String fuses?

[wozzit99]

Hi

I'm getting confused about the use of string fuses.

In the dti guide 4 or more strings in parallel require string fuses to be used in the design of a system.

In certain sma inverters, for example the tri power tl8000 they already have string fuses built in. There are 4 d/c inputs on this inverter (input A) and 1 d/c input (Input B).

Using pv sol and the inverter above it specifies for the system to work correctly there should be 4 strings of 16 panels connected in parallel.

Do I have to connect the strings in parallel before the inverter therefore needing string fuses or do I take each set of strings back to the inverter where it sorts out the parllel conection inside and protects the strings with string fuses?

Wozzit

 

[JulianC]

Take each string back to the inverter. The 4 inputs on input A are basically paralleled with each other in the inverter so operationally it is the same as 4 paralleled strings on one input, but with the benefit of electronic string fusing.

 

[wozzit99]

Thanks Julian

 

[daytona600]

tripowers have string fuses with electronic monitoring built in
you can also fit class two arrestors for surge/overvoltage or external type 1&2 for lightning/surge/overvoltage
if you have say 4 strings connect to inverter inputs over the two mppt trackers
selecting highest number of modules per string for best inverter effciency
eg - use 4 x 1000vdc padlockable string isolators if dc cables are long

they need to be 1.1/1.25 overrated on voltage/current
or use one multi input string collection boxes / isolators with built in MC3/MC4/Sunclix connectors ( multicontact type iii or iv )
these are made from 2 to 48 strings with MC connectors incomers with MC or cable gland outgoing
class 1&2 arrestors can mount inside the isolators or multi string pv fireman switches with MC connectors with UVR for remote disconnection
quick simple tooless and plug & play


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