PV Inverter cutting off array sunny days

[RonanIrl]

looking back at the last time this happened see the voltage RUA (not sure what this is though) seems it’s lower than the input voltage I get of approx 235v perhaps the issue is here.

03_Rev02_NA.pdf[/URL]


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very interesting article I did note a slight voltage increase on the grid last week on a sunny day it was up at 238-240 (normally 235 stable) but the location of other solar installations nearby are minimal as noted above. When the engineer is here next week I’m going to ask him to also check the size of the cables from consumer unit to meter and meter to transformer if possible and let you know the size and length.
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[marconi]

Thank you. I will ponder more on the plots. R,S,T or U,V,W or A,B,C identify which phase the voltage refers to. In your case the inverter and your home is single phase which means only voltage for one phase, phase one or R,U,A is measured. I don't think for now solar voltage rise is the problem.

The dc voltage plot clearly shows (but see my PM to you) the voltage dropping from 200 odd volts to near zero volts - this could happen if the shunt relay opens. The dc voltage plot also looks erratic but that may be the time scale selected for the plot. For the shunt relay to remain closed it requires ac power to be available on the supply side of the left hand lockable ac isolator shown in the schematic of your installation in #11. You could ask the electrician who visits on Friday to check thoroughly all the ac connections between the inverter ac output right back to and including where it connects to the incoming mains in case there is an intermittent open circuit perhaps caused by poor contact or a deteriorated contact and similarly between the shunt relay and the ac isolator - which is/are only apparent when high ac currents are flowing eg: high export/backflow power. While he is present he should also check the dc connections to the array and battery.

Could you also look at section 5.5.10 on EPM settings (Electronic Power Management) and tell what settings have been selected:

https://static.solartricity.ie/wp-content/uploads/2018/04/Solis-Hybrid-Inverter-Manual.pdf

I want to establish what priorities have been selected for the use of pv power, battery power, export/backflow power.

 

[marconi]

Do your home lights ever flicker on and off? Or dim/swell in brightness for a few seconds?

 

[marconi]

RonanIrl: Thank you for the access to your solar PV system which I am studying. Could you confirm a couple of things for me please?

1. You have a generation meter in the ac line from the inverter to the mains intake which does indeed clock up kWh?
2. Do you have a 'current clamp' attached around one of the electricity supplier's meter cables? It will look something like this:

Learn | OpenEnergyMonitor - https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/installation

It will be hard-wired back to the inverter or connected via a radio signal eg: Wifi.

3. On your electricity bill is the debit amount of electrical energy you have to pay for the difference between your electricity supplier meter reading and your pv generation meter reading?

4. On your bill is their a separate credit for surplus energy you have exported to the grid at a different rate to the units in para 3 - I wager there is not.

Its appears to me that your pv system is set up to optimise 'self-consumption' of solar energy in real-time and if that cannot be achieved ie: your home's load is lower in kW than that being produced at the time by the panels to then store the excess in the battery for use at other times.

Because your backflow(ie: net )export power setting has been set to zero kW I think (need to confirm by studying more plots) that your system will never ever export solar panel power in excess of what can be consumed in real-time. So if your home load was say 1kW and the panel was producing 2.5kW and the inverter would offset the 1kW for the home load so there was no draw from the grid: and the excess of 1.5kW would be used to charge the battery. If the home load reduced to 0 kW the inverter would stop feeding 1 kW into the grid and the full 2.5kW would be used to charge the battery. However, once the battery is at 100% SOC any excess solar energy can no longer be stored in it; thus there can be the situation that there is no/next to no home load, high solar pv generation topping up the battery, the battery becomes full and all solar pv generation is terminated and the array current is deliberately reduced to zero Amps - or in other words pv generation ceases. It ceases because there is no where for it to be stored or consumed in the home and true export to the grid is forbidden by the backflow setting of +0000W. This is the 'self consumption' priority scheme.

To export surplus pv energy which you cannot store or consume in your home the scheme would have to be 'prioritise self-consumption and export/sell surplus'.

See for more explanation - you have the first set-up I reckon ;total self consumption any 'sale of excess' is prohibited at the moment by the backflow power being set at +0000W - you do have a generation meter for the reasons in para 3 above:

https://news.dualsun.com/news/lets-talk-about-pv-self-consumption/#:~:text=With%20%E2%80%9Cself%2Dconsumption%E2%80%9D%2C,meet%20the%20home's%20electricity%20needs.

