Question 1

A boiler generates 5000 kg of steam per hour. The specific enthalpy of the steam is 3600 kJ/kg and the specific enthalpy of the water supplied to the boiler is 300 kJ/kg. The calorific value of the fuel oil is 45 MJ/Kg.

• Determine the amount of fuel oil supplied assuming the heat process is 70 % efficient.

(10 marks)

• If the steam raised in the above example is supplied to the steam turbine and the enthalpy of the water steam mixture at the turbine outlet is 2700 kJ/kg. Determine the power output from the steam turbine. Assume the losses in the turbine amounts to 12 %.

(10 marks)

• For 5000 kg/hr fuel used estimate the carbon emission per year for each fuel and Comment on the results obtained

Fuel A: Diesel with carbon emission factor 3.15 kg CO2/kg

Fuel B: Coal with carbon emission factor 2.4 kg CO2/kg

Note: Total carbon emission per year =Fuel consumption per year ×Carbon emission factor

(10 marks)

• What are the benefits of replacing the fossil fuel mentioned in Q1.c with renewable source?

(10 marks)

[Total marks 40]

Question 2

A Three-bus power system is shown in Figure Q2.

Figure Q2

The data for the buses are given in the Table Q2 A to E below.

Table Q2.A: Bus Data

Table Q2.B: Generator data

Table Q2.C: Line Data

Table Q2.D: Load data

Table Q2.E: Reactive power Compensator

1. From The Network Details we find that Line 1,2 and 3 are using same type of cable with R= 0.005 Ω /km and X= 0.001 Ω /km, observe table Q2.C try to theoretical find the R_pu, X_pu and B_pu Comment on the pu values obtained.
   (5 marks)
2. Follow the instructions given in Table Q2 B to D to construct the network using “Power World” software.
   NOTE: System base no changes applied default base MVA will be 100 MVA.
   All the field values such as voltage and phase angle at every bus and real and reactive power at both end of every line must be included in the circuit.
   The created network (before simulation) must be included in your report.
   (15 marks)
3. From Tools menu choose solve and perform the Load Flow analysis. The simulated diagram with all the field values clearly shown must be included in your report.
   So to avoid black-out once the loads are added, start the load at 100MW and 100MVAr each slowly increase the load to the set value. Why do you think the variable loads are better handled by generator then a sudden huge load?
   (10 marks)
4. Observe the transmission line loss for line 1 , 2 and 3 respectively without shunt capacitor , include simulation observation of V,P and Q loss on lines and provide theoretically analysis for voltage regulation of line 1 ,2 and 3. Suggest which line might need to be modified to improve the overall efficiency of the system.
   (10 marks)
5. Repeat step C and D with Modified network by adding shunt capacitor and Include information of bus voltage and real and reactive power loss analysis for Modified network. Compare these results with those obtained in step C and D
   (20 marks)

 [Total marks 60]