Proposed wiring diagram
asked
Does Multiplus II disable Ground Relay automatically when Country/Grid code Australia AS/NZS4777.2:2015 (AC Neutral Path externally joined) is configured?
It is software disabled automatically in VE Config when the Australian grid code AS/NZS4777.2:2015 (AC Neutral Path Externally Joined) is selected.
That it is a ‘software solution ‘ is understood , how it physically achieves the desired ‘ wiring effect ‘ is not explained . This ‘patch ‘ was introduced from firmware xxx466 onwards to address a ‘ reconnection to grid after a LOM ‘ issue with Multiplus 11s’ in particular ( if I recall correctly ?)The question here ( unless I am mistaken ?) is - - how ‘literally‘ was it achieved , and Is any extra external reconfiguring ( fuse box ) required to make usage of this ‘patch’ legal .
For Australia I have no idea. Where we are the ground relay is disabled in software. But we have neutral/earth bound at the mcb before the inverter, and the main house ground/earthing rod there as well. No grid feedback at all allowed here.
For some installations the ground relay can be problematic. Especially if there are items in the house wiring that cause earth neutral leakage, or an earth point downstream of the inverter. Some light dimmers and faulty geyser elements can cause headaches, to name a few, you can tear your hair out finding the causes of the ground relay test faliure.
In Australia for grid connection ,the inverter has a N/E connection either side of the inverter , hence connected neutrals , this is unavoidable - so with ’earth leakage‘ issues and the possibility of grid voltages outside of comfortable parameters , the chances of ’reconnecting with the grid ‘issues are bountiful . Victron firmware ‘fix’ is not very specific on - how it is achieved - and how to safely adapt it to ones own circumstances .
How’s this for a fix - there would be a time delay involved ( to be determined ) but would negate all the above issues - - please feel free to ‘pick the c..p out of me .
1. Multi’s programable relay - grid on ACin triggered for xx secs
2. Appropriate multi pole contactor NC on inverter ACout - to disconnect all the above ‘Issues’
3. Inverter , now ‘issue free‘ to reconnect to grid .
4. Inverter now ( time delay expired ) reconnects to load .
To confirm the answer to the original question,
The GND Relay is automatically disabled when any “AC Neutral Path externally joined” grid code is chosen.
In that case, the Inverter/charger will NOT make a connection between N-Out and GND.
This should be used when there is a hard wired Earth Neutral link on the AC input side, or the AC output side, and the AC input and AC output Neutrals are linked together.
In this case even if the grid is disconnected, and both Active and Neutral are isolated inside the Multi, the Neutral to Earth link remains intact via a path OUTSIDE the Multi.
The alternative case is where the AC input neutrals and AC output neutrals are physically separated and not connected. Then when the Multi disconnects from the grid the Active and Neutral are isolated, and the Earth to Neutral link on the input is then disconnected from the Neutral on the output.
This then requires the alternative grid code (AC Neutral Path not externally joined), and the ground relay will be enabled and closed when the grid is disconnected, making the connection between Neutral and Earth for the operation of RCDs.
Installations with multiple hardwired links to Neutral and Earth, or multiple earth reference points are going to have earth differentials through the system and nuisance RCD tripping with or without the Multi.
As is written in the Australian Standards, the system designer and then the installer is ultimately responsible and will need to understand equipment behaviour and the specific onsite limitations for each site for a safe and successful installation.
When I choose "Australia Externally joined" ESS Assist does not work properly. It does not use batteries to power the house, uses only grid and mppt recharges the battery up to 100% SOC. Why ?
Could be many reasons, best to ask in a new question. Please create one specifically about this.
Does anybody have a circuit diagram for any of this?
Hi,
Countries without the option "AC Neutral Path externally joined" like Germany means that it's not allowed to join the neutral path?
Thanks