This thinking - if correct - indicates why there have been no fault codes or alarms - it is the current mode of operation of your system for using and storing pv energy to minimise your import of electricity from the grid.- but to make no gain from selling any excess
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If you log in, go to Devices, click on the blue tick beside your inverter and then open the 'Status' you will see that 'Self-use mode' aka 'Self-consumption has been selected.

 

[RonanIrl]

See my comments below thanks

RonanIrl: Thank you for the access to your solar PV system which I am studying. Could you confirm a couple of things for me please?

1. You have a generation meter in the ac line from the inverter to the mains intake which does indeed clock up kWh?
Yes ther is a meter in my Consumer unit that seems to just total generation since day one

2. Do you have a 'current clamp' attached around one of the electricity supplier's meter cables? It will look something like this:

Learn | OpenEnergyMonitor - https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/installation

It will be hard-wired back to the inverter or connected via a radio signal eg: Wifi.

I dont see one in the meter cabinet unles it is hidden away somwhere in the system betwene the meter cabinet and conumer cabinet possibly in the attic, im sure it is illegal to place anything in the meter cabinet on the network side of the meter as it owned by the network supplier

3. On your electricity bill is the debit amount of electrical energy you have to pay for the difference between your electricity supplier meter reading and your pv generation meter reading?

Not appicable as in Ireland we still dont get paid for surplus and no smart meters are installed yet..seems they are mandatory per EU law in 2021

4. On your bill is their a separate credit for surplus energy you have exported to the grid at a different rate to the units in para 3 - I wager there is not.

As above NA

Its appears to me that your pv system is set up to optimise 'self-consumption' of solar energy in real-time and if that cannot be achieved ie: your home's load is lower in kW than that being produced at the time by the panels to then store the excess in the battery for use at other times.

Because your backflow(ie: net )export power setting has been set to zero kW I think (need to confirm by studying more plots) that your system will never ever export solar panel power in excess of what can be consumed in real-time. So if your home load was say 1kW and the panel was producing 2.5kW and the inverter would offset the 1kW for the home load so there was no draw from the grid: and the excess of 1.5kW would be used to charge the battery. If the home load reduced to 0 kW the inverter would stop feeding 1 kW into the grid and the full 2.5kW would be used to charge the battery. However, once the battery is at 100% SOC any excess solar energy can no longer be stored in it; thus there can be the situation that there is no/next to no home load, high solar pv generation topping up the battery, the battery becomes full and all solar pv generation is terminated and the array current is deliberately reduced to zero Amps - or in other words pv generation ceases. It ceases because there is no where for it to be stored or consumed in the home and true export to the grid is forbidden by the backflow setting of +0000W. This is the 'self consumption' priority scheme.

Do i need to adjust the backflow setting?? if so what value?

To export surplus pv energy which you cannot store or consume in your home the scheme would have to be 'prioritise self-consumption and export/sell surplus'.

See for more explanation - you have the first set-up I reckon ;total self consumption any 'sale of excess' is prohibited at the moment by the backflow power being set at +0000W - you do have a generation meter for the reasons in para 3 above:

https://news.dualsun.com/news/lets-talk-about-pv-self-consumption/#:~:text=With%20%E2%80%9Cself%2Dconsumption%E2%80%9D%2C,meet%20the%20home's%20electricity%20needs.

Ok so that makes sense to me but i see power being exported all the time on my app for example today I was generating 5.23, battery was full 7KW and house only using 330W, eddi hot water heater was off as desired temp was met so rest was showing as flowing back into the network. If this was the case I wuld be getting faults alonmst daily in summer as my house has a very low load of 330W and high generation of 6.3KW max =-5%.

How do i change form self use to prioritise self-consumption and export/sell surplus' as you note above

Today was a great example it was super sunny loads of power, full battery, low house load and no heating water load and the system didnt switch off..seems to be heat related as the system will turn off if its also a warm day yet no alert codes on the inverter, maybe the installer is correct they are thinking the shunt is malfuctioning (switches off at over 70 degrees interbal temp) in the attic and shutting down hence sutting off grid access for power to escape. Attic owuld not have been more than 26 today but im guesisng can get higher in summr so that coupled with an inetrnal fault on the shunt could be the problem but im not sure.

