Testing and Commissioning

Thursday, July 14, 2016

380/230/115/13.8 kV Sub Station Energized

Doha BSP 380/230/115/13.8 kV Sub Station Energized  on 23.06.2016 successfully.  I really appreciate all Engineering and technicians who's hardly working for achieve the target.

The points should consider before Energization 

1. Checks the all transformer and Air busing for temporary earthing.

2. Rack in all MCAG and MFAG relays

3. Close all FTs in the protection panels 

4. Check all CB trip circuit supervision relays 

5. Check all alrams in the SAS monitor and clear unwanted

6. Take 10 copies of Single line diagram.

7. Check all Secondary VT TBs in LCC and VT MCBs in VT Terminal BOX.

8. Check all CT connections in Metrosil & Resistor

9. Check operation off all equipments ( CB, DS ES , RTCC) final kept all equipment in open condition and put LOCAL/REMOTE switch in REMOTE position.

10. The BB block alarm will appear if CB in test position.

11. Keep all Transformer in lower TAP position ( Lowest voltage)

12. All Surge arrestor shorting link in open position

13. Some times Line Zone -2 time setting will be instantaneous ( If recommended)

14. Check Syn function in all LL-LB  LL-DB DL - DB combination ( If possible)

15. Check the Gas levels in Gas monitor and keep GIS gas cylinder and filling machine for back up

16. Open all panels and check IN/OUT switch , open wires, CT VT TBs , all wires should away from the Panel Heater and temporary shorting.

17. Conform the availability of Phase Sequence meter and Multi meter with length leads , and clam meter.

18. Conform Temporary  Final setting for Spare bays ( Stub or Over current )

19. Keep all ACDCs in Auto mode .

SEIMENS Ethernet switch

We are used RUGGEDCOM RSG2100NC  SEIMENS  Ethernet switch was used for SAS net work.

There are two Power supply unit in the switch.

Due to Over Temperature or DC fluctuating or some other reason  one unit was fail nearly 15 nos.

The power unit was changed in the site.

Power Module 



Extra port added in the switch

Monday, June 20, 2016


The CAT 6 shielded cables are used for Substation communication.


1.Switch off the DC 
2. Remove the plugs and CT & VT wires
3. Remove the screws with suitable driver 

4. Remove the cover 
5. Dismantle Input cord carefully 

6. Check the version of the card

7. Reassemble the relay and check the card availability in the Hard ware menu


Generally the contacts used for interlocks should be direct or high speed contacts. We faced a problem in Main AC distribution panel. 

Auto transfer scheme ( ATS) 

As per ATS scheme consider  incomer CB trip due fault then Bus tie should not close in both Automatically or manually.

Same condition if  Bus tie trips incomers should not close in both Auto/Manual condition.

Problem faced Site:

1. Both Incomers are closed and Healthy. Incomer -1 tripped by jumper and tie was automatically not closed. But trip was given by actual current injection and bus tie closed. 

2. Now Incomer -1 and bus tie is closed and Bus tie tripped by jumper and Incomer -2 was automatically not closed. But trip was given by actual current injection Incomer -2  closed.

Same happen for Incomer -2 and Bus tie combination. 

The breaker trip Aux. contact is in serious of other Breaker closing path. This contact should immediately open and block the other CB closing.

But in our circuit tripping Aux contact will pick up a auxiliary relay and this relay contact open the other CB closing path. But pickup time of this relay is little bet  high . During this pick up time adjesend CB was closed. 

So found that problem and replace high speed Aux relay.

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