Basler BE1 Overcurrent Relay Tripping Breaker

[ATSman]

Had a customer call regarding the tripping of a C-H 4160V VCP vacuum breaker in a auto transfer scheme lineup. After checking the load (bldg power/lights, tel power) for evidence of a fault downstream he was able to reset the 86 LO relay without incident. About a month later the breaker tripped again and was reset. When I arrived onsite after the second trip I found the instantaneous target lit on the B phase Basler OC relay (see pics attached.) No other trip targets were lit on the other phase or ground OC relays which seems strange since most faults start as a ground fault.
We are scheduled to swap out the B phase relay today with a spare to rule out a defective relay. I spoke with a relay tester and he mentioned something about a problem that Basler had with this vintage OC relay (approx 14 yrs.) Had to do with the mis-firing of the SCR at the relay output.
Has anyone experienced a problem with this particular relay or any other protective relay. I have seen older W, GE, ITE and Hi-Z GFR's nuisance tripping but not a relay of this type. Any comments are welcomed.
Forgot to mention that there are no 4160V loads fed from this breaker, only 480V loads thru stepdown xfmrs.

 

[SG-1]

I would suggest setting up the IQ Analyzer to record the over current event, in addition to what you are already planning.

 

[ATSman]

I would suggest setting up the IQ Analyzer to record the over current event, in addition to what you are already planning.

SG
Forgot to mention that I briefly checked the IQ event log but could not find any trip events. As you said it may not be programmed to trigger an event. But if the ATS-1 breaker doesn't trip again and the spare breaker (normally closed) does, then that pretty much nails the relay as the culprit.

 

[Bugman1400]

I would test the relay. I checked my black book and did not have any notes about this relay but, obviously, that doesn't mean there is not a Bulletin out there. If the scheme is to protect the cable and not the xfmr then perhaps the 50 element can be removed/disabled. My concern is that there is some transient that is causing the nuisance trip. I can't even count how many times I've seen the relay terminal wire taped up to disable the 50 element as a result of nuisance tripping. The alternative is to replace with a processor based relay that has event capture capabilities. You can get one for this application for about $1000 (Schweitzer SEL-501 or SEL-551) with minimal installation effort.

 

[ATSman]

The Phase B relay was tested and the instantaneous element tripped at 37A when it was suppose to be set at 60A. It appears the inst PU dial was not set exactly on the 60 mark and it defaulted to a lower PU value (you can actually see this in the pic I attached.) The relay was swapped with a spare that was also tested and the settings verified. We found out later that this breaker feeds loads that included one 600T and two 300T chillers which could have raised the current inrush level above the 37A level.

I also found this interesting statement in the instruction manual for the BE1-51 relay under the Maintenance Section 6:
"Storage
This protective relay contains aluminum electrolytic capacitors which generally have a life expectancy in excess of 10 years at storage temperatures less than 40 Deg C. Typically the life expectancy of the capacitor is cut in half for every 10 Deg C rise in temperature. Storage life can be extended if, at 1 yr intervals, power is applied to the relay for a period of 30 minutes."

We find that the most common reason for nuisance tripping of solid state protective devices is the change of value in these capacitors over time.

 

[SG-1]

If you read the relay manuals for most modern relays they will tell you the same thing, to energize them once a year while in storage.

If all the devices in that panel are the same vintage as the Westinghouse EZC indicating lights they should consider replacing all of the protective devices with new.

 

[zbang]

If you read the relay manuals for most modern relays they will tell you the same thing, to energize them once a year while in storage.

This is true for most electronics; the caps can degrade and dry out over time (even if in use). Usually affects the signal caps more, or it's more visible there, but it still hits the power supplies. Also depends somewhat on the era of the caps, seems like the 1970's were not a good decade for capacitor manufacture.

Before the rise of HD TV, many public-access stations would get older equipment from broadcast stations and volunteers would "re-cap" entire cameras and monitors. Not worth paying a tech to do it, but if you have free labor.... IIRC someone was even selling full "cap kits" for Sony monitors.

 

[ATSman]

Thanks to everyone for all the replies!