Transformer of outgoing cable 1

[kashun]

Hi all,

I've some question about transformer. If a transformer has a rating 11kV to 380V, there's four incoming cables, Neutral, Red phase, White phase and Blue phase from CLP, how many cables are going out from the transformer? Is it still have four outgoing cables? And what is the voltage in each cable?

Many thanks

 

[richanton]

It depends on the transformer. Since you have 4 wires on the primary, it is wye connected on the high side. If the secondary only has 3 wires then it is probably delta connected, which means you would have 380 volts, 1 phase using 2 wires, or 380 volt 3 phase using 3 wires. If you have 4 wires on the secondary, then you have a neutral, and you could get 380 divided by the square root of 3 volts using one pphase conductor and the neutral.

Look at the secondary terminals. Does it have xo,x1,x2,x3. If so, it is 4 wire secondary.

 

[jbartos]

Suggestion: Try to obtain one line or schematic diagram of the power distribution system. It is the power distribution system and direction of power flow that are usually governing, not the transformer terminals. E.g. The primary of the transformer may have four wires; however, it may be required to be ungrounded, depending on the system grounding upstream. Similarly, the transformer secondary side the system voltage and the system grounding should not be overlooked.

 

[Labbakutur]

In addition to what has already been said, the nameplate of the transformer might have the answer. If the nameplate sais wye-delta connection, you only have 3 outgoing cables and the voltage between any 2 of them is 380V. If the name-plate sais wye-wye connection, you can have 3 outgoing cables or 4 outgoing cables (in the case of neutral conductor) and in both cases the voltage between two phase cables is 380V but the voltage between any phase and neutral is 220V.

My apologies if I am pointing out the obvious or repeating from the former posts

Labbakútur

 

[jbartos]

Suggestion to the previous posting: Every added bit counts