 10 kW. The maximum demand is 80 kW. On an average each machine works for 8 hrs a day for 300 working days in a year. The tariff is Rs. 10000 + Rs. 800 per kW of maximum demand + Rs. 1.15 per kWh of energy consumed. The annual bill of the consumer will be:

Q3. Consider that the light goes from medium A to medium B at angle of incidence of \(40^\circ\) and the angle of refraction is \(30^\circ\). Then,

Q4. A transmission line has a surge impedance of \(400 \Omega\) is connected with the cable having surge impedance of \(40 \Omega\), a surge magnitude of \(110 kV\) is travelling from the transmission line towards the cable. Find the transmitted voltage.

Q5. For the bus admittance matrix \(Y_{bus}\) of a \(4\)-bus system given in per unit, the buses having shunt elements are
\(Y_{bus} = j\begin{bmatrix}-7 & 2 & 3 & 0 \\2 & -12 & 4 & 2.5 \\3 & 4 & -9 & 2 \\0 & 2.5 & 2 & -4.5 \end{bmatrix}\)

Q6. Consider two buses is connected by an impedance of \((0+j5)\Omega\) The bus 1 voltage is \(100 \angle 30 ^\circ\) V, and bus 2 voltage is \(100 \angle0 ^\circ\) V. The real and reactive power supplied by bus 1, respectively are (Consider power flowing from bus 1 to 2 as positive)

Q7. Two units in a thermal plant are operating with a minimum load of 50 MW each. Their incremental costs are :
\(IC_1 = 16 + 0.08 P_1 \: RS/MWh\)
\(IC_2 = 12 + 0.1 P_2 \: Rs/MWh\)
For most economic operation, how the total load of 130 MW will be shared?

Q8. The current flowing to a balanced delta connected load through line 'a' is 15 A when the conductor of line 'b' is open. With the current in line 'a' as reference, compute the symmetrical components of the line currents. Assume the phase sequence of 'abc'.

Q9. A loss less transmission line is operating under no load condition. It has ABCD parameters \(B = 100 \angle 90^\circ\) has a phase shift of \(0.3 \:rad\), what value of shunt reactor is required for compensation of Ferranti effect?

Q10. A Power system consists of 300 buses out of which 20 buses are generator bus, 25 buses are ones with reactive power support and 15 buses are the ones with fixed shunt capacitors. All the other buses are load buses. It is proposed to perform a load flow analysis in the system using NEWTON RAPHSON Method. The size of Newton Raphson Jacobian Matrix is