Grid intertied PV house service

[iwire]

The starting is not a problem, you have the Utility to take care of that. The PV just piddles along at a constant rate.

Except if the utility is down.

I thought it is commonly understood that the PV's are designed to shut down when the Utility is down. So it is NOT a problem.:roll:

Take a look at the one line, the inverter is in series with the load, not parallel to it.

If you read the whole thread you will see the customer wanted to run the heat pump from the batteries so the inverter is not the same as just a grid tied inverter.

See post 14.

 

[weressl]

Take a look at the one line, the inverter is in series with the load, not parallel to it.

If you read the whole thread you will see the customer wanted to run the heat pump from the batteries so the inverter is not the same as just a grid tied inverter.

See post 14.

It is incorrect to call it series, but it is immaterial to the point. The inverter and the Utility are parallel power sources. The contribution for an 'overload' - a motor startup - on the load side will come in inverse proportion to their source impedance. If the Utility source is not stiff enough, the PV inverter will try to increase the voltage to maintain it until it exceeds its own overload capability and will shut down.

As it has been said before the PV inverters are designed to source generate, eg. it needs to see a Voltage AND a frequency before they switch on and then the regulation will work on the voltage and frequency of the source parameters. If there is no Utility the PV is off. If you turn on a house generator, it better be sized properly to start the largest motor at the desired maximum other loads or the largest tungsten load under the maximum other loads.

Heat pump from batteries is a folly, it is not cost effective, but hey, we are talking about PV which is itself cost-ineffective, so throw money and resources away as much as you like.

Business' are embarking on eco-efficieny calculations and assign an arbitrary value to green gas generation value. It is a number out of thin air, based on hypothesis. Without it the greatest waste of resources is PV construction, hands down.

 

[iwire]

It is incorrect to call it series, but it is immaterial to the point. The inverter and the Utility are parallel power sources.

Yes, a standard grid tied inverter is parallel to the utility. I specify them when I engineer PV systems then I install them.

That is not the type of inverter George's drawing shows. The XW is a Hybrid type and is very likely in series with the load just as a UPS is.

General overview

http://www.xantrex.com/xw/00_install-backup.html

Installation instructions

http://www.xantrex.com/web/id/2169/docserve.aspx

 

[weressl]

Yes, a standard grid tied inverter is parallel to the utility. I specify them when I engineer PV systems then I install them.

That is not the type of inverter George's drawing shows. The XW is a Hybrid type and is very likely in series with the load just as a UPS is.

General overview

http://www.xantrex.com/xw/00_install-backup.html

Installation instructions

http://www.xantrex.com/web/id/2169/docserve.aspx

George's drawing alone does not define the power configuration.

The drawing is incorrect where it indicates bi-directional powerflow between the main panel and the Xantrex panel. That line is either the power input to the Xantrex panel or if it is the Xantrex PDP it will immediately destroy the Xantrex panel as described in the manual. It will also raise vigorous objection from the Utility as you are supplying power to them, but not complying with the power-down requirements.

To talk about a source and a load in terms of series and parallel is meaningless.

The overload capabilities of the system that you linked to are clear. That clearlyu answers Georges question if that is the inverter he is using, as long as he has the same information off of the heatpump.

 

[iwire]

George's drawing alone does not define the power configuration.

The drawing is incorrect where it indicates bi-directional powerflow between the main panel and the Xantrex panel. That line is either the power input to the Xantrex panel or if it is the Xantrex PDP it will immediately destroy the Xantrex panel as described in the manual. It will also raise vigorous objection from the Utility as you are supplying power to them, but not complying with the power-down requirements.

To talk about a source and a load in terms of series and parallel is meaningless.

The overload capabilities of the system that you linked to are clear. That clearlyu answers Georges question if that is the inverter he is using, as long as he has the same information off of the heatpump.

I think your mistaken, you think I am mistaken, it's just another day at Mike Holt's.

 

[weressl]

I think your mistaken, you think I am mistaken, it's just another day at Mike Holt's.

So tell me where I am mistaken and why?

Is George's drawing correct? Page 141 of the manual:
" CAUTION: Damage to Equipment
The inverter?s AC LOAD terminals must never be wired to any AC source such as a generator output or utility panel. This will cause severe damage to the inverter which is not covered under warranty."

