Assignment 6 k6o1y

University of Ontario Institute of Technology Faculty of Engineering and Applied Science Department of Electrical Computer and Software Engineering ELEE 3260U: Power Systems

Assignment 6: Due: Nov. 21th / 2016

Fall 2016

Section 1: Transmission Lines (Design Problems): POWERWORLD Simulator 1. Open the POWERWORLD file Example2_32 a 10 MW/5 Mvar load is supplied at 20 kV through a feeder with an impedance of 1.5 + j 3 Ω. The load is compensated with a capacitor whose output, Qcap can be varied in 0.5 Mvar steps between 0 and 10 Mvars. a. What value of Qcap minimizes the real power line losses? Explain how this value of reactive power reduces the line losses? What will happen if you increase more the reactive power above this value? b. What value of Qcap minimizes the MVA power flow into the feeder? Is it the same value of reactive power that you got in part (b)? if different, explain why? c. Plot the real and reactive line losses as Qcap is varied between 0 and 10 Mvars.

2. Open the POWERWORLD file Example 5_4 a. Graph the load bus voltage as a function of load real power (assuming unity power factor at the load). b. What is the maximum amount of real power that can be transferred to the load at unity power factor if we require the load voltage always be greater than 0.9 per unit? Explain why we can’t increase the real power beyond its maximum value? c. Repeat part (b) but now vary the load reactive power assuming the load real power is fixed at 1000 MW. What will happen if we increase more the reactive power beyond this value?

3. Open the POWERWORLD file Example 5_10 with the series capacitive compensation at both ends of the line in service. Graph the load bus voltage as a function of the load real power (assuming unity power factor at the load). What is the maximum amount of real power that can be transferred to the load at unity power factor if we require the load voltage always be greater than 0.85 per unit?

4. Still with Example 5_10, with the reactive power load fixed at 500 Mvar, plot the load bus voltage as the MW load is varied between 0 and 2600 MW in 200 MW increments when the capacitive compensation at both ends is in service and when it is not in service on the same graph. What is the effect of the series compensation in this case?

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Section 2: Power Flow (Design Problems) MATLAB computing environment

1. For the following power system with shown configuration with Bus and Line data:

1. In power system networks, it is desired to keep bus voltages within ± 5% from nominal value (1 p.u). Usually, voltage-controlled buses will tend to have higher voltages than slack bus while load buses voltage will be less than slack bus. Run your M-file and analyze results from MATLAB workspace. Do your results agree with the desired voltage requirements? 2. Assume that load forecast analysis predicts an increase in the power demanded in the next five years, in order to meet these demands a new generator rated 420 MW is installed at bus 3 to bring the total bus generation to 480 MW. Modify your 2

program to calculate power flow in the future. Do all bus voltages fall within the allowable limits? One way to regulate bus voltages is to install shunt capacitor banks. Place 20 Mvar shunt capacitor bank on the “needed” bus to regulate its voltage and study its effect.

3. If line 3-6 is dropped due to disturbance, analyze its impact on the system (i.e. bus voltages and transmission line loading). If all transmission lines have a maximum MVA rating of 60 MVA, list all transmission lines that violate its operating limit. 4. If any bus voltage in part (3) is not within the desired limits, how can you correct this? 5. For the above steps, print out your input and output files.

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