Zappi includes a built-in function to protect the grid supply from an overload. If the current measured by the grid current transformer (CT) exceeds the limit that has been set when the zappi was commissioned then zappi will limit the output to the electric vehicle (EV) to prevent the fuse blowing.
By default the grid limit is turned off but, by setting a suitable limit to match the rating of the distribution supply fuse it is possible to install zappi without having to have the electricity supply upgraded.
This feature works whether the Grid CT’s are connected directly to the zappi or over a harvi wireless link
It is recommended that the Grid CT’s are wired to the zappi if there are any concerns about the reliability of the wireless link. The Distribution Network Operator (DNO) may insist that the CT’s are hardwired.
With a wired CT, the zappi includes an additional protective feature which will turn off the output if the zappi detects that the CT has become disconnected. Full details are included in this document which may be provided to the DNO if requested.
How does the Grid Limit work?
This short video explains…