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NORTHUMBRIA UNIVERSITY

SCHOOL OF COMPUTING, ENGINEERING AND INFORMATION SCIENCES

Directed Learning Computer Aided Power System Design and Analysis

Aims

To familiarize the student with the main features of ERACS software package and its use for diagram building and Load Flow analysis in power systems.

Introduction The ERACS package comprises the following routines:

1. Diagram building and Display 2. Load Flow 3. Fault 4. Harmonic Injection

5. Harmonic Impedance 6. Transient Stability 7. Protection Co-ordination

The first item (Diagram building and Display) is the main building block which is essential to run all other routines. The first two items are explored in this tutorial. An example power system network will be constructed and load flow analysis performed.

Through out this work, refer to the ERACS online support available in the Help menu. Please try to do Tutorial 1: Creating a network and Tutorial 2: Power system example, both avialble in Help, Tutorials menu. For adddtional help and technical support, refer to the User Guide and Technical Manual, available in Help, Manuals menu. Please note that the set up for ERACS software at Northumbria is slightly different from that described in the Help menu. When doing this tutorial, it is better if you could follow the set up explained in the following section.

You are encouraged to keep a logbook to record your progress.

Procedure 1) Before you run ERACS package, create Library and Work folders in drive F. The

former will hold 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. Note that all files created on drive F will be 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.

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2) Run the ERACS package from the Start menu and choose User Name as student and password as student.

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 Work folder in drive F.

4) From the File menu select New Network and set Network Name and Data State Name. You need to assign 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 Files\ERACS\Libraries.

5) Follow the instructions given in the online help menu to construct the example power system network. 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.

6) From Calculate menu choose Load Flow and perform the Load Flow analysis.

7) From the Results menu choose Select Data / Results and Load flow, then:

(i) Busbar: Voltage (p.u.) , Voltage (kV) , Voltage angle ( o ) , Three Phase Fault level (MVA) and Three Phase Fault current (kA)

(ii) Line Real power (MW) and Reactive power (MVAr).

(iii) For Cable, Transformer, Synchronous Machine and Shunt, select the same as in (ii).

8) 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.

Make any necessary approximations and assumptions required to simplify the design.

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.

References 1) ERACS User Guide and Technical Manual, available in the online Help menu

2) CHAPMAN, S.: Electric Machinery and Power System Fundamentals, (McGraw Hill), 2002. 3) PUTRUS, G. A.: Lectures notes Power Systems.

Dr G A Putrus September 2009

Course notes\EN0215\ERACS Directed Learning 2009