vac problem

dave992 · Apr 19, 2013

hi, im an electrician but haven't done my solar qul or never installed solar equipment,i still live with the parents but my dad had a solar system installed but when the inverter working nearly flat out was have a error come up saying VAC failure, then the inverter turns off and take time to restart. The inverter is a ever solar inverter, any help would be good.

thanks dave

dansk · Apr 19, 2013

Voltage AC problem, either grid is too high or inverter isn't set for UK

Earthstore · Apr 19, 2013

Or the old chestnut, AC cable too small.
If you are a sparky, do the VD calc and post what it is in %.

dave992 · Apr 19, 2013

hi thanks for the reply, the company installed the solar equipment. with guard the voltage different the company have use voltage optimiser to control the voltage range, should this control the vac problem.

dansk · Apr 19, 2013

Not if done correctly as PVshould be connected before VO unit.

Check the inverter is set to G83 UK, power down the unit then power up and look at the screen it should tell you,if not take a note of the serial number and post in here that will.

dave992 · Apr 19, 2013

Hi earthstore, i haven't done the calculation because im not sure if it a different formula. It a 80m run, 4 kw system and in 3 core swa buried in the ground, some could help me would be good.

thanks

dave992 · Apr 19, 2013

hi dansk, the v/o is place on the incoming tails, this is the one we got Eversol TL4000. Thanks for your help

dansk · Apr 19, 2013

VO isn't my bag, but as I understand it PV shouldn't be connected the VO unit, I'm sure someone on here will know for sure.

i haven't done the VD calc, for yours, but last 80m ish run I did was in 16mm.

dansk · Apr 19, 2013

Also FYI most inverters are manufactured for a global market and sometimes the settings aren't set for the uk and therefore other country's voltage range canbe stricter than ours. for example I fixed a system the other week, omnik invert which is same as ever solar and that was set to NL (holland) top voltage range was 250, incoming grid was already high at 247 so when the system was generating good levels it didn't have much scope for movement in terms of voltage.

dave992 · Apr 19, 2013

Dansk thank you for all this help, just wanted to clarify a little with guard the cable cac, solar panels wires come off the roof straight into to interver then travel 80 m back to th hose and db board, how would I know if the inverter was set up correctly? Thanks

dansk · Apr 19, 2013

as post #5

the chances are its ok and it could be as earth store said about VD and incoming voltage etc.

Earthstore · Apr 20, 2013

dave992 said:
hi thanks for the reply, the company installed the solar equipment. with guard the voltage different the company have use voltage optimiser to control the voltage range, should this control the vac problem.

No.

There could be several reasons why this is happening, my first question is who installed it and have you spoken to them yet? (Oh that's two questions)

What size is your PV system? What size is the SWA cable? What make of VO have they installed? How and where have they connected the PV to your supply? Is it before or after VO, on shared RCD.

A good pic is quite often worth a thousand words.

dave992 · Apr 21, 2013

Try and do my best describe to installation, So we have two systems on the same roof, both 4 kw systems, comes off the roof straight into the inverter, Then from the inverter we have one system going to the house and seconded system going to the farm. From the inverter we have a length of 80 m and from the inverter to the farm a length of 100 meters. Both are wired in 10 mm 3 core swa cable and are both on 32 amp breaker. They have placed a voltage optimer between the both DB and the incoming tails. Tried my best and question please ask.

We have a ever solar tl4000 inverter
Voltage optimer is a vphase one

Want to say again very grateful for any help.