Solar Companies Seek Ways to Build an Oasis of Electricity (panels a FAIL after Sandy)

"It's the same reason that before home generators kick on, they disconnect from the grid. With solar panels it is a little different because to run a home with solar panels big batteries are needed to get you through the night. So when the grid goes down the solar panels disconnect themselves and you have great big reflecting panels on your roof."

Are these people too stupid to go out to their power panel and OPEN THE SWITCH that connects their home to the grid??? At which point the solar system is INDEPENDENT and "should" be capable of providing power to the home (at least partially).

If this capability isn't available (I can't see how it would not be), then the installers of said systems are due for a LOT of lawsuits.

Unfortunately it's not just a switch as most grid tie inverters have a protective circuit that is integral with the system. It can't be bypassed as the parameters are burned into the eprom or at very least set by software that the end user has no access to. Likewise, no "switches" it's all solid state. The inverter will look for a narrow band of voltage coming in from the grid which by itself would be easy to overcome. The hard part is frequency. The system also looks for a perfect sine wave of 60 cycles per second, give or take maybe .05 hertz. If an outside power source is making 59.94 hertz or 60.06 hertz it locks down the system. Not many generators are that precise. Also there is the problem of what happens when say 42 panels start feeding back into a 600 watt "pilot" generator at, say 10,000 watts. I don't pretend to know the answer to the last one.

If there are any electrical gurus out there that know how to get past those hurdles, especially the frequency one, please feel free to jump right in.

"Unfortunately it's not just a switch as most grid tie inverters have a protective circuit that is integral with the system. It can't be bypassed as the parameters are burned into the eprom or at very least set by software that the end user has no access to. Likewise, no "switches" it's all solid state. The inverter will look for a narrow band of voltage coming in from the grid which by itself would be easy to overcome. The hard part is frequency. The system also looks for a perfect sine wave of 60 cycles per second, give or take maybe .05 hertz. If an outside power source is making 59.94 hertz or 60.06 hertz it locks down the system. Not many generators are that precise. Also there is the problem of what happens when say 42 panels start feeding back into a 600 watt "pilot" generator at, say 10,000 watts. I don't pretend to know the answer to the last one.

I'm not talking about a switch on the inverter, I'm talking about the main power entry panel to the home. There HAS to be a way to isolate the house from the utility line to allow people to work on the house power circuits. Any electrician who would work on such a system without a MECHANICAL isolation switch WITH A POSITIVE LOCKOUT is an idiot. I know "I" damned well wouldn't trust an "electronically controlled" switch as sufficient protection.

And anybody who is so stupid as to buy a solar power system that DIES when the grid goes down deserves whatever consequences happen to them as a result.

Okay Wonder Warthog, let me explain this more clearly.

There are MECHANICAL ISOLATION SWITCHES between the house and grid and also between the house and the solar panels. You may flip those switches and isolate or de-isolate anything and everything until your heart is content but it is not going to make the inverter work. The whole idea of the system working that way is to keep idiots who don't have a clue from flipping those switches without knowing what they are doing and endangering the line workers who might get a taste of that ten thousand kilowatts or so feeding back into the main lines. They would be endangering themselves, lineworkers and even their neighbors. A photovoltaic system can be easily designed to function off grid as well but that involves maintaining batteries, lots of extra expense, more wires and more. It is a different kind of system, with a different objective.

I suppose you could just as easily say that those who don't buy generators and keep plenty of fuel for when the grid goes down deserve whatever consequences happen to them as a result. I won't say it but you can.

"There are MECHANICAL ISOLATION SWITCHES between the house and grid and also between the house and the solar panels. You may flip those switches and isolate or de-isolate anything and everything until your heart is content but it is not going to make the inverter work. The whole idea of the system working that way is to keep idiots who don't have a clue from flipping those switches without knowing what they are doing and endangering the line workers who might get a taste of that ten thousand kilowatts or so feeding back into the main lines. They would be endangering themselves, lineworkers and even their neighbors.

Sorry, but simply stupid. It is quite easy to build in the intelligence on both sides of the mechanical switch to the grid to disallow the passage of current in either direction unless the correct handshaking is in place. This is essentially what a ground-fault-interrupt circuit does, but in two directions instead of one. The appropriate "triggering signal" is the presence of a 60Hz "signal" simultaneously on either side of the mechanical switch. But IMO, virtually any owner can be trained to properly handle this situation.

"A photovoltaic system can be easily designed to function off grid as well but that involves maintaining batteries, lots of extra expense, more wires and more. It is a different kind of system, with a different objective.

I understand the differences in the systems quite well, thank you. And my point is that engineers who design and companies who sell such systems without pointing out that the solar-power system does not offer off-grid/backup capability without fully informing those who buy them are totally unethical. And yes, anyone who buys such a system IS an idiot for not doing the necessary homework to understand is capabilities (or lack of capabilities).

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