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Power firm pushes solar electrification of homes


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Are you suggesting,  connecting your solar power system to the grid without informing the power company ?

 

I hope not

 

Of course not. I didn't say anything one way or another about informing the power company. That point had never come up. However, whether the power company will pay you for excess generation or not has no relevance on informing the company. The only thing I suggested was that not having a buy back agreement is not necessarily a barrier to adding solar generation...provided you don't add more generation than you will use in any given month (look at lowest monthly usage).

 

Also, anybody who installs solar generation to a home that is hooked to a utility grid ABSOLUTELY MUST install an automatic cutoff...to ensure that if power goes off on the grid, the solar generation will be isolated (to prevent back feed that could be lethal to linemen in the event of an outage if they assume the line is dead). Obviously, you install the automatic cutoff so it disconnects from the utility grid...and remains connected to the house load.

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As already stated many times, they will install 2 digital meters  one will count in and the other will count out   My meter here is digital   btw it is easy to stop a mechanical meter if the mecha

To reiterate, I know very little about grid-tied systems. You may know more than I do. I can only state what I do know.   Either way, I know a house would not be connected to the DC side of the inve

This should help alleviate some of the power problems.    

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rainymike

Grid tied solar actually "reduces" the line transmission losses because your excess power is more likely to be used locally. I'd put up a couple of KW's of panels immediately if a program existed in my area.

You're probably right about that. Somehow I don't think that's what they have in mind though. 

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Also, anybody who installs solar generation to a home that is hooked to a utility grid ABSOLUTELY MUST install an automatic cutoff...to ensure that if power goes off on the grid, the solar generation will be isolated (to prevent back feed that could be lethal to linemen in the event of an outage if they assume the line is dead). Obviously, you install the automatic cutoff so it disconnects from the utility grid...and remains connected to the house load.

 

Not exactly. The grid tied inverter will disconnect.

 

I know very little about grid tied systems. But, that is one thing that must happen, to keep your system from sending power into the mains.

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Not exactly. The grid tied inverter will disconnect.

 

I know very little about grid tied systems. But, that is one thing that must happen, to keep your system from sending power into the mains.

 

IF you have your house connected to the DC side of the inverter, then an automatic cutoff that is integral to the inverter is great. However, if you are running AC in your house, and have the inverter between the solar generation and the house load, then having your inverter shut off will kill the power feed to the house as well as the power feed to the grid.

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Who says the inverter will shut down "the grid cut off" could be build into the grid inverter

 

anyway the grid inverter will have to have some electronics that will keep the inverter in phase

with the grid  if not easy to build the grid cut off into the grid inverter also

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IF you have your house connected to the DC side of the inverter, then an automatic cutoff that is integral to the inverter is great. However, if you are running AC in your house, and have the inverter between the solar generation and the house load, then having your inverter shut off will kill the power feed to the house as well as the power feed to the grid.

 

To reiterate, I know very little about grid-tied systems. You may know more than I do. I can only state what I do know.

 

Either way, I know a house would not be connected to the DC side of the inverter, ever. The solar array is connected to the DC side of the inverter, not circuits in the house. The inverter then connects to the AC side going to the mains. These can be simple inverters that plug directly into a receptacle in your home. The energy produced simply is sent back into the mains via the power point it is connected to. When the mains go down, the inverter detects this and disconnects the output. 

 

Larger systems, I believe, would be connected directly to a power distribution panel.

 

The only way one would have DC circuits in the home, is if they are running a hybrid system composed of batteries, and possibly - other forms of input, like wind and / or hydro. However, the vast majority of grid-tied systems, from what I have learned, are set up more for net metering than to provide power if the mains are down.

 

But, even if you are talking hybrid systems, the inverter would still be the "automatic switch". It would switch from the mains to the batteries, as necessary. There are no other "automatic switches" that I know of (that would perform this function), even in a hybrid system. 