This thinking - if correct - indicates why there have been no fault codes or alarms - it is the current mode of operation of your system for using and storing pv energy to minimise your import of electricity from the grid.- but to make no gain from selling any excess
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If you log in, go to Devices, click on the blue tick beside your inverter and then open the 'Status' you will see that 'Self-use mode' aka 'Self-consumption has been selected.

Is there any setting i need to change here I want to use power when the house, water, battery need it and once battery is full and house/water satisfied then export to grid so in future i get paif for excess (when the buy back system finally come on stream in Ireland)

 

[marconi]

See my comments below thanks



Is there any setting i need to change here I want to use power when the house, water, battery need it and once battery is full and house/water satisfied then export to grid so in future i get paif for excess (when the buy back system finally come on stream in Ireland)

I will read your reply above tomorrow. Meanwhile:

I cannot access the EPM settings options - perhaps you can and then relay them to me.

I also need to know the battery charge/storage option which has currently been selected - they are off-grid, auto or timed.

The Backflow power would need to be increased to a setting allowed in Ireland.

You'd need to confirm with your electricity supplier they will indeed pay for your excess or change to a supplier who will - not sure if you have several energy suppliers or a nationwide one.

You made need your system to be certificated by your installer or your electricity supplier if you want them to pay for your exports - I don't know what is required in Ireland. In UK payments for exports in the domestic setting are pittance - far better to self-consume, store or offset.
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[RonanIrl]

Marconi in ireland it’s not an option to sell or offset excess yet.. I know crazy in this day and age but they are supposed to work towards it for end of 2021 with smart meters being installed etc. The system is fully certified etc already but I’m an early adopter in Ireland very few houses nationwide with PV arrays. I’m also going with a Tesla next year hence why I want to be sure the system is working as well as possible.
Can you tell me what you need regards EPM settings I’m not sure what you mean.

battery is set to timed but time settings are not input so it charges and discharges 24hours a day.

Also I’m adding below an image showing the settings for ireland Per the inverter. Note the down times for voltage over etc are only 40 seconds so seems to indicate this issue is either outside the inverter or the rules are being broken continuously for long lengths of time when the system goes down.

[

also see today’s status with battery full house drainage very little and export occurring on a sunny day.

QUOTE="marconi, post: 1657802, member: 87486"]
I will read your reply above tomorrow. Meanwhile:

I cannot access the EPM settings options - perhaps you can and then relay them to me.

I also need to know the battery charge/storage option which has currently been selected - they are off-grid, auto or timed.

The Backflow power would need to be increased to a setting allowed in Ireland.

You'd need to confirm with your electricity supplier they will indeed pay for your excess or change to a supplier who will - not sure if you have several energy suppliers or a nationwide one.

You made need your system to be certificated by your installer or your electricity supplier if you want them to pay for your exports - I don't know what is required in Ireland. In UK payments for exports in the domestic setting are pittance - far better to self-consume, store or offset.
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[RonanIrl]

No lights never flicker.

I also upgraded my supply from 11-16 KVA supply a few weeks back wondering if that could help the issue but no idea If it makes any difference.


QUOTE="marconi, post: 1657722, member: 87486"]
Do your home lights ever flicker on and off? Or dim/swell in brightness for a few seconds?
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[marconi]

Could you give me some other days when the inverter stopped generating power please - what I have noticed is that if one looks at inverter internal temperature and dc voltage pv1 against time for the 18 Aug 20, the drop in pv1 voltage co-incides with the inverter internal temperature reaching 59.8C. There is this notice under the 'Temp' tab the bold, underlined italicised text is relevant:

--->
IGBT (Core) Temperature
When IGBT temperature is lower than its max. tolerance temperature, inverter can run stably.

Inverter Ambient Temperature
Inverter internal air temperature

Notice: Usually, IGBT temperature is 20 ℃-30 ℃ higher than inverter ambient temperature.
<---

So, maybe at maximum generation, on a hot day in your loft the IGBT(Core) temperature is of the order 59.8 + 30 = 90C. All semiconductors ( in this case an Insulated Gate Bipolar Junction Transistor IGBT) have maximum junction temperature limits of the order 150C-175C. Normally the semiconductor devices are operated at temperatures much lower than the maximum in order to safeguard their reliability and lifetime. See: First few paras of:

https://www.analog.com/media/en/training-seminars/tutorials/mt-093.pdf

There will necessarily be a thermal gradient between the junction of the IGBT (a semiconductor power switch necessary for the conversion of dc into ac) and the the ambient air flowing of the heat sink of the inverter box. It may be then that at on very sunny days, with high ambient temperature in the loft and peak pv power generation the IGBT core temperature has been exceeded causing a shutdown of generation.

