Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Suggested Answer
  • Replies 21 replies
  • Helpful Answers 1 Helpful answer
  • Subscribers 38 subscribers
  • Views 478 views
  • Users 0 members are here
Options
You may also be interested in

Domestic EESS, island mode and island mode isolator

Downdraft

Hello,
I need some help please Slight smile

I am trying to understand if an 'Island mode' isolator is required for this particular inverter design.

The Solar PV Hybrid inverter has an 'EPS' (emergency power supply) output that we would like to use.
The inverter has an internal N-PE Bond relay.
In connected mode this takes its power direct from the grid.
In island mode the Hybrid inverter will have disconnected from the grid as per G98/99, and then the EPS is supplied from PV and/or battery.

So if the inverter is designed to disconnect from the grid during grid loss/outside protection limits is either an Automatic or manual changeover switch required?

Parents
  • 0

    Hello,
    The manufacturer has confirmed that they use relays and they shared this schematic:

  • 0 in reply to Downdraft
    AMK said:
    Is it a case of confirming the inverters relays are multipole (switching both phase and neutral), tested for low leakage currents (<5mA)  

    Contact gap also is important ... we are reliant on product standards for this ... relays don't appear in Table 537.4, and certainly in the past relay standards don't cover 'isolation' requirements. I'm not sure whether any relay standards have been, or are being, developed to address this.

  • 0 in reply to gkenyon

    So for a configured system where the inverter’s EPS setup powering a dedicated consumer unit, are we also required to install an external to the inverter, automatic, Line & N  island mode isolator on the inverter’s incoming side to ensure, auto disconnection of all live conductors during island mode, to comply with 826.1.1.1  and ESQCR Regulation 21? I can’t quite make out the image above, are both relays part on the inverter?

  • 0 in reply to AMK
    AMK said:
    So for a configured system where the inverter’s EPS setup powering a dedicated consumer unit, are we also required to install an external to the inverter, automatic, Line & N  island mode isolator on the inverter’s incoming side to ensure, auto disconnection of all live conductors during island mode, to comply with 826.1.1.1

    Only where the inverter, or kit of parts provided, doesn't include such a device. It's up to the manufacturer how they approach the issue.

    Other countries don't have ESQCR, and systems and legislation varies around the world ... even in Europe.

    In a global market, manufacturers may not be aware of UK legislation, although I agree they should investigate fully prior to coming to market (or, for importers, before importing to the UK ... or any other country for that matter).

    "Buyer beware".

  • 0 in reply to gkenyon

    So, purchasing a MCS registered inverter would likely meet UK-standards - 7671 & ESQCR for safe disconnection of live conductors (including neutral) no external device required for EPS mode

  • 0 in reply to AMK
    AMK said:
    So, purchasing a MCS registered inverter would likely meet UK-standards - 7671 & ESQCR for safe disconnection of live conductors (including neutral) no external device required for EPS mode

    You would have to ask MCS about their criteria, and whether it covers island mode capability.

Reply
  • 0 in reply to AMK
    AMK said:
    So, purchasing a MCS registered inverter would likely meet UK-standards - 7671 & ESQCR for safe disconnection of live conductors (including neutral) no external device required for EPS mode

    You would have to ask MCS about their criteria, and whether it covers island mode capability.

Children
No Data

Community Rules & Guidelines