Connecting INCH charging stations to a three-phase grid without Neutral conductor
- Landis+Gyr – EV Editor 4
The neutral conductor (N-conductor) is present in the TN-S, TN-C-S, and TT distribution systems. In a TN-C distribution system, however, the N-conductor is combined with PE (ground) in the so-called PEN conductor. IT systems do not have an N-conductor, so the problem is in the IT distribution system itself.
If connecting an INCH charging station to a distribution system without an N- or PEN conductor, the solution is to install a 3-phase transformer (Dyn or Yyn), which would provide the point of the N-conductor.
If the load of the INCH (AD/DC converter in the car) is a single-phase, a 1-phase transformer with a voltage ratio of Np : Ns = 1.739 * can be used to reduce the phase-to-phase voltage from 400 V to 230 V, where one of the phases is connected to the N-terminal. This solution would be cheaper; however, we must ensure that the connection is always 1-phase.
* Np is the number of turns of the primary winding and Ns is the number of turns of the secondary winding on the transformer.
If the above procedures are done incorrectly or if an IT system without a transformer is used, the charging station will be damaged.
If you decide to use the options described above, it is necessary to first assess the given situation, design a solution, and carry out measurements. Only then the connections can be carried out.
Warning! Before installing, wiring, handling or accessing the charging station in any way, make sure to read, understand and follow the Safety Guidelines.
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