 

Grid-Tied System (Grid-Tied Only)

grid-tied-solar-system.png

 

Hybrid System (Grid-Tied / Off-Grid)

hybrid-solar-system.png

 

Off-Grid System (Off-Grid Only)

off-grid-solar-system.png

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      In Sun Valley Idaho they used a very trick meter that not only could run backwards, it would isolate, or prevent back feed, to a dead feeder. It also communicated its status back to the utility company, and prevented back feed in case of phasing issues ( problems with the inverter). The utility workers need assurance that all power to a line is secured prior to working on it, and that under no circumstances it gets powered up from any source while they are working on it. This is why the laws are so strict about generator transfer switches. To have a hundred of these on a line, they must be done right. If just 1 fails, the others since the power, and they all come on, here you go. So the company MUST be aware of these generators (solar or otherwise) that back feed there grid.

     I saw a video about it a few years back on cable TV. Worker protection is a major concern in cases where feeders are getting powered from multiple sources.    

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Worker protection is a major concern in cases where feeders are getting powered from multiple sources.

 

Can you guess how many cheap, Chinese made grid-tied inverters are attached to the power grid in the US nowadays? I can only imagine.

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to_dave007

Can you guess how many cheap, Chinese made grid-tied inverters are attached to the power grid in the US nowadays? I can only imagine.

Friend of mine here in Canada works part time for company which imports a line of electronics (battery chargers - from very small to very large). These chargers are designed and certified in Canada (CSA and UL for USA usage) and manufactured in China, and imported and sold through large chain stores. My friend is electronics wiz and his role is to dis-assemble a random sample of the units that were sold and returned as non functional, to assess what the problem was, and make the required design change. The biggest cause of problems is a seemingly random willingness to substitute parts (i.e. resisters and capacitors) without authorization.

 

This wouldn't likely happen with Apple or other RFH (Really F**King Huge) volume manufacturers.. but the small and mid sized guys, or any venture without a western style QA function is likely to have this issue. They complained to one manufacturer.. and the manufacturer told them that their volume wasn't high enough and dropped them.

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Friend of mine here in Canada works part time for company which imports a line of electronics (battery chargers - from very small to very large). These chargers are designed and certified in Canada (CSA and UL for USA usage) and manufactured in China, and imported and sold through large chain stores. My friend is electronics wiz and his role is to dis-assemble a random sample of the units that were sold and returned as non functional, to assess what the problem was, and make the required design change. The biggest cause of problems is a seemingly random willingness to substitute parts (i.e. resisters and capacitors) without authorization.

 

This wouldn't likely happen with Apple or other RFH (Really F**King Huge) volume manufacturers.. but the small and mid sized guys, or any venture without a western style QA function is likely to have this issue. They complained to one manufacturer.. and the manufacturer told them that their volume wasn't high enough and dropped them.

 

Last year, I purchased through eBay, two Chinese made PWM controllers. My intention was to use them long enough to be able to compare their reliability against two other known quality controllers. They didn't last long enough for me to do a proper test. One even ruined the battery I had it connected to, before I had a chance to disconnect it. Of course, I got both, shipped to me, for something under $25 USD? The cheapest, reliable and quality made controller you will find in the US, will run a bit over $80 USD.

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Can you guess how many cheap, Chinese made grid-tied inverters are attached to the power grid in the US nowadays? I can only imagine.

 

For sure. But the video I saw on cable a few years back did mention this concern. The inverter must match fazing to the grid, and shut off if the grid was off. Then they were using a separate "trick" meter that offered redundancy by sensing any failure of the inverter. In the apartment complex, in Casa Grande Arizona where my daughter lives they have solar panels on the roofs of all the car ports and south/west facing roofs. The electricity enters the grid separate from her apartments meter, so her meter does not run backwards, but the building owners got meters that do. They must have at least double redundancy safeties to secure all this for workers safety. There might be a hundred inverters in just one big apartment complex in that area.

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The inverter must match fazing to the grid, and shut off if the grid was off.

 

That's what I am wondering - if the Chinese made units will ever fail doing that. They aren't known for their quality workmanship in electronic devices.

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That's what I am wondering - if the Chinese made units will ever fail doing that. They aren't known for their quality workmanship in electronic devices.

 

There's the problem: the Chinese units are fazing when they should be phasing.

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There's the problem: the Chinese units are fazing when they should be phasing.

 

LOL. Sorry, I am a blonde.

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to_dave007

There's the problem: the Chinese units are fazing when they should be phasing.

Doesn't phase me.. We'll faze in the new ones over the next year.

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