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Thread: Precautions for long run 400 VDC cabling?
face BY : James Cameron email (remove spam text)

On Mon, Aug 14, 2017 at 05:01:38PM +1000, James Cameron wrote:
> When cabling DC from a solar array back to an inverter charger, with
> increasing design distance, what are the precautions for the cable
> design?

Some specifications have been filled in, and a quotation received from
my designer.  I'm pleased with it.

The system is to consist of;

1.  photovoltaic array, 10 kW, as 36 modules in four series strings,
each module Voc 39.9V, peak power 300W, Isc 9.64A, so each string
359.1V at 9.64A, (Trina Honey M Plus TSM-DD05A, see references),

2.  DC cabling, four runs of 400V DC cable, to a maximum of 1% loss
(not yet sure why), and any necessary array earthing cables,

3.  two inverter/chargers, each with two DC MPP inputs, one battery
connector for a 48V nominal battery, one grid interconnect, and one
emergency power output, (SolaX X-hybrid E series SK-SU5000E, see

4.  two 10 kWh lithium-ion battery arrays, (LG Chem RESU10, see

5.  contactors for switching loads to emergency power output of

6.  current transformer monitored by the inverter/chargers to
minimise grid import and export.

My quick system diagram showing power limits;


Theory of operation; power from the photovoltaics (2.5 kW per string)
is taken by a maximum power point tracking input of an
inverter/charger, and depending on battery state of charge, policy,
and consumer loads, is delivered to either the battery (2.5 kW) or the
loads in synchronisation with the grid (4.6 kW).

When grid voltage collapse occurs, an inverter/charger will drive a
contactor to switch a set of loads to an emergency power output, which
will deliver up to 2 kW per inverter/charger.  Is specified to take up
to five seconds.


Trina Solar DD05A.08 - Data Sheet

Trina Solar DD05A.08 - Install Guide

SolaX X-hybrid E series SK-SU5000E - Data Sheet

SolaX X-hybrid E series SK-SU5000E - Install Guide

SolaX X-hybrid E series SK-SU5000E - with LG Chem battery Wiring Schematic

LG Chem RESU10 - Data Sheet

LG Chem RESU10 - Install Guide

-- James Cameron
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<20170905020100.GA7430@us.netrek.org> quoted-printable

In reply to: <20170814070138.GB23379@us.netrek.org>
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