AC volt drop on pv system

[paulsamuel1984]

I am currently designing a 29kW system for installation on an agricultural barn.

The PV system will feed into a 3ph db in the barn. The exisitng db is fed from a 63A fuse switch, approx 50m away with a 16mm cable. The fuse switch is in turn fed from the DNO cabinet approx 100m away with a 35mm cable.

The volt drop of the new pv install is approx 0.08% but the overall volt drop to the DNO point of connection is 2.46% by my calculations.

I have spoke to the DNO and they advised to put a voltage recorder on the load end to see what the current volt drop is.

The DNO has adivsed that generally a 12V - 13V (-6%) is acceptable, I am currently at 6V volt drop.

Has anyone come accross this situation before, I know the DTI guide says 1%.

Do I need to upgrade one of the existing cables?

 

[BruceB]

2 issues:
- does it make economic sense to increase the size of the cable(s). Will you get your money back from less power loss.
- given local conditions and the likely voltage rise are you likely to hit voltage limits on inverters and get drop outs.

Beware DNOs talking about voltage drops; they do not normally mean within installations.

Regards
Bruce