It is expected that the overall standard of presentation will be high and untidy or disorganized reports will be penalized. The quality of the network model is also important. While you may work on the network model with others, the report must be your own work; you must not copy from others. Any reference material you use must be acknowledged.
Submit the report to the Faculty of Engineering and Environment, faculty office (Ellison Building, Room B201), no later than 29th January 2016. You must complete the Assignment Submission Form which is available from the Faculty office. You may obtain and complete the form in advance and you will be allowed to hand the work in prior to the submission date. A copy of this form will be returned to you as a receipt. Keep this receipt safely as it is proof that you have submitted the Assignment.
A copy of the CD, which includes the network computer model and a copy of the report, must be submitted with the report. The report should be clearly labelled with student’s name, module number and name.
Before you run ERACS package, create ‘Library’ and ‘Work’ folders in drive F. The former will hold all the library files that you create and the latter will hold the network files. To do this, run the Windows Explorer from the Start, Programs menu.
60 MVA X=11%
Bus 3 b
30 MVA X=0.1 p.u.
X=24.3 /ph Overhead line
Note that all files that you create on drive F are automatically deleted when you logout. Therefore, before you logout, make sure to copy (backup) all your files (saved in ‘Library’ and ‘Work’ folders) to the U drive or a memory stick.
4.2 Run the ERACS package from the START menu and choose User Name as student and password as student.
4.3 The first time you use ERACS, you need to create a new database by selecting New Database from the Database menu. Note that you need to be in the ‘Work’ folder in drive F.
4.4 From the File menu select New Network and set Network Name and Data State Name. You need to assign a project library from Libraries menu. Select a name for Project Library 1 and save it into the ‘Library’ folder in drive F. You may choose Project Library 2 as the Reference Library, by selecting Existing Library (ERA_Reference_Library) from the subdirectory C:Programme FilesERACS Libraries.
4.5 Follow the instructions given in the Help menu to construct the network given.
Notice that you need to create each element of the network and save it in Project Library 1 (in drive F) by selecting Library and New for each element. Then, Select the element from the Library Key list. Also, C.B.1 and C.B.2 are modeled as part of the bus section. Further, generator G is modelled as a PQ type with assigned active power of P = 30 MW and reactive power of Q = 20 MVAr.
Also, notice that the resistances of all components in the network are assumed to be zero. Furthermore, for the generator and transformers, select “Neutral Earthing Data” with zero neutral earthing resistance and reactance.
Throughout this work, make any necessary approximations and assumptions required to simplify the design and state these in your report.
4.6 From Calculate menu choose Load Flow and perform the Load Flow analysis, with circuit breakers C.B.1 and C.B.2 closed. Accept all the default values for the negative and zero sequence components during running of the program.
4.7 From the Results menu choose Select Data / Results and Load flow, then:
(i) Busbar: Voltage (p.u.) , Fault level (MVA)
(ii) Line Real power (MW)
Voltage (kV) , Voltage angle ( o ) , Three Phase and Three Phase Fault current (kA)
and Reactive power (MVAr).
(iii) For Cable, Transformer, Synchronous Machine and Shunt, select the same as in (ii).
From Results menu, choose Show Results to display the selected results and record them
(from File menu choose Print and then Network Diagram). You may need to adjust the layout of the results before you print; refer to the User Guide.
4.8 Comment on the results obtained with regard to the main factors that largely determine the flow of active and reactive power through different parts of the network. Also, comment on the values of fault level at different busbars in the system.
4.9 Change the rating of Load 1 to 20 MW at 0.96 p.f. lagging, and load 2 to 25 MW at 0.98 lagging. Perform the Load Flow Analysis and repeat step (4.8). Compare these results with those obtained in step (4.8) and comment on the difference.
4.10 Open circuit breakers C.B.1 and C.B.2, perform the Load Flow Analysis and repeat step (4.8). Compare the results obtained with those obtained in step (4.10) and comment on the difference.
4.11 Using analytical procedure, calculate the three-phase fault level (in MVA) and the short- circuit current (in kA) for a three-phase fault on busbar 4. Repeat your calculations for both sections of busbar 4 when C.B.1 and C.B.2 are open. Compare the results obtained from the analytical calculations with those obtained from the computer model and comment.
Every time you finish using the ERACS package, close the network & database created and exit ERACS programme. Before logout, remember to copy your files (‘Library’ and ‘Work’ folders) to the U drive or a memory stick.
Summarize your conclusions, commenting on the balance of active and reactive power in electrical networks, definition of fault level, reasons to carry out fault level calculations and factors affecting power network safety. Also, comment on the usefulness of the assignment.