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The issue of phase synchronization comes up only if you wish to send power to the grid. To supply your home relatively simple switching between the grid and the solar source can be done with no big issues. If however you wish to feed the grid it gets more complex.
I would tend to think that synchronizing any inverters being used for home power to the grid is sensible. I would think it would simply be implemented in any inverter system. Some detector picking up the grid and slaving an oscillator to it. A simple microprocessor system would do it for a few bucks.
Grid connected pv systems automatically follow the grid voltage phase. Stand alone systems do not. A system that is grid connected but provides backup power has to act as a stand alone system during system outages but have a way to safely reconnect when power is restored. That is more complex than an $80 switch and people advocating such a solution clearly do not understand the complexity of the issue. That will lead to a dangerous situation. This is why most electric utilities will not allow a DIY system to interconnect.
Grid connected pv systems automatically follow the grid voltage phase. Stand alone systems do not. A system that is grid connected but provides backup power has to act as a stand alone system during system outages but have a way to safely reconnect when power is restored. That is more complex than an $80 switch and people advocating such a solution clearly do not understand the complexity of the issue. That will lead to a dangerous situation. This is why most electric utilities will not allow a DIY system to interconnect.
I would think it would be perfectly OK for a standalone system to synch to the local grid if a suitable signal is available. Just an additional cord set to an outlet on the grid system and $10 of electronics.
And of course any such system has to have a way to safely connect to the grid. Do you believe that such systems are assembled grid connected? So every system that is to be grid connected has to be able to disconnect and reconnect.
I would think it would be perfectly OK for a standalone system to synch to the local grid if a suitable signal is available. Just an additional cord set to an outlet on the grid system and $10 of electronics.
And of course any such system has to have a way to safely connect to the grid. Do you believe that such systems are assembled grid connected? So every system that is to be grid connected has to be able to disconnect and reconnect.
The grid connected systems get their voltage signal from the grid. It is set up to stay in phase. There may be systems that will work both ways as I described. It isn't rocket science, but there has to be a demand for it and the electronics will cost well more than $10.00. I can't see much demand. For most people outages are few and short.
The grid connected systems get their voltage signal from the grid. It is set up to stay in phase. There may be systems that will work both ways as I described. It isn't rocket science, but there has to be a demand for it and the electronics will cost well more than $10.00. I can't see much demand. For most people outages are few and short.
Not in rural areas where there is little redundancy and if you live in a cold climate, lines can ice up and break. I live in Hawaii now and here we have constant outages from high winds.
I talked to Enphase and asked if they had thought about addressing the problem of a grid-tied system being able to power just the house if the grid goes down and they said they were working on a new product for that. But I haven't seen it. In any event somebody will come up with something one day. But it will be more complicated than just a switch and any DIY thing is probably not going to fly with the local power company.
It can be done for about $80. Not exactly a huge percentage of a 20k grid-tie system.
You're not going to fix this issue with $80 especially if you want to fuly utilize all the power being generated. The power being generated by the panels fluctuates and so does your demand. You need to be able to store that power to provide a buffer. You could use a small amount of battery storage but that limits how much power you can store and what you can run.
You're not going to fix this issue with $80 especially if you want to fuly utilize all the power being generated. The power being generated by the panels fluctuates and so does your demand. You need to be able to store that power to provide a buffer. You could use a small amount of battery storage but that limits how much power you can store and what you can run.
Agreed- the transfer switch solves the issue of getting raw power (400v - 600v DC) from your panels (assuming string inverter, which is very popular these days), but you'll have to deal with the voltage issue and also the fluctuation issue. In any given day my system generates between 0 and 12,000 watts, and one big fluffy cloud can take it from 12,000 watts to 5,000 watts for a few minutes. So you wouldn't want to be drawing any more than 3,000 - 4,000 watts at any given time that the sun is up, unless you have a battery bank to buffer the power.
If you have micro-inverters, then your transfer switch won't work unless you can find a way to fool the inverters into thinking you have grid power. Then you still have the issue with variability.
In many cases, the cheapest solution is a traditional gas/propane generator setup. The only other "easy" solution is to use a grid-tied inverter that has an outlet that stays hot when the grid is down, but that's basically the equivalent of having a small 2,000 watt generator since those outlets are very limited in the power they produce.
Taking 4000 watts from a 12000 watt system producing full power will degrade the pc cells.
So if something (load, battery) is not accepting the full output of a solar panel, that actually damages the solar panel itself? If so, I didn't know that.
So if something (load, battery) is not accepting the full output of a solar panel, that actually damages the solar panel itself? If so, I didn't know that.
Yes
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