GE Multilin SR735 Feeder Protection Relay Failures ?

please check at your installation site if you have done everything as required . . . . http://www.gedigitalenergy.com/products/support/735737/7357dd.pdf

i am sure GE will support your queries . . . what is the location of your installation?

1. Pl. check the difference in Maximum Design temperature and actual Max ambient temperature in which relays are operating. PL. check temperature in Metering compartment in which relay are installed.

2. Check if there is difference between rated auxiliary supply voltage and actual availible at site.

3. Check for all source of heating inside metering compartment including malfunction of Thermostatic controled space heater if any.

We have the problems also. Our 735 are fitted in GE Powervac breakers. We have had several failures already and planning to replace them with other brand.

The problems encountered are on the power supply. They are normally powered by 125 DC from a battery bank. When we get an alarm in the DCS, the LED's are all lit. This is solved by supplying the relays with 220 Vac. The relay us with the new power supply passed the tests we performed. I suspect problem in the power supply selection card.

One problem also is the latching of the lock-out/86-5 contact. We don't have any solution for this but to replace the relay. We tried to contact GE, but so far, no word from them.

We have seen numerous power supply failures at our facilities and we have been replacing power supplies and re-calibrating the relays after repair. The relays installed at our site are GE Multilin SR750 and SR469 and both of these relays have been affected. GE Multilin have acknowledged officially of defects with power supplies of SR750 for a particular period and the following are the details that emerged during our communication:

1. Defective Opto-Coupler - SR750 and SR469 relays built in the 2005 production year are potentially affected by an opto-coupler component defect within the unit's power supply cards.

2. Degraded Component - On relays supplied prior to 2005, predominantly 2002 models, an increasing number of failures have become evident, again due to a power supply component failure (capacitor) which GE Multilin has attributed to capacitor ageing'

3. These issues, the 2005 units (Point 1 above) and failed 2002 units (Point 2 above) are corrected by upgrade / exchange of the power supply. Detailed method statement for replacement of the PSU is available from GE Multilin upon request.

Although GE Multilin stated of defects with SR750 and SR469 manufactured during a particular period, actual defect base seems to be much wider in view of defects learnt to be from other models.

Yes, this seem to be a type fault amount GE relays.

I do have some technicians who have repaired them.