Sudden Pressure and Low oil Level TRIPS for < 5MVA Dist. Transformers
Sudden Pressure and Low oil Level TRIPS for < 5MVA Dist. Transformers
(OP)
I have a customer that has recently installed a 4.75 MVA distribution transformer (23/4.2kV)that comes on a skid that also has a recloser, regulators, and isolation/bypass switches. I have fuses protecting the transformer on the high-side. The only trips on the transformer were for 63FPX (Sudden pressure), 71Q (Low oil Level), and 81F (U.Freq). Now the customer just received the transformer and the 63FPX and 71Q devices on it don't have TRIP level contacts, only Alarm level (and there's one of each, no extras to program for Tripping).
So question is: For a small transformer like this, is it OK to not have 63FP and 71Q protection? Should I OK the design, or ask them to have the 63FP and 71Q relays installed before puttng this TXfmr in service?
I don't have a lot of experience with small Txfmrs like this, so any help would be appreciated.
Thanks.
So question is: For a small transformer like this, is it OK to not have 63FP and 71Q protection? Should I OK the design, or ask them to have the 63FP and 71Q relays installed before puttng this TXfmr in service?
I don't have a lot of experience with small Txfmrs like this, so any help would be appreciated.
Thanks.






RE: Sudden Pressure and Low oil Level TRIPS for < 5MVA Dist. Transformers
RE: Sudden Pressure and Low oil Level TRIPS for < 5MVA Dist. Transformers
RE: Sudden Pressure and Low oil Level TRIPS for < 5MVA Dist. Transformers
As for the question "Is it OK?" - it depends. There are thousands of transformers larger than this one that have only primary fuses for protection. This is because of cost. Is it worth spending an extra $100K to reduce potential transformer damage? That depends on how costly an extended outage would be, alternate power sources, available replacement transformers, and the cheapskate index of the owner.
RE: Sudden Pressure and Low oil Level TRIPS for < 5MVA Dist. Transformers