Tuesday, March 30, 2010

Advantages of using IEC61850 Protocol

Advantages of using IEC61850 Protocol

1. Reduced Hardwiring
2. Improved Performance
3. Improved capability
4. Customized Solutions
5. Flexibility of the various protection/control schemes
6. Improved supervision
7. Trouble shooting much easier
8. Reduced man-power requirement
9. Reduced chances of error
10. Faster completion of project
11. Reduced space requirement
12. Improved functionality
13. Easy to carry out changes/modifications
14. No aging issues

Saturday, March 13, 2010

AutoReclose Function in Protection Relays

Auto Reclose Function:

Technically, whenever any transient faults causing the trip of the circuit breaker, mainly for Over head lines occur, most of utilities prefer to reclose the breaker or they try to reclose for number of times, before coming to the conclusion that the fault is permanent.



You must know which kind of faults you need to consider for transient faults. Not all faults are transient. Ph-Gd, O/C or Multi-phase faults generally account for Transient faults. These AR initiation can be other source too. Energized by user-defined precondition to start AR. As per Siemens Relays, Non-directional faults/Directional/Other/via BI is possible. But it is important that fault occurs. Unless relay sees a fault and breaker trips due to that fault, AR sequence will not start.


  • AR and Synch Check goes hand in hand. So when you configure any protection, enable 79 (for auto-reclose)and 25(for synch check).

  • So, to first know what is AR and then what is synch check to understand AR sequence.

  • it is also important to know Power System Data, V, f, VT connection, Vsynch connection, etc.

  • Always set the AutoReclose function.

  • Use Inbuilt function for checking how auto reclose works by initiating Overcurrent fault.

  • Check then how the sequence is initiated.

















Source:

1. Siemens Manual for Line Relay 7SA522/

http://siemens.siprotec.de/download_neu/index_e.htm