isolation transformer
isolation transformer
(OP)
In my plant there are two substations which have 480 V system, due to some mistake the upstream MCC bus was made 3p+E & the downstream 3P+E+N , now to correct the system isolation transformer (delta\star) are used in the design.What are the Critical Points related to isolation transformers which should be taken care of
thanks in advance
ZAZA
thanks in advance
ZAZA






RE: isolation transformer
Impedance
Neutral earthing
All of which have an impact on downstream fault levels and protection settings. watch for unexpectedly high volt-drops at point of use due to the additional transformer impedance.
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If we learn from our mistakes I'm getting a great education!
RE: isolation transformer
What do you mean by upstream and downstream?
RE: isolation transformer
The isolation transformer will create a separately derived system. The isolating transformer neutral must be earthed (or not earthed) in accordance with local codes.
Bill
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"Why not the best?"
Jimmy Carter
RE: isolation transformer
RE: isolation transformer
Substation 1 has 480 V MCC (3P+E NO NEUTRAL),from the same substation supply is directly going to 480V MCC in substation 2(3P+Earth+Neutral).But we can not run the Loads as we dont have NEUTRAL.So now in the Modification isolation transformers are required.The rating is 650KVA,DYN5.Percenatge impedance i dont know.The grounding system in the substation1 is high resistive grounding.The grounding system in substation 2 will be now made solid grounig type(Neutral directly earthed)
My plant is not near river, upstream & downstream were used for system
thanks
RE: isolation transformer
You could save the cost of a neutral by putting the isolation transformer in Sub 2.
RE: isolation transformer
thanks for your support
RE: isolation transformer
1. A smaller common control transformer for the entire MCC or
2. Control transformers at each starter cubicle.
RE: isolation transformer