Old electromechanicl relay GEC CTG25 1

[DiMiTKo]

Hi everyone, I have got maintenance in one substation and one of the electromechanical relays had a problem so the local guys decided to replace it. The old relay is CTG25 (GEC) and it has two stages Overcurrent, one with IDMT curve, and instantaneous stage. The problem is that measured tripping time does not correspond to any IDMT curves from nowadays. I also can't find the manual for this relay. I found for all other old relays, but not for this one. Is there anyone who have manual or can advise me how to transfer the same settings from the old relay to the new digital relay?

 

[Hoxton123]

Oh dear.

The gTg series were a GEC UK (not the USA General Electric) attempt to produce an electronic distribution protection relay in think the 1970s. The ‘T’ stands for transistor. the settings followed the mechanical disc relay IDMTL curves. CDG series, the D standing for disc. Unfortunately I don’t any longer have the brochures.

GEC Measurements fell foul of the merger with Alstom et al.

Some of the range is still sold by GE (USA General Electric)

https://www.gegridsolutions.com/products/brochures/mfac-brochure-en-2018-08-grid-ga-0727.pdf

Good luck with trying them to support this legacy product.

You could try P&B

https://www.pbsigroup.com/latest-news/

Or Slaters

https://slaters-electricals.com/

Please let us know if you succeed in your quest.

 

[Sn00ze]

I remember reaching out to get a hold of a manual for an old electromechanical relay a while back. Sorry I don't remember which.

This was an old obsoleted model and they were able to get me a manual, so i recommend you reach out directly to the manufacturer and ask for it. You may get lucky.

All the best.

 

[9wearSuave]

Had a situation similar to this where we had to measure all the trip points in the old relay and select a curve that best fit the old curve.