SMA Technol ogie AG El ectrical Connection
Installation Guide SMC50A_60A-IEN073320 Page 35
2. Grid Impedance
Due to a high grid impedance, a high line resistance or a high voltage at the feed-
in point, a high AC voltage may result at the connection point of the Sunny Mini
Central. In Germany, the 10-minute average of the output voltage (Uac) of the
Sunny Mini Central is limited to 253 V according to DIN VDE 0126-1-1. If the
Sunny Mini Central records that the 10-minute average exceeds this voltage limit,
or if the 260 V limit is exceeded, it switches off immediately and displays a grid
error message. If voltage rise protection is not required in the relevant grid area
(outside Germany), it is deactivated by means of presetting the LDVtgC parameter
(see section 14.4 "Sunny Mini Central Operating Parameters" (Page 82)). In this
event, only the fast cut-off via the Uac-Max parameter intervenes.
The following diagram shows the power output the inverter can feed into the grid
per phase without leading to a switch-off because the AC voltage is too high.
The following variables are needed to make an estimate:
- Grid voltage without mains supply
- Grid impedance at the terminal of the Sunny Mini Central
Output [kW] per phase
Grid impedance [Ohm]