Home |
Search |
Today's Posts |
|
UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel?
One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). Are mirrors involved? TIA |
#2
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
jim wrote:
Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). Are mirrors involved? It's all low impedance connections, so you need quite a large current change to make a noticeable difference in the suply voltage. Anything other than incandescent light bulbs or very old, non-stabilised power supplies for TV sets won't really notice less than about a 10% change in voltage anyway, which should need a current change of 100 amps or moreif all is in order. As most domestic PV panel sets can't generate more than about 16A, it's not a problem. -- Tciao for Now! John. |
#3
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 22/09/2013 16:38, jim wrote:
Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). The potential difference required actually comes from a phase shift in the locally generated component. Depending on whether its leading or lagging the waveform supplied via the grid as to whether its drawing or feeding current. The RMS voltages of both grid and the output of the local inverter could actually be the same. The local grid tie inverter will adjust its generated phase relative to the grid voltage to achieve the required direction of energy transfer. Are mirrors involved? Not usually, and hopefully no smoke either ;-) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#4
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Sun, 22 Sep 2013 08:38:38 -0700 (PDT), jim wrote:
One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). The volts do change but not enough to notice. The voltage here drops by about 8 V when the E7 kicks in and 11 kW is instantly applied. A domestic PV array in bright sunlight produces less than 4 kW, only a bit above a rapid boil kettle... Do your lights flicker when you switch on the kettle? We don't notice the E7 coming on but then we don't have incandescent lights that would show it far more than anything else. -- Cheers Dave. |
#5
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Sunday 22 September 2013 16:38 jim wrote in uk.d-i-y:
Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). Are mirrors involved? TIA Yes, there is a PD, probably in the form of a very slight phase lead/lag. It is minute. The supply impedance will be less than 0.35ohms (L-N) so 10A FIT feed would be 3.5V or an equivalent phase shift. Not enough to be flickering lights. -- Tim Watts Personal Blog: http://squiddy.blog.dionic.net/ http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage Reading this on the web? See: http://wiki.diyfaq.org.uk/index.php?title=Usenet |
#6
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"John Rumm" wrote in message o.uk... On 22/09/2013 16:38, jim wrote: Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). The potential difference required actually comes from a phase shift in the locally generated component. Depending on whether its leading or lagging the waveform supplied via the grid as to whether its drawing or feeding current. The RMS voltages of both grid and the output of the local inverter could actually be the same. The local grid tie inverter will adjust its generated phase relative to the grid voltage to achieve the required direction of energy transfer. What are you rambling on about? The previous poster is entirely correct. As the power output from PVpanels increases, the voltage at the AC output terminal of the inverter rises. So "stuffing the electricity back down the spout " so to speak. My PV panels causes a rise of around 5volts when on full power. There is no phase shift, the power factor is around unity at all outputs, there is no transformer. |
#7
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 22/09/13 16:38, jim wrote:
Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). Are mirrors involved? smoke, and mirrors. :-) however the imdeance of the mains supply is pretty low... TIA -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
#8
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"jim" wrote in message ... Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). Are mirrors involved? You take say four Kw out of the system and the voltage drops by a small amount. You stuff four Kw back into the sytem and the voltage rises by the same amount. (Everything else being equal). Most of the energy stuffed back intot the sytem is used by nieghbours so in fact reducing the load on the system and making it more efficient. As long as the PV systems are small sytems, dispersed and there are not too many of them there are no problems. Large system can present problems and as they become common the problems will increase. This is another possible use for smart meters, the remote control of such systems. |
#9
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
Far more of an issue is synchronising the frequencies and putting crap on
the local supply or even creating RFI from the inverter in my experience, which is not much here, but from those who rushed out and got it, there have been issues.. grin. Brian -- From the Sofa of Brian Gaff Reply address is active "John Williamson" wrote in message ... jim wrote: Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). Are mirrors involved? It's all low impedance connections, so you need quite a large current change to make a noticeable difference in the suply voltage. Anything other than incandescent light bulbs or very old, non-stabilised power supplies for TV sets won't really notice less than about a 10% change in voltage anyway, which should need a current change of 100 amps or moreif all is in order. As most domestic PV panel sets can't generate more than about 16A, it's not a problem. -- Tciao for Now! John. |
