Learning Outcomes
The purpose of this practical is to further deepen our experience in:
1. PowerWorld for the simulation and ANALYSIS of power systems
PowerWorld should already be installed on the lab computers. In the event that it's not and you would like to install it on your own laptop, you may download it from the PowerWorld website at:
https://www.powerworld.com/download-purchase/demo-software (PowerWorld Simulator- Version 19)
Reading Material and References
The following reading material and references are recommended to help you though the practical. These are by no means the best or only references on the work. You are encouraged to find and identify additional references as you work through the practical.
PowerWorld Project
Work through the following steps and implement each of the requirements. Your final mark for this practical will be based on how far you get through the practical and the results of the exercises and discussions given in your report.
A one line diagram, together with the bus and line data, of a 5-bus power system is shown below; the system will be referred to as utility A. Solve the following problems using PowerWorld Simulator and the original data files 454_0.pwb and the one-line diagram file 454_0.pwd (available on Ulink).
Initial Bus Records
Fig. 1. One line Diagram of Utility A
Bus PU Volt Volt (kV) Angle (Deg) Load MW Load MVR Gen MW Gen MVR
1 1.05000 15.75 -0.500 80.00 40.00 520.00 238.94
2 1.00000 15.00 0.000 390.70 26.16
3 0.87580 302.15 -21.256 800.00 280.00
4 1.02871 354.90 -2.755
5 0.99196 342.23 -4.495
Line Records (Base MVA = 400)
From To Xfrmr R X B MVA Lim
4 1 Yes 0.00300 0.04000 0.00 1000.0
2 5 Yes 0.00600 0.08000 0.00 600.0
4 3 No 0.03600 0.40000 0.44 1200.0
5 3 No 0.01800 0.20000 0.44 1200.0
4 5 No 0.00900 0.10000 0.22 1200.0
1. For the power system of utility A, use the PowerWorld program to find the MVAr rating of a shunt capacitor at bus 3 that increases V3 to 1.00 p.u. Determine the effect of the capacitor bank on the line loading and total I2R losses.
2. Run the original power flow for utility A. Do you find any voltage violations? (The normal range of bus voltages is assumed to be 0.95-1.05 p.u.) Now suppose both transformers in this system are tap changing transformers whose taps can be varied from 0.85 to 1.15 p.u. in increments of 0.05 p.u. Determine the tap settings required to increase the voltage at bus 3 to 0.95 p.u., while causing as few high voltage violations as possible at the other buses.
3. A new transformer is installed between buses 2 and 5, in parallel with the existing transformer between buses 2 and 5. The new transformer is identical to the existing transformer. The taps on both transformers are set to the nominal value, 1.0 p.u. Find the real power, reactive power and MVA supplied by each of these transformers to bus 5.
4. Refer to the one-line diagram of utility A. Suppose an additional line is installed between buses 3 and 4. The line parameters of the added line are equal to those of the existing line 3-4. Determine the effects on the voltage at bus 3, line loading and total I2R losses.
5. In problem 2 you already ran the power flow for utility A and detected low voltage violations. Place a capacitor at bus 3 to bring the bus 3 voltage up to 0.95 p.u. Determine the size of the capacitor bank. Now suppose the line between buses 3 and 5 is removed for maintenance. Run the power flow again. Is the operating condition acceptable? If not, determine the amount of load you have to shed at bus 3 in order to maintain the bus 3 voltage above 0.95 p.u.