Is this the type system that is not intended to sell power to the Utility or not?

Are the overload capabilities clearly indicated in the manual therefore enabling to make the comparative determination whether it is capable to serve a heat-pump or not?

Loads are connected in series or parallel with other loads but not power supplies. Power supplies are connected in series or parallel with other power supplies but not not loads. Loads are connected both series and parallel at the same time to the power supply and vice versa.

Actually the title of the OP is misleading: Grid intertied PV house service, as the XW system does not intertie with the grid,

 

[George Stolz]

The load is panel c. If I connected a generator to it, it might mess up the inverter, but that's not the configuration. Look closer.

 

[iwire]

So tell me where I am mistaken and why?

Is George's drawing correct? Page 141 of the manual:
" CAUTION: Damage to Equipment
The inverter’s AC LOAD terminals must never be wired to any AC source such as a generator output or utility panel. This will cause severe damage to the inverter which is not covered under warranty."

See George's post #47, you seem to be interpreting the drawing incorrectly. And yes I understand it may not be drawn using industry standard conventions but I deal with that all the time.

Is this the type system that is not intended to sell power to the Utility or not?

Yes.

Are the overload capabilities clearly indicated in the manual therefore enabling to make the comparative determination whether it is capable to serve a heat-pump or not?

Yes, and my advice to George was to check with the manufacturer.

So .... I am missing your point.

Loads are connected in series or parallel with other loads but not power supplies. Power supplies are connected in series or parallel with other power supplies but not not loads. Loads are connected both series and parallel at the same time to the power supply and vice versa.

Yada, Yada, Yada.

You have a couple of choices, learn to ignore me or learn to deal with my 'trade use' of terms.

We have a utility supply, we have a heat pump load, this inverter has an AC input and an AC output. It is installed between the supply and the load. I choose to call that in series and other electricians are going to understand what I mean. I understand that may not meet the standards you work under but I just really don't care.

Actually the title of the OP is misleading: Grid intertied PV house service, as the XW system does not intertie with the grid,

Strange you say that as the manufacturer feels it is grid tied.

Grid-Interactive Renewable Energy System with Backup Power

The XW System is the ideal solution for homes that are connected to the utility grid, where owners want to incorporate a renewable energy system with backup power. Most applications use solar arrays, but a wind generator, micro-hydro generator, and/or a fuel generator can also be incorporated into the system. Grid-interactivity allows excess energy that is generated to be exported to the grid, and allows the grid to act as an additional energy source to charge the system’s batteries. If the grid should fail, the inverter will automatically go into backup power mode, to supply energy from the batteries and energy inputs, to support the home’s electrical needs.

http://www.xantrex.com/xw/00_install-gridtie.html

 

[weressl]

The load is panel c. If I connected a generator to it, it might mess up the inverter, but that's not the configuration. Look closer.

I did look closer and you're right.

This crow tastes yummee, you want some?

 

[weressl]

See George's post #47, you seem to be interpreting the drawing incorrectly. And yes I understand it may not be drawn using industry standard conventions but I deal with that all the time.

Yes.

Yes, and my advice to George was to check with the manufacturer.

So .... I am missing your point.

Yada, Yada, Yada.

You have a couple of choices, learn to ignore me or learn to deal with my 'trade use' of terms.

We have a utility supply, we have a heat pump load, this inverter has an AC input and an AC output. It is installed between the supply and the load. I choose to call that in series and other electricians are going to understand what I mean. I understand that may not meet the standards you work under but I just really don't care.

Strange you say that as the manufacturer feels it is grid tied.

http://www.xantrex.com/xw/00_install-gridtie.html

Crow for breakfast and lunch?! Yumm.

But tell me; why do you think you are excempt from using the proper terms as they are defined in National Standard, just because it became a trade 'slang'? The issue is that it is 'like' a transformer and would you consider the transformer's primary and secondary side as connected in series with each other?

 

[iwire]

why do you think you are excempt from using the proper terms as they are defined in National Standard, just because it became a trade 'slang'?

Not just me, those around me as well.

Here on this forum I say things like 'grounded condutor' 'ungrouded conductor' etc. at work it would be hot and neutral. I choose to use the the terms that work for my intended audience. I really did not think anyone could misunderstand what I meant when I said

Take a look at the one line, the inverter is in series with the load, not parallel to it.

