system protection

The Project report should contain the following:
1- System network with data as given above
2- Calculations of per unit impedance
3- Per unit single line diagram
4- Fault currents calculation in per unit and in amps.
5- Relay pickup calculation for R1 to R4
6- Calculation of parameters during primary / backup at each fault current
7- Summary results table
8- Plotting the graphs (complete the given graph add R2, R3 and R4)
9- Curves coordination discussion
10- Unit protection (you have an option to choose either earth fault relay, directional relay or
reverse power relay and explain in details how they operate during normal and faulty
conditions)

Design Project

A – Case Study (CLO 1-3)

The system in Figure 1 below represents a radial system network, which consists of two downstream fuses, four overcurrent relays and two power transformers.

In order to carry out a system analysis before a relay coordination study of the system, it is necessary to refer all the system impedances to a common base and thus using 10MVA as the reference base. Let the discrimination between relays be 0.4 sec.

This is a challenging problem for the students to test their knowledge gain from the course ELE 4353. The student has to work out how to plot all the curves using the data given and discuss the coordination between the relays at each level.

PROJECT REPORT (Submit in BBL)

The Project report should contain the following:

1- System network with data as given above 2- Calculations of per unit impedance

• Per unit single line diagram
• Fault currents calculation in per unit and in 5- Relay pickup calculation for R1 to R4
• Calculation of parameters during primary / backup at each fault
• Summary results table
• Plotting the graphs (complete the given graph add R2, R3 and R4) 9- Curves coordination discussion

10- Unit protection (you have an option to choose either earth fault relay, directional relay or reverse power relay and explain in details how they operate during normal and faulty conditions)

Notes:

• I suggest that you solve the problem using excel application. How?

You enter all your data in each cell as shown below and start writing the right formula using excel program example shown Xt1 = 17.5. If you make any mistake, you do not have to redo everything, you just need to correct the mistake at a particular cell and everything will be automatically modified. Using excel, you will save time. If you use excel application for your calculations, copy paste the entire sheet in word document and upload the excel sheet file in BB learn along with the report.

• Summarize your data in table below

• Plot the three remaining curves on 3.3kV side because checking the coordination between the relays on the same voltage side 3.3kV will be easy. As a hint, the expected characteristics of the fuses and relay R1 are given in the graph below. Use this graph to complete plotting other curves R2, R3, and R4

B- Unit Protection: (CLO # 4)

Propose any system that protects either the alternator, transformer, feeder or bus bar.

Draw the circuit diagram and explain how it works under normal and abnormal conditions supported by some real numerical values.