Solar PV Panels

penrhyn

Were you running any appliances?

zeupater

JenR8 wrote: »

I wonder if any of the 'Techies' on these threads can explain this:

I have a new (rent a roof) installation, and my leccy meter is running backwards so I know when I'm generating. Yesterday, in the middle of the day when the sun was blazing, my system stopped generating and we were using. Hubby went up in the loft to look at the inverter, which had lights flashing and was turning itself on and off continually. Some while later the system started to generate again.
We have a 3840Wp system with a Fronius IG35 Inverter.
What do you think?

Hi

As penrhyn mentioned, you could have just been using more than you were generating.

If this was not the case, I believe that the IG35 detects errors it will display error codes which will help troubleshoot. If this happens again you should note what error code is displayed.

A total guess is that the grid conditions were problematic for a while in your area, possibly overvoltage or similar which was preventing your inverter from connecting to the grid .... but as stated, this would be a total guess .... have you looked at what the connected AC voltage is to see whether you generally have high voltage conditions ??

I'd simply ring the 'rent-a-roof' provider and tell them that they lost out on FiTs on a bright & sunny day ..... they'll probably be around to check this out PDQ.

HTH
Z

John_Pierpoint

The inverter works by making alternating current at a higher voltage than offered by the grid . So the PV electricity flows backwards into the grid.

Does it follow that if a group of houses, sharing the same feed from the grid, all install PV panels, their inverters could over supply the local network and thus by competing with each other lock out some home's inverters?

zeupater

John_Pierpoint wrote: »

The inverter works by making alternating current at a higher voltage than offered by the grid . So the PV electricity flows backwards into the grid.

Does it follow that if a group of houses, sharing the same feed from the grid, all install PV panels, their inverters could over supply the local network and thus by competing with each other lock out some home's inverters?

Hi John

The grid should be operating at a nominal 230V with a set +- tolerance, however most areas areas operate at a much higher voltage as standard, with this fluctuating throughout the day. My mains supply seems to operate/peak at over 250v quite regularly. As you mention, inverters inject power back into the grid at a slightly higher voltage than what the grid is providing, however, the inverter will have a setting to prevent export if the voltage would need to be higher than the grid voltage upper tolerance limit and should cut out until grid conditions improve. As mentioned, this is only a possibility.

Regarding large groups of arrays in an area, if this becomes an issue the DNOs will likely restrict further installations until they can modify/upgrade the local network. I believe that this very issue is causing headaches to grid operators in Germany .... for example http://www.powergenworldwide.com/index/display/articledisplay/4622417585/articles/power-engineering-international/volume-18/issue-10/regulars/analysis/too-much-to-handle-germanys-solar-power-plan-takes-it-toll.html

HTH
Z

John_Pierpoint

I have been reviewing energy saving measure again this year.

A new favourite has appeared amongst the "green" fraternity - some sort of gizmo to stop the consumer having to pay extra for super voltage electricity. For those old enough to remember this must be a bit like being forced to buy 5 star petrol at the pump when most cars ran on 4 star or even two star.

Can anyone point at a laymans explanation of how it works and what it costs and does it make financial sense to install such a gizmo?

penrhyn

It works by reducing the voltage fed around your property.
So your lights will be a little dimmer.
It apparently works best for motorised appliances, fridges circulation pumps etc.

Not much use for the electric kettle /heating appliances for obvious reasons.
http://www.vphase.co.uk/

Another great example of greenwash.

JenR8

Thankyou for your feedback. We were not using any appliances, and the meter goes backwards during all daylight conditions usually when no appliances are being used. It had been whizzing backwards shortly before and weather conditions were ideal for generating lots! I have notified our 'R-a-R' company, and we are going to be monitoring what happens on other sunny days when we are at home in the middle of the day. However I get the impression that their remote monitoring only picks up total generation, not what is generated at any particular time. My husband wondered if the inverter was being overloaded? Which would be bad news in the middle of the day in March!

Cardew

John_Pierpoint wrote: »

I have been reviewing energy saving measure again this year.

A new favourite has appeared amongst the "green" fraternity - some sort of gizmo to stop the consumer having to pay extra for super voltage electricity. For those old enough to remember this must be a bit like being forced to buy 5 star petrol at the pump when most cars ran on 4 star or even two star.

Can anyone point at a laymans explanation of how it works and what it costs and does it make financial sense to install such a gizmo?

As said above, a complicated and expensive to fit, device that reduces voltage in a property.

Whilst it works - particularly for electrical motors - it is very difficult to quantify savings in a domestic dwelling; IMO it will not make financial sense for most of us.

More use if you have scores of fridges and freezers like big supermarkets.

John_Pierpoint

I wonder what it would do when fed "backwards" high voltage electricity from the PV panels inverter?

[Deleted User]

sounds like a fault. Our fronius runs quietly with a green light all day every day and there is a red light when no electricity is being produced. It should not have been turning itself on and off. I hope the loft is nice and airy as the fronius also generates quite an amount of heat when working at high capacity and it needs to be cooled