Hello,
In the course of planning together with my electrician (who is very open minded, but only has basic knowledge of the MPII) we are at the point of designing the "bypass switch" or disconnecting the MPII in the event of maintenance (3-phase MPII network in Austria/Lower Austria network).
Normally, a 1-0-2 changeover switch (or 2 pieces) is used, but these are planned for emergencies when there is no grid and always go over 0 (with interruption).
Now to my question, which I am currently stuck with my electrician:
3 switch disconnectors (1xAC-In = C, 1xAC-Out1 = B, 1xBypass = A) to enable and activate the bypass in normal operation (and only then) without interruption
Initial state: A = open, B = closed, C = closed
Switching Normal->Bypass:
close A. grid is also connected to the synchronized and connected AC-Out1. Can something happen here? According to our understanding, the phase-synchronized potential is already there, since PassThrough.
open B. Disconnect AC-Out1 from the house network and from the grid potential.
open C Disconnect from AC-In
Switching Bypass->Normal:
close C. Connect AC-In to grid potential. MPII recognizes network and synchronizes.
close B. Switching through from the synchronized AC-Out1 to the home network
open A
As I said: will not be used for switching in the event of a power failure; only in the event of MPII maintenance. The entire house is connected to AC-Out1.
What can happen? What are we missing?
Thanks!
Bernhard
