Undervoltae relay and earthfaults detection

[PUNGLU]

Hallo guys,
need help on the 7RW6000 undervoltage relay. Can this relay be connected on the delta side of a Star/Delta transformer to detect eartfaults in the transformer when the Delta side autorecloser is open.

Regards,
Punglu

 

[slavag]

Hi Punglu.
Where is VT instaLled ? What is a VT connection type:
phase to ground(earth) or ohase to phase?
Theoreticaly possible use undervoltage relay, it will blocked by trafo LV CB close posotion, practicaly, I never see it's before. More better use broken delta detection principle., possible use relay with internally broken delta calculation , you can use Siprotec too.
Best Regards.
Slava

 

[RRaghunath]

Punglu,
"7RW6000 for detecting Earth fault protection on delta side" Yes, can be used.

Required: 3-phase VT located between transformer and Auto recloser with windings connected in broken delta.
Broken delta voltage is wired to 7RW and the relay set as residual overvoltage relay (59N), that is, the relay will pickup and provide output when the residual voltage sensed is more than the set point.
Typical setting would be 5V with a time delay of say, 2sec.

 

[PUNGLU]

Yes, the VTs are positioned between the trafo and the autorecloser. There is a possibility of V connection and the broken delta connection. They are single phase units and I acn be able to connect them to suit my needs

Thank you

 

[PUNGLU]

I would like to use the overvoltage function as to detect the zero sequence residual voltage and be able to trip the breaker on the trafo LV side.

The relay, 7RW6000-2EA00-0DA00/BB, seem trip only on the undervoltage function. It can detect and annunciate an overvoltage but I cant get the contact to trip the breaker.

Anything I may have overlooked?

 

[slavag]

Hi Punglu.
Please see manual of relay.

http://siemens.siprotec.de/download_neu/devices/7RW600/Manual/7RW600_V1_Manual.pdf

Please check yourself again, this relay is include overvoltage protection.
Best Regards.
Slava

 

[slavag]

And new one

http://siemens.siprotec.de/download_neu/devices/7RW600/Manual/7RW600_V3_Manual.pdf

 

[PUNGLU]

Thank you guys!! I managed to get the manual and marshall the outputs to trip for an overvoltage. The scheme works very well.