Have a look at the plot for 18 Sep 20 of DC voltage PV1, Ac Output Total Power and internal temperature C against time. You will note a period of very high pv generation (6.3kW) before the shutdown and a steady rise in temperature. The generation starts again when the internal temperature is 40C. The generation does not look stable, fluctuating markedly, which seems odd to me on a clear very sunny day without clouds. Could you post this plot for others to look at who may be following this thread - I cannot do it for some reason.

Anyway, to pursue this line of analysis I need some other times/days when the inverter shutdown to see if the same correlation is apparent.

 

[marconi]

https://voltaconsolar.com/DOWNLOAD-FILES/Solis/Solis-RHI-(3-5K)_Installation Manual Voltacon.pdf

1. Re: Fig 3.3 - Meter Communication socket - Is anything connected to this socket?

2. Re: Your # 37 - the power figures do not balance. Power in from solar and battery is 5.6kW and power out for consumption and export to grid is 5.16kW - a difference of 0.44kW being apparently dissipated as heat in the inverter box - if the readings are correct. Rather a lot of thermal heating inside the inverter box.

3. It appears from the power figures that at least one of the grid power or consumption powers is being measured in order that the other can be recorded. Maybe the consumed power is being measured by a current clamp and not the export grid power. Could you have a look around the consumer unit for a clamp - no need to open it up. It would be helpful if you took some photos and post them for me to look at of your loft inverter installation, your supply metering, inverter metering and consumer unit being careful to capture the cable routes and switchgear. And also for the data logger.

 

[marconi]

RonanIrl: I found this installation video:

RHI-(3-5)K-48ES - https://solisinverters.com.au/product/rhi-3-5k-48es/

Could you look at it and tell me any similarities or differences? At the moment I am particularly interested in the bits at 5min08s on the data stick (-do you have one?) and from 5min15s onwards on the meter and current clamp.

This is also interesting on how the Solis hybrid inverter reduces its power output at the temperature rises:

Inverter Temperature De-rating - https://usservice.ginlong.com/support/solutions/articles/36000074739-inverter-temperature-de-rating

You will see a table which says that the inverter degrades in power and then shuts down at 60C. Food for thought. But you do not it seems get an OV TEMP fault code or alarm which is perplexing.

I note your inverter, at least beneath it, does not have the minimum 300mm clearance and there is what looks like pyramid loft insulation.

PS: I declare now: if it was my installation, it would not be in the loft.

 

[Wilko]

Power in from solar and battery is 5.6kW and power out for consumption and export to grid is 5.16kW - a difference of 0.44kW being apparently dissipated as heat in the inverter box

Hello M - just triggered me on the conversion efficiency of the Invertor. For sure no Invertor is 100% efficient and these readings imply 1- 44/560 = 92%. So 8% in heat, hmmm ... smoking gun?

 

[RonanIrl]

See below answers


Could you give me some other days when the inverter stopped generating power please -

May 30
June 2/16/19

what I have noticed is that if one looks at inverter internal temperature and dc voltage pv1 against time for the 18 Aug 20, the drop in pv1 voltage co-incides with the inverter internal temperature reaching 59.8C. There is this notice under the 'Temp' tab the bold, underlined italicised text is relevant:

--->
IGBT (Core) Temperature
When IGBT temperature is lower than its max. tolerance temperature, inverter can run stably.

Inverter Ambient Temperature
Inverter internal air temperature

Notice: Usually, IGBT temperature is 20 ℃-30 ℃ higher than inverter ambient temperature.
<---

So, maybe at maximum generation, on a hot day in your loft the IGBT(Core) temperature is of the order 59.8 + 30 = 90C. All semiconductors ( in this case an Insulated Gate Bipolar Junction Transistor IGBT) have maximum junction temperature limits of the order 150C-175C. Normally the semiconductor devices are operated at temperatures much lower than the maximum in order to safeguard their reliability and lifetime. See: First few paras of:

https://www.analog.com/media/en/training-seminars/tutorials/mt-093.pdf

There will necessarily be a thermal gradient between the junction of the IGBT (a semiconductor power switch necessary for the conversion of dc into ac) and the the ambient air flowing of the heat sink of the inverter box. It may be then that at on very sunny days, with high ambient temperature in the loft and peak pv power generation the IGBT core temperature has been exceeded causing a shutdown of generation.