#10
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
Of course a lot of these devices waste power when not a lot is being
generated, and over time I'd suspect this adds up to quite a high amount. 5v is nothing, in any day the mains goes up and down far more than that amount. Brian -- From the Sofa of Brian Gaff Reply address is active "harryagain" wrote in message ... "John Rumm" wrote in message o.uk... On 22/09/2013 16:38, jim wrote: Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel? One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). The potential difference required actually comes from a phase shift in the locally generated component. Depending on whether its leading or lagging the waveform supplied via the grid as to whether its drawing or feeding current. The RMS voltages of both grid and the output of the local inverter could actually be the same. The local grid tie inverter will adjust its generated phase relative to the grid voltage to achieve the required direction of energy transfer. What are you rambling on about? The previous poster is entirely correct. As the power output from PVpanels increases, the voltage at the AC output terminal of the inverter rises. So "stuffing the electricity back down the spout " so to speak. My PV panels causes a rise of around 5volts when on full power. There is no phase shift, the power factor is around unity at all outputs, there is no transformer. |
#11
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
In message o.uk, at
17:30:56 on Sun, 22 Sep 2013, Dave Liquorice remarked: A domestic PV array in bright sunlight produces less than 4 kW, only a bit above a rapid boil kettle... There's a big poster at my local Sainsbury's which says they generate enough electricity to boil every kettle in the town. But not simultaneously I suspect! And mine is a traditional one on gas hob, so that's a neat trick (maybe my share is the electricity to ignite the gas...) -- Roland Perry |
#12
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"Brian Gaff" wrote in message ... Of course a lot of these devices waste power when not a lot is being generated, and over time I'd suspect this adds up to quite a high amount. 5v is nothing, in any day the mains goes up and down far more than that amount. Brian The inverters in use these days are around 95% efficient. (No transformer) I think mine uses around 3w on standby. What are you rambling on about? The previous poster is entirely correct. As the power output from PVpanels increases, the voltage at the AC output terminal of the inverter rises. So "stuffing the electricity back down the spout " so to speak. My PV panels causes a rise of around 5volts when on full power. There is no phase shift, the power factor is around unity at all outputs, there is no transformer. |
#13
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 23/09/13 07:52, harryagain wrote:
"Brian Gaff" wrote in message ... Of course a lot of these devices waste power when not a lot is being generated, and over time I'd suspect this adds up to quite a high amount. 5v is nothing, in any day the mains goes up and down far more than that amount. Brian The inverters in use these days are around 95% efficient. (No transformer) I think mine uses around 3w on standby. Harry, the idiot who thnks inverters dont have any transformers. -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
#14
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
The Natural Philosopher wrote:
Harry, the idiot who thnks inverters dont have any transformers. Whilst the former is a matter of debate, a lot of the latest inverters have no transformer, like this: http://www.sma-uk.com/en_UK/products/solar-inverters/sunny-boy/sunny-boy-3000tl-3600tl-4000tl-5000tl-with-reactive-power-control.html "...the new transformerless Sunny Boy is the ideal solution..." Chris -- Chris J Dixon Nottingham UK Plant amazing Acers. |
#15
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 22/09/2013 18:07, harryagain wrote:
Most of the energy stuffed back intot the sytem is used by nieghbours so in fact reducing the load on the system and making it more efficient. Locally perhaps, nationally unlikely. The big generators can't be easily throttled up and down, and lose efficiency when this has to be done. Andy |
#16
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Mon, 23 Sep 2013 07:45:01 +0100, Roland Perry wrote:
A domestic PV array in bright sunlight produces less than 4 kW, only a bit above a rapid boil kettle... There's a big poster at my local Sainsbury's which says they generate enough electricity to boil every kettle in the town. But not simultaneously I suspect! Greenwash... if they are that proud of their solar PV why don't they have a big meter showing the total store consumption and what percentage of that is coming from the PV, both instantaneous and averaged over lets say a week. -- Cheers Dave. |
#17
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
In message o.uk, at
