1. Birla Vishvakarma Mahavidyalaya (Electrical department) Topic:- Laboratory setup for Numerical Protection of transformer
Group No. : 17
Sr no.
Name
Enrolment No. 1
Madhav Dadhaniya 2
Kishan Kamariya 3
Parth Panchal 4
Bhavin Ughareja
Guided by
Dr. R.P.Mehta
Head of Department
Dr. B.R.Parekh

2. Content Introduction Fault in transformer Numerical relay
Power & Control Circuit
Modes of operation and setting procedure
Marshalling of binary inputs
Simulation & Results
References

3. Introduction
The power transformer is one of the most important links in a power system. Because of its relatively simple construction, it is a highly reliable piece of equipment. Being static totally enclosed and oil immersed, it develops faults rarely but the consequence of even a rare fault may be serious unless the transformer is quickly disconnected from the system.
The varied characteristics of the power transformer with different types of faults greatly affect system conditions, which have tended to become more complicated in recent times. It is thus worthwhile to review the different types of faults generally encountered by a transformer before considering the application of protective gear.

4. Fault in transformer
Faults can be divided into two main groups: I) Faults in the auxiliary equipment: Transformer oil. Gas cushion. Oil pumps and Forced Air fans Failure of Insulation Lamination of core. Insulation failure. Badly made joints or connections. Inter tum Faults. 2) Winding Faults: When the insulation between windings and core fails then these types of faults occurs

5. Numerical Relay

6. 7UT5131

7. Functions of 7UT5131 Backup overcurrent protection
Thermal overload protection
Differential protection
Restricted earth fault protection

8. Power Circuit

9. Control Circuit

10. Auxiliary relay:
4 NO contacts
4 NC contacts

11. Modes of operation: Manually Using DIGSI What is DIGSI?
DIGSI (V3.3) is a software provided by Siemens.
It provide batter and easy control while configuring settings of relay.
We can see all the data in organized manner.
It also provides graphical analysis feature using DIGRA program.
Display, storage and printout of measurement and fault data.
It display fault data as an overview.

12. Setting Procedure (Manual):
Go to the respective location in which you want to feed data.
Press the button CW on the front panel and enter the code word that has been selected for the relay.
Press the DA button on the front panel and then enter the address at which you want to access or by means of up and down arrow keys.
Now the cursor is blinking and now you can change the data or enter new data.
For saving the data fed, first button E and then combination of keys F and E i.e. Depressing the function key F followed by the enter key E.
Display shows the question “SAVE NEW SETTING?” confirm with “YES”- key J/Y on the front panel that the new setting shall become valid now.

13. General data of transformer used for configuration of relay :
Rated voltage of winding 1 of transformer 0.8 kV
Rated apparent power of winding MVA
Primary rated current of CT winding A
Star point formation of CT winding 1 Towards transformer
Vector group no of winding
Rated voltage of winding 2 of transformer 0.4 kV
Rated apparent power of winding MVA
Primary rated current of CT winding A
Star point formation of CT winding 2 Towards transformer
Real data of simulated model transformer :
Rated voltage of winding 1 of transformer 400 V
Rated apparent power of winding 1 3*1 KVA
Primary rated current of CT winding A
Rated voltage of winding 2 of transformer 200 V
Primary rated current of CT winding A

14. Marshaling of binary input:
Binary input no.
Function allocated 1
Reset LED indicator 2
Parameter set A is active 3
Parameter set B is active 4
Warning stage from buchholz protection 5
Trip stage from buchholz protection

15. Simulation

16. Results

17. References
B.A.Oza and S. Brahma, Development of Power System Protection Laboratory through senior Design Projects, IEEE transaction on Power System, Vol.20, no 2,pp , May 2005.
Manual of Relay 7UT5131 and MATLAB Software.
“POWER SYSTEM PROTECTION AND SWITCHGEAR” By B. A. Oza, N. C. Nair, R. P. Mehta & V. H. Makwana