Assignment Detail:- ELEC4100 Electrical Systems - University of Newcastle
Power Systems Study Project
The objective of this study is to develop a capacity to conduct the analytical studies sufficient to allow valid and responsible engineering decisions to be made in the context of system planning and operation- To do this we will study the behaviour of a simple -but representative- 18 bus power system, as illustrated in figure 1- The various capabilities of the Power World software will provide sufficient analysis tools for our purpose-
This project is to be conducted on an individual basis-
The study specification provided below is flexible and its intent is to expose students to a realistic system and to observe and interpret its behaviour, rather than simply obtain results for a prescribed set of scenarios- Each student may use a different approach to the factors studied-
Question 1- Begin by entering your "Base Case" system as given into Power World- The Base Case represents the normal high load condition- Examine the power flows and the voltage profile of the network- All load buses should be within normal system tolerances -i-e- 0-95 p-u -1-06 p-u--- Use caution when entering the tap-settings for the transformers -e-g- tap 0-95 on the primary side produces the same effect as tap 1/0-95 on the secondary side--
Question 2- Observe the system behaviour under the condition where any line or transformer is at fault or taken is out of service- This represents the N-1 contingency test- Are there any lines or transformers that can not be taken out of service without the system voltages departing from the acceptable limits -i-e- 0-95 p-u - 1-06 p-u--, or overloading of the remaining transformers and lines???? In particular, are there sections of the network that are marginal???? Power World has a Contingency function which may help- You can tabulate and summarise your results-
Question 3- Define a light load case where the loads are about 40% of those shown- Power World has a Scale Case function which may be useful here -but please save a copy, since in part 5 you will return to the base case again-- Are there any voltages that are unacceptably high or low -and why-???? Suggest a remedial strategy to compensate for any voltages that are out of spec- and verify the effectiveness of the strategy -Note: this should not require any additional capital expenditure, since the light load is a normal situation, which happens every night- Instead, try to use the regulations that already exist in the system-- Discuss the nature and source of problems associated with a lightly loaded system-
Question 4- For the light load case repeat the N-1 contingency test- How does the system behaviour compare to the normal -base case- load???? Maintenance schedules which require a transmission line or transformer to be taken out of service are commonly performed at times where the system is lightly loaded- What capacity does the system have to withstand another line or transformer tripping with one element already out of service for maintenance???? This represents the N-2 contingency test- Study the N-2 contingency at light load and summarise your observations-
Question 5- In parts 2, 3 and 4 you have studied the system ability to tolerate the loss of any line or transformer, under normal and light load- Now suggest a remedial course of action, which will address the problems identified in parts 2, 3 and 4 -this may include additional infrastructure-- Note that the proposed modifications have to be effective but not overly expensive- N-1 contingency has to be fully satisfied at normal load and -with additional regulations- - at light load- N-2 contingency must be "mostly" satisfied at light load, with some exemptions- For, example, some buses are allowed to be "islanded" -have no power supply- under N-2 contingency- Discuss why it is ok in some cases- Verify the effectiveness of the proposed remedial strategy for the same conditions as studied in parts 1, 2, 3 and 4-
The result of part 5 is a modified, more secure and resilient, power system- There is no single "correct answer" to this: each student may have their own solution, as long as it is sensible and justifiable-
Question 6- Take your modified power system under normal load as the new Base Case- A new industrial client is to be connected to the system under the new Base Case scenario- The client has premises located in the vicinity of bus 16 -the distance to the client is approximately twice that between bus 16 and bus 17-, and has an anticipated 33kV demand of 20MVA at 0-8pf lagging- Plan a connection for the new load with redundancy so that the client can still be supplied even if one line feeding it is lost- What effect will the new load have on the system performance???? Can the system tolerate the loss of any line or transformer under the new conditions????
Question 7- Now investigate the anticipated growth of all loads by 50% over the next 10 years, including the newly connected client- Increase all loads in 10% -or so- steps, up to 150% of the Base Case, to observe the limiting factors that the load growth will be facing- The purpose of this exercise is to see what reinforcements and new equipment might be included in the system development plan, as consumer demand increases over time- Make up your own mind as to what reinforcements - extra line, bus, or generation - you decide to add- Their addition should be staged over the next 10 years- Examine the modified system from the viewpoint of -N-1- security-
Question 8- Develop PV and VQ curves for the newly connected bus 19 -new industrial client-- Determine real and reactive power margins- Discuss potential voltage stability issues, and suggests ways to avoid or mitigate them-
Question 9- What is typical of real power loss in the system???? Choose whatever case you wish, and see what happens to losses when fixed generation is altered- Move some generation away from bus 1 to bus 2, or add a generator at a bus elsewhere-
Question 10- Study transient -generator angle- stability for bus 2- Find critical clearing angle, and discuss how to avoid destabilisation of the power system due to the generator angle deviations-
Attachment:- Electrical Systems-rar
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