09:07:34 on Mon, 23 Sep 2013, Dave Liquorice remarked: A domestic PV array in bright sunlight produces less than 4 kW, only a bit above a rapid boil kettle... There's a big poster at my local Sainsbury's which says they generate enough electricity to boil every kettle in the town. But not simultaneously I suspect! Greenwash... Not the only example, they also say they are using LED lights in their (semi-underground) car park to save energy, but it's obvious they are fluorescents. if they are that proud of their solar PV why don't they have a big meter showing the total store consumption and what percentage of that is coming from the PV, both instantaneous and averaged over lets say a week. -- Roland Perry |
#18
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Monday, September 23, 2013 9:42:59 AM UTC+1, Roland Perry wrote:
In message o.uk, at 09:07:34 on Mon, 23 Sep 2013, Dave Liquorice remarked: There's a big poster at my local Sainsbury's which says they generate enough electricity to boil every kettle in the town. But not simultaneously I suspect! Greenwash... Not the only example, they also say they are using LED lights in their (semi-underground) car park to save energy, but it's obvious they are fluorescents. 2 Leds in an emergency exit sign if they are that proud of their solar PV why don't they have a big meter showing the total store consumption and what percentage of that is coming from the PV, both instantaneous and averaged over lets say a week. weird how thats seen as a good thing |
#19
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Mon, 23 Sep 2013 09:42:59 +0100, Roland Perry wrote:
Not the only example, they also say they are using LED lights in their (semi-underground) car park to save energy, but it's obvious they are fluorescents. Are you sure? There are LED strip lights that fit standard florry fittings, not sure it would be very easy to tell what the light source is behind a diffuser... -- Cheers Dave. |
#20
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Mon, 23 Sep 2013 03:30:25 -0700 (PDT), wrote:
if they are that proud of their solar PV why don't they have a big meter showing the total store consumption and what percentage of that is coming from the PV, both instantaneous and averaged over lets say a week. weird how thats seen as a good thing What is weird about giving the true facts? -- Cheers Dave. |
#21
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 23/09/13 08:29, Chris J Dixon wrote:
The Natural Philosopher wrote: Harry, the idiot who thnks inverters dont have any transformers. Whilst the former is a matter of debate, a lot of the latest inverters have no transformer, like this: http://www.sma-uk.com/en_UK/products/solar-inverters/sunny-boy/sunny-boy-3000tl-3600tl-4000tl-5000tl-with-reactive-power-control.html "...the new transformerless Sunny Boy is the ideal solution..." Chris just because the sales blurb says it is transformerless doesnt mean it is. -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
#22
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 23/09/13 12:03, Dave Liquorice wrote:
What is weird about giving the true facts? Dunno, but its a total rarity in any discussions about energy generation. After considerable thought I have decided that the most succinct thing to be asiad about what 'everybody knows' and what 'everybody syays' about electrical power generation is that it's *completely wrong*. -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
#23
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Mon, 23 Sep 2013 12:48:01 +0100, The Natural Philosopher
wrote: On 23/09/13 08:29, Chris J Dixon wrote: The Natural Philosopher wrote: Harry, the idiot who thnks inverters dont have any transformers. Whilst the former is a matter of debate, a lot of the latest inverters have no transformer, like this: http://www.sma-uk.com/en_UK/products/solar-inverters/sunny-boy/sunny-boy-3000tl-3600tl-4000tl-5000tl-with-reactive-power-control.html "...the new transformerless Sunny Boy is the ideal solution..." Chris just because the sales blurb says it is transformerless doesnt mean it is. But in this case they are transformerless. That can give rise to some interesting problems though. http://files.sma.de/dl/7418/PID-TI-UEN113410.pdf |
#24
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
In article , The Natural Philosopher
scribeth thus On 23/09/13 08:29, Chris J Dixon wrote: The Natural Philosopher wrote: Harry, the idiot who thnks inverters dont have any transformers. Whilst the former is a matter of debate, a lot of the latest inverters have no transformer, like this: http://www.sma-uk.com/en_UK/products...boy/sunny-boy- 3000tl-3600tl-4000tl-5000tl-with-reactive-power-control.html "...the new transformerless Sunny Boy is the ideal solution..." Chris just because the sales blurb says it is transformerless doesnt mean it is. How to they do the AC generation anyone know,? without any transformers or I presume inductive elements?. Is it all Capactive and how do they perform Galvanic isolation between the mains and the panels, surely theres no direct connection?.. -- Tony Sayer |
#25
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
tony sayer wrote:
