What is current return path in 230V European single phase

[tor2006]

My question is :what is the role of neutral conductor in the 230v European single-phase system .My assumption how it works that a neutral conductor serves to close the circuit between phases and to carry the imbalance current between different phases If all the phases are balanced then the neutral conductor does not caries the current but closes the circuit between different phases .?

 

[Vitro]

My question is :what is the role of neutral conductor in the 230v European single-phase system .My assumption how it works that a neutral conductor serves to close the circuit between phases and to carry the imbalance current between different phases If all the phases are balanced then the neutral conductor does not caries the current but closes the circuit between different phases .?

Yes, pretty much. The neutral wire in a single phase outlet does carry the full return current up to the point where it joins the neutrals for the other two phases. There the three return currents add 120deg out of phase (assuming net resistive load on each phase) and cancel out if the loads are balanced. The neutral point of the 3-phase star is usually earthed and the Earth provides the return path of the imbalance current back to the power station. This earthing also fixes the neutral point so that it doesn't "float", preventing over-voltage when loads are imbalanced.

 

[Svein]

My question is :what is the role of neutral conductor in the 230v European single-phase system .My assumption how it works that a neutral conductor serves to close the circuit between phases and to carry the imbalance current between different phases If all the phases are balanced then the neutral conductor does not caries the current but closes the circuit between different phases .?

Your figure illustrates a "400V four-lead distribution". You also have a system without "neutral" - the delta configuration: "230V three-lead distribution". The latter is dominant in Norway for two reasons - our geology implies a fairly high impedance ground connection and, of course, 4 leads are 33% more expensive than 3 leads.

 

[tech99]

Yes, pretty much. The neutral wire in a single phase outlet does carry the full return current up to the point where it joins the neutrals for the other two phases. There the three return currents add 120deg out of phase (assuming net resistive load on each phase) and cancel out if the loads are balanced. The neutral point of the 3-phase star is usually earthed and the Earth provides the return path of the imbalance current back to the power station. This earthing also fixes the neutral point so that it doesn't "float", preventing over-voltage when loads are imbalanced.

Not sure about the imbalance current flowing back to the power station because it is isolated by the step down transformer and only appears on the secondary side. The star point is not provide with a circuit to anywhere but is just held at Earth potential.
The neutral is also used for the Earth wire at the premises, connected to a third pin on the socket.

 

[CWatters]

My question is :what is the role of neutral conductor in the 230v European single-phase system .My assumption how it works that a neutral conductor serves to close the circuit between phases and to carry the imbalance current between different phases If all the phases are balanced then the neutral conductor does not caries the current but closes the circuit between different phases .?

Houses are fed a single phase so all the load current appears on the neutral. However my understanding is they try and balance the load across the three phases by arranging for roughly the same number of houses to be on each phase.

There are several different earthing strategies but typically Neutral and Earth are connected together somewhere locally (Either at local transformer or at the house).