Did you really think I meant the inverter was wired in series like a line of resistors? I kind of doubt you did.

 

[weressl]

Not just me, those around me as well.

Here on this forum I say things like 'grounded condutor' 'ungrouded conductor' etc. at work it would be hot and neutral. I choose to use the the terms that work for my intended audience. I really did not think anyone could misunderstand what I meant when I said



Did you really think I meant the inverter was wired in series like a line of resistors? I kind of doubt you did.

Again, I asked you a question about the transformer to try to lead you to an answer, but you have not responded.

An inverter output can be wired series with another to increase the voltage, and parallel to increase the current. Same on the input side. The way how you use the term is meaningless and dangerous becuse it dillutes the technical meaning of the word and it becomes an ambiguous term.

I do not believe that you don't strive for better understanding of any subject, or that you yourself would not try to change ingrained things when you discover that they are wrong. (That would be un-American, wouldn't it? The whole foundation of this Nation rests uppon changing things that were wrong.)

 

[George Stolz]

I think Bob used just the right word, it jarred folks' thought processes a bit and got the facts straight before there were 20 posts confusing the issue.

 

[perry vogler]

grid tie solar drawling

grid tie solar drawling

George, the drawling on the grid tie system makes no since, looks as though your feeding the system twice like a loop. The size of the arays or the zantrex inverter are not shown but the drawling is defently incorrect. Even though the solar installer is not the EC making the final connection to the system, the EC contractor is responsable for the system. Have the dralings from the solar installer send the diagram to fsec to be certified. Guarantee it will be rejected. In a solar wiring diagram all details need to be included. Also see fsec requirments. Long way to go, good luck. Perry

 

[iwire]

George, the drawling on the grid tie system makes no since, looks as though your feeding the system twice like a loop.

Perry, you should really read the thread before jumping in.:grin:

He is not 'feeding the system twice', panel c is a load supplied by the inverter.

 

[George Stolz]

Man, was my original drawing that confusing?

I thought I simplified it quite a bit, compared to the Xantrex info I had when I started!

Here's the latest rendition, added some stuff. Also added color to the little arrows to aid in seeing where things are flowing. Green arrows are...you guessed it, green energy, and red is utility energy.

George, the drawling on the grid tie system makes no since, looks as though your feeding the system twice like a loop.

Not so, as Bob pointed out.

The size of the arays or the zantrex inverter are not shown but the drawling is defently incorrect.

And as I said in the first post, or immediately thereafter, I am not doing the PV portion of the install, therefore the specifics of the PV does not matter to me one iota, beyond how many watts the thing will spit out, so I don't overload it on my end.

Even though the solar installer is not the EC making the final connection to the system, the EC contractor is responsable for the system.

I am only responsible insofar as the level I load it to. I intend to have this firmly documented, as the owner has made it perfectly clear he intends to tinker once I am gone.

Have the dralings from the solar installer send the diagram to fsec to be certified.

I'll get right on that, PM me for my address, and you can mail me the check for my time.

Guarantee it will be rejected. In a solar wiring diagram all details need to be included.

And if this was a solar wiring diagram, not a service one-line, I would expend the extra effort to draw those details. That is on the solar installer (who answers to the AHJ) to provide for the AHJ (which does not answer to FSEC, and as far as I know has never stood on Floridian soil), which will not approve the installation without a detailed diagram and an inspection.

Long way to go, good luck. Perry

Thanks, and have a nice day.

 

[iwire]

Man, was my original drawing that confusing?

Not to me.

 

[George Stolz]

Here's some pictures of the install, for those interested...

The service:

Nothing like rerouting and adding communications conduits after the line voltage pipes are already done:

My version of Al:

Edit to add: There's those PV people, we don't talk to them...

 

[dereckbc]

Well put.:grin:

Having batteries with a grid tied system is just ridiculous. Trying to drive a heat pump from batteries ...... well sure if you have a free supply of batteries but otherwise no ..... :grin:

Battery back up grid tied system? That is a huge waste of money and certainly not green friendly. They do realize batteries have to be replaced about every 5 years don't they? That means the will never obtain an ROI and EROI.

Not to mention I have never seen an PV inverter that can handle large motor loads like a compressor. To do that will require an industrial grade inverter like the ones used on large scale UPS, and those are big BUCK$