How to they do the AC generation anyone know,? without any transformers or I presume inductive elements?. Is it all Capactive and how do they perform Galvanic isolation between the mains and the panels, surely theres no direct connection?.. Without a transformer, there is _no_ galvanic isolation. Have a look at page 22 (14 of the .pdf), onwards in this document. "Photovoltaics in Buildings Guide to the installation of PV systems 2nd Edition" http://www.bre.co.uk/filelibrary/pdf/rpts/Guide_to_the_installation_of_PV_systems_2nd_Editio n.pdf There is a decision chart which I am not going to reproduce, but the key details for average installs are "...it is the electrical separation of the mains from the d.c. using an isolating transformer that is the key determining factor when assessing the requirement for array frame earthing." "..freestanding ground mounted, or building roof mounted arrays (away from building metalwork) will normally not be within the equipotential zone." "Where the incoming supply is PME (the majority of domestic supply arrangements), the PME earth cannot be taken outside the equipotential zone. This is to prevent the potential shock hazard should the supply neutral ever be lost." "Install & bond to earth spike (Note: do not take PME out of equipotential Zone) (Note: Use 10 mm2 braid or equiv) " Chris -- Chris J Dixon Nottingham UK Plant amazing Acers. |
#26
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
In message o.uk, at
12:01:47 on Mon, 23 Sep 2013, Dave Liquorice remarked: Not the only example, they also say they are using LED lights in their (semi-underground) car park to save energy, but it's obvious they are fluorescents. Are you sure? There are LED strip lights that fit standard florry fittings, not sure it would be very easy to tell what the light source is behind a diffuser... Wouldn't they have numerous point sources visible (if only with a few percent difference in brightness), rather than one long source? -- Roland Perry |
#27
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 23/09/2013 15:16, tony sayer wrote:
Is it all Capactive and how do they perform Galvanic isolation between the mains and the panels, surely theres no direct connection?.. IIRC until recently the yanks banned non transformer inverters for grid tie applications because of the lack of isolation. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#28
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
In article ,
says... "Photovoltaics in Buildings Guide to the installation of PV systems 2nd Edition" http://www.bre.co.uk/filelibrary/pdf/rpts/Guide_to_the_installation_of_PV_systems_2nd_Editio n.pdf There is a decision chart which I am not going to reproduce, but the key details for average installs are That document is out of date now and the third edition is current, published on the MCS site in the installer standards section. http://www.microgenerationcertificat...ges/PV%20Book% 20ELECTRONIC.pdf It relaxes the requirement for earthing/bonding arrays a bit. |
#29
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On Mon, 23 Sep 2013 08:33:24 +0100, Vir Campestris
wrote: On 22/09/2013 18:07, harryagain wrote: Most of the energy stuffed back intot the sytem is used by nieghbours so in fact reducing the load on the system and making it more efficient. Locally perhaps, nationally unlikely. The big generators can't be easily throttled up and down, and lose efficiency when this has to be done. Because of where it is metered, that is beyond the location of bulk supply points, all UK domestic solar is viewed as reduced demand. Currently it is of such a low level that it is operationally lost in the noise. -- |
#30
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 23/09/13 20:56, The Other Mike wrote:
On Mon, 23 Sep 2013 08:33:24 +0100, Vir Campestris wrote: On 22/09/2013 18:07, harryagain wrote: Most of the energy stuffed back intot the sytem is used by nieghbours so in fact reducing the load on the system and making it more efficient. Locally perhaps, nationally unlikely. The big generators can't be easily throttled up and down, and lose efficiency when this has to be done. Because of where it is metered, that is beyond the location of bulk supply points, all UK domestic solar is viewed as reduced demand. Currently it is of such a low level that it is operationally lost in the noise. Exactly so. A cosmetic solution to a non-existent problem and if wind is anything to go by, one that's being pretty much abused by the FIT/ROC claimants. Its odd how wind that isn't centrally metered seems to operate at a much higher capacity factor than wind that IS centrally metered... -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
#31
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
BruceB wrote:
That document is out of date now and the third edition is current, published on the MCS site in the installer standards section. http://www.microgenerationcertification.org/images/PV%20Book%20ELECTRONIC.pdf It relaxes the requirement for earthing/bonding arrays a bit. Thanks for that, I haven't been keeping up. Interesting document. Chris -- Chris J Dixon Nottingham UK Plant amazing Acers. |
#32
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"The Natural Philosopher" wrote in message ... On 23/09/13 07:52, harryagain wrote: "Brian Gaff" wrote in message ... Of course a lot of these devices waste power when not a lot is being generated, and over time I'd suspect this adds up to quite a high amount. 5v is nothing, in any day the mains goes up and down far more than that amount. Brian The inverters in use these days are around 95% efficient. (No transformer) I think mine uses around 3w on standby. Harry, the idiot who thnks inverters dont have any transformers. Hey ****fer brains. All small parallel operation PV sytems have transformerless inverters these days. http://en.wikipedia.org/wiki/Grid-ti...ter#Technology |
#33