Have a look at the plot for 18 Sep 20 of DC voltage PV1, Ac Output Total Power and internal temperature C against time. You will note a period of very high pv generation (6.3kW) before the shutdown and a steady rise in temperature. The generation starts again when the internal temperature is 40C. The generation does not look stable, fluctuating markedly, which seems odd to me on a clear very sunny day without clouds. Could you post this plot for others to look at who may be following this thread - I cannot do it for some reason.

The IGBT temp is a new measurement in the last firmware and SOLIS have looked into this already for my issue it was same on the old inverter so its not that accoring to them. The invetrer livese in a dark cold plant room so termpertaure there is never above 20, ite well ventillated and no heat sources on warm days.

Anyway, to pursue this line of analysis I need some other times/days when the inverter shutdown to see if the same correlation is apparent.
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[RonanIrl]

See Responses Below

https://voltaconsolar.com/DOWNLOAD-FILES/Solis/Solis-RHI-(3-5K)_Installation Manual Voltacon.pdf

1. Re: Fig 3.3 - Meter Communication socket - Is anything connected to this socket?
Yes black plug heading off somehwre

2. Re: Your # 37 - the power figures do not balance. Power in from solar and battery is 5.6kW and power out for consumption and export to grid is 5.16kW - a difference of 0.44kW being apparently dissipated as heat in the inverter box - if the readings are correct. Rather a lot of thermal heating inside the inverter box.

Dont owrry about that i had the backup meter swithed off in options ithis includes heat energy, internal energy to run the inveter and engery diverted to a second backup battery if instaleld, now I turned it back on the figures balance I actually had my installer on the blower about it last night and asked him why they didnt add up, once i enabled backup measurment again it did weird...id say he is sick of me by now.

3. It appears from the power figures that at least one of the grid power or consumption powers is being measured in order that the other can be recorded. Maybe the consumed power is being measured by a current clamp and not the export grid power. Could you have a look around the consumer unit for a clamp - no need to open it up. It would be helpful if you took some photos and post them for me to look at of your loft inverter installation, your supply metering, inverter metering and consumer unit being careful to capture the cable routes and switchgear. And also for the data logger.

At the moment im not in a position to acces the loft.. i do know there are clamps up there but could be anywhere on the long runs. Also gained this nugget of info on the call with the installer.

 

[RonanIrl]

Responses as below

RonanIrl: I found this installation video:

RHI-(3-5)K-48ES - https://solisinverters.com.au/product/rhi-3-5k-48es/

Could you look at it and tell me any similarities or differences? At the moment I am particularly interested in the bits at 5min08s on the data stick (-do you have one?) and from 5min15s onwards on the meter and current clamp.

Yes i have a data stick thats how the appa and webiste portal receive info via my wifi and firmware updates are deployed by SOLIS or me manually if sent.

Yes the meter is plugged in but clamp is up in the loft somwhere

The system is deifitly setup to know when grid is available and lines are clamped to measure

This is also interesting on how the Solis hybrid inverter reduces its power output at the temperature rises:

Inverter Temperature De-rating - https://usservice.ginlong.com/support/solutions/articles/36000074739-inverter-temperature-de-rating

You will see a table which says that the inverter degrades in power and then shuts down at 60C. Food for thought. But you do not it seems get an OV TEMP fault code or alarm which is perplexing.

Solis looked into this also and said its not the issue that said inverter hyper clipping was my initail though what could be causing this

Inverter clipping: How to maximize solar project value

Inverter clipping, or “inverter saturation,” occurs when DC power from a PV array exceeds an inverter’s maximum input rating.

www.solarpowerworldonline.com

I note your inverter, at least beneath it, does not have the minimum 300mm clearance and there is what looks like pyramid loft insulation.

Its actualy in a cold plant room dark side of the house, 1m from the ground Pyramids are sound proofing for my boiler which is in the same room but obviously off in summer. Sound pyramids give little insulation as they are open cell. Fault was happening well before the sound insulation was installed.

The air can circulate via vents an its always below 20 in there even in sumemr.

SOLSI and my installer have looke dat temperatrure and both came back as negative causing the issue.



PS: I declare now: if it was my installation, it would not be in the loft.
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