Two DNO 11Kv/400/230v transformers on different HV lines originally supplied two separate buildings on an industrial site. The two separate buildings are now one large steel framed one. So we have two DNO intakes and no clear demarcation within the installation. I remember reading somewhere about issues arising in such situations but cannot find the article. I am keen to establish if any issues are serious enough to seek alternatives. One of the intakes has a Biomass plant feed-in with g59 relay. Both intakes are circa 1MVA.
Not usually a problem, if the HV (MV) side is coordinated - ie are they derived from the same source, or if not is each source synchronised. Then you just need the transformers to be of the same vector group.
You then have a common platform with common earthing and bonding.
As a fairly extreme example, a client of ours on a recent project has 2 x 60MVA supplies into one building from a pair of 33kV feeders (The 33/11kV transformers are within the curtilage but outside the building). He has 40 x 11/.4kV transformers and a potential for 60 x 1.5MVA Generators all connected at the same time - there are a number of earthing transformers in place as well as the generators act at 11kV
Speak with the DNO, but as it's likely that both supplies are from the same HV Feeder, than all they would want is a big earth cable between each intake (which could be the steel frame of the shed)
Not usually a problem, if the HV (MV) side is coordinated - ie are they derived from the same source, or if not is each source synchronised. Then you just need the transformers to be of the same vector group.
You then have a common platform with common earthing and bonding.
As a fairly extreme example, a client of ours on a recent project has 2 x 60MVA supplies into one building from a pair of 33kV feeders (The 33/11kV transformers are within the curtilage but outside the building). He has 40 x 11/.4kV transformers and a potential for 60 x 1.5MVA Generators all connected at the same time - there are a number of earthing transformers in place as well as the generators act at 11kV
Speak with the DNO, but as it's likely that both supplies are from the same HV Feeder, than all they would want is a big earth cable between each intake (which could be the steel frame of the shed)