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"tony sayer" wrote in message ... In article , The Natural Philosopher scribeth thus On 23/09/13 08:29, Chris J Dixon wrote: The Natural Philosopher wrote: Harry, the idiot who thnks inverters dont have any transformers. Whilst the former is a matter of debate, a lot of the latest inverters have no transformer, like this: http://www.sma-uk.com/en_UK/products...boy/sunny-boy- 3000tl-3600tl-4000tl-5000tl-with-reactive-power-control.html "...the new transformerless Sunny Boy is the ideal solution..." Chris just because the sales blurb says it is transformerless doesnt mean it is. How to they do the AC generation anyone know,? without any transformers or I presume inductive elements?. Is it all Capactive and how do they perform Galvanic isolation between the mains and the panels, surely theres no direct connection?.. They have capacitor(s) which store energy as the AC volts cycle dips below the DC volts from the PV array. When working on them, you have to give the automatic discharge system time to work before fiddling about inside. |
#34
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"John Rumm" wrote in message o.uk... On 23/09/2013 15:16, tony sayer wrote: Is it all Capactive and how do they perform Galvanic isolation between the mains and the panels, surely theres no direct connection?.. IIRC until recently the yanks banned non transformer inverters for grid tie applications because of the lack of isolation. In days of yore the PV array ran at very low voltages (panels in parallel) & a tranformer was neccesary. In domestic arrays they are all in series these day,running at around 600-700 volts |
#35
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"Dave Liquorice" wrote in message ll.co.uk... On Sun, 22 Sep 2013 08:38:38 -0700 (PDT), jim wrote: One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc). The volts do change but not enough to notice. The voltage here drops by about 8 V when the E7 kicks in and 11 kW is instantly applied. A domestic PV array in bright sunlight produces less than 4 kW, only a bit above a rapid boil kettle... Arrays cab be as big as you like/can fit in/afford. The reason many are sub4Kw is that the smallest charge (money) band is 0-4Kw. The next is 4-10Kw, too big to fir on most domestic house roofs. |
#36
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"Dave Liquorice" wrote in message ll.co.uk... On Mon, 23 Sep 2013 07:45:01 +0100, Roland Perry wrote: A domestic PV array in bright sunlight produces less than 4 kW, only a bit above a rapid boil kettle... There's a big poster at my local Sainsbury's which says they generate enough electricity to boil every kettle in the town. But not simultaneously I suspect! Greenwash... if they are that proud of their solar PV why don't they have a big meter showing the total store consumption and what percentage of that is coming from the PV, both instantaneous and averaged over lets say a week. No reason at all why not. But the average Saintsbury shopper won't understand the numbers. |
#37
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"Roland Perry" wrote in message ... In message o.uk, at 09:07:34 on Mon, 23 Sep 2013, Dave Liquorice remarked: A domestic PV array in bright sunlight produces less than 4 kW, only a bit above a rapid boil kettle... There's a big poster at my local Sainsbury's which says they generate enough electricity to boil every kettle in the town. But not simultaneously I suspect! Greenwash... Not the only example, they also say they are using LED lights in their (semi-underground) car park to save energy, but it's obvious they are fluorescents. Why is it obvious? Some LED tubes fit into fluorescent light bodies. http://www.earlsmann.co.uk/sections/product/id/15 It could be just you is thick? |
#38
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
"The Natural Philosopher" wrote in message ... On 23/09/13 12:03, Dave Liquorice wrote: What is weird about giving the true facts? Dunno, but its a total rarity in any discussions about energy generation. After considerable thought I have decided that the most succinct thing to be asiad about what 'everybody knows' and what 'everybody syays' about electrical power generation is that it's *completely wrong*. Well you certainly know nothing about inverters. |
#39
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
harryagain wrote:
Arrays cab be as big as you like/can fit in/afford. The reason many are sub4Kw is that the smallest charge (money) band is 0-4Kw. I think you mean highest, in that above 4 kWp the FIT is lower. The next is 4-10Kw, too big to fir on most domestic house roofs. and requiring specific acceptance by your DNO. Chris -- Chris J Dixon Nottingham UK Plant amazing Acers. |
#40
Posted to uk.d-i-y
|
|||
|
|||
Stability of 240v supply under FIT tarrif?
On 24/09/13 09:07, harryagain wrote:
"The Natural Philosopher" wrote in message ... On 23/09/13 12:03, Dave Liquorice wrote: What is weird about giving the true facts? Dunno, but its a total rarity in any discussions about energy generation. After considerable thought I have decided that the most succinct thing to be asiad about what 'everybody knows' and what 'everybody syays' about electrical power generation is that it's *completely wrong*. Well you certainly know nothing about inverters. I've designed more of them than you have had solar panels fitted. -- Ineptocracy (in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
240v supply from 415V ? | UK diy | |||
415V immersion on 240V supply | UK diy | |||
Old Paper--The Stability Problem in Feedback Amplifiers Part 2 - The Stability Problem.part2.rar | Electronic Schematics | |||
Old Paper--The Stability Problem in Feedback Amplifiers Part 1 - The Stability Problem.part1.exe | Electronic Schematics | |||
Switch for oil boiler and pump 240V power supply | UK diy |