Outdoor Transformer location
Outdoor Transformer location
(OP)
I am specifying/installing (4) 3MVA transformers that are to be located outside in the US in a hot/tropical climate (HI). It needs to be as close to the building as allowable and each other. I am looking for a guideline/standard on placing outdoor transformers. The NEC only mentions providing adequate ventillation for transformers.
I found this in IEEE C57.12.01 - 4.1.2 Temperature
The temperature of the cooling air (ambient temperature) shall not exceed 40 ºC, and the average
temperature of the cooling air for any 24-hour period shall not exceed 30 ºC.
The minimum ambient temperature shall not be lower than –30 ºC.
Does anybody know of any other standards or guidelines for installing these?
The team wants to place them right by the building and next to each other and need some help figuring this out.
Thanks.
I found this in IEEE C57.12.01 - 4.1.2 Temperature
The temperature of the cooling air (ambient temperature) shall not exceed 40 ºC, and the average
temperature of the cooling air for any 24-hour period shall not exceed 30 ºC.
The minimum ambient temperature shall not be lower than –30 ºC.
Does anybody know of any other standards or guidelines for installing these?
The team wants to place them right by the building and next to each other and need some help figuring this out.
Thanks.






RE: Outdoor Transformer location
RE: Outdoor Transformer location
RE: Outdoor Transformer location
Four transformers placed line-of sight and fairly close to each other: should one of the centre units fail explosively it could well take out the transformers on either side of it as well...
Unless the entire facility is taken out of service and off potential at once for simultaneous maintenance on all transformers, adequate clearance will have to be provided to comply with the limits of approach to energized equipment such that work can be safely performed on one bank at a time. This will additionally provide adequate room for air to circulate around the units' cooling facilities.
Because of the foregoing it might be wise to place a rigid non-conductive flameproof barrier between each unit and its neighbour. Such a barrier can also provide worker safety by virtually eliminating any risk of electrical contact with live components while maintenace is being performed.
As noted above, it may become necessary to increase the fire resistance rating of the building's wall adjacent to the transformers.
RE: Outdoor Transformer location
RE: Outdoor Transformer location
Once you get the spacing from the building, then you will want to allow similar apacing between each unit. This will also depend on the type of transformer. Are these pad-mounted or substation type? If substation type - just self-cooled, or with fans?
Assuming these are oil-filled, if reliability is of high concern, some type of fire barrier between the units may be desirable - it won't be an NEC requirement. The insurance underwriters often have their own requirements and guidelines that can be more restrictive than the NEC.
I don't think the -30 C will be a problem in HI.