Any one tried running a large capacitor with a grid tie?

oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
I put up my wind turbine and power out put was very choppy.
When I would see the little turbine spinning more than fast enough to put out power and the kill-a-watt meter would be reading 0.
It takes that inverter what seems like up to 10 or 15 seconds to do what ever it needs to do to start putting out power out to the grid.
So I added a 0.1F 40v capacitor and that seemed to help some.
The next day I found my 2.4F 28v capacitor and it made a big difference on the more windy days. But it seems to hurt the wind turbine out put on the less windy days. When the capacitor is discharged it almost acts like the + and - are shorted together when the blades try to first turn. But as long as its an active day and the blades almost never stop it seems to help whole lot.

Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 30,494 admin
    Re: Any one tried running a large capacitor with a grid tie?

    Interesting, what brand/model of GT inverter are you using with your wind turbine?

    And, by the way, you are correct about how a large capacitor looks to your wind turbine when at zero volts--Pretty much like a dead short that will accept lots of current as the capacitor recharges. It may very well stall the wind turbine until the capacitor has done some charging first.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    Its some cheap chinese inverter off ebay. I cant remember the name because I took a 3 inch hole saw to the top of it to install a larger fan to so it could run at more than 200 watts for more than a few minutes with out over heating.
    That big fan is disconnected because the inverter rarely puts out more than 80 watts so the fan isn't needed, yet.
    I ordered a 12 blade hub and six, 70 inch diameter blades and should get here any day now.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    :confused: This is an approved grid-tie install, is it?
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    This setup is approved by me.
    Since I have worked on real power generation for the last 9 years I learned a few things and picked up a few toys over the years.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Any one tried running a large capacitor with a grid tie?
    oil pan 4 wrote: »
    This setup is approved by me.
    Since I have worked on real power generation for the last 9 years I learned a few things and picked up a few toys over the years.

    It is necessary to legal nit-pick here, lest someone casually perusing the forum gets the wrong idea:

    Does the utility it is connected to approve of it?
    Does the local building inspector say it meets code?

    Knowing what you're doing and doing it legally are not always the same thing. Sorry to mensch. :blush:
  • GreenerPowerGreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?
    oil pan 4 wrote: »
    Its some cheap chinese inverter off ebay.
    There is a reason why those inverters don't have UL1741 stamps.

    GP
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    After testing and modifying the inverter I had to realize failure as a possible option.
    So I put it out side in a "vented" ammo can under some shade and fused the high voltage to 5amps, also added a thermal fuse. So it can try to short out and catch on fire and if it does it wont hurt anything but its self.
    The low voltage wiring exceeds code, its built to handle more than what the wind turbine is rated for but it has yet to produce more than 100 watts. The high voltage side goes to a standard outlet and into existing house wiring.
    Just keeping it simple.
    The local tiny small town co op utility doesnt have anything on grid tie systems.
    I am not going to try to push any surplus power on the grid, I have a feeling the simple digital KwH meter on my house cant tell if the power is coming or going.
    Its still in the test phase.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • HuckMeatHuckMeat Registered Users Posts: 24
    Re: Any one tried running a large capacitor with a grid tie?
    oil pan 4 wrote: »
    After testing and modifying the inverter I had to realize failure as a possible option.
    So I put it out side in a "vented" ammo can under some shade and fused the high voltage to 5amps, also added a thermal fuse. So it can try to short out and catch on fire and if it does it wont hurt anything but its self.
    The low voltage wiring exceeds code, its built to handle more than what the wind turbine is rated for but it has yet to produce more than 100 watts. The high voltage side goes to a standard outlet and into existing house wiring.
    Just keeping it simple.
    The local tiny small town co op utility doesnt have anything on grid tie systems.
    I am not going to try to push any surplus power on the grid, I have a feeling the simple digital KwH meter on my house cant tell if the power is coming or going.
    Its still in the test phase.

    That kwh meter on the side of your house can't tell if power is coming or going, so it will always count up, even if you are "selling" energy back to the grid. So now you get to pay for sending power back (at the same rate you buy normal power for), in addition to the liability of burning your house down or killing someone.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    This inverter cant island. It doesn't have the circuity and I tested it. It produces 0 most of the time any way.
    The only way the wind turbine is going to kill some one is if they climb a ladder and stick their head in the blades on a windy day. If they do that then they had it coming.
    How can the inverter burn down the house if its out side and about 50 feet away from the house and in a metal box? I would really like to hear how that works.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • chevensteinchevenstein Solar Expert Posts: 100 ✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    It can be tempting to play with stuff like this in your existing infrastructure, but the stakes are just too high if you're grid tied. If you were a lineman working where someone had some cheap, unlisted equipment hooked up that they claim will not island would you trust your life to their judgment and their equipment? Maybe it doesn't island now, but what if it fails later on in some way that causes that to change? Again, as the lineman, would you trust your life to this?

    I love experimenting and pushing boundaries but only when it is at my exclusive risk. I also hate being told what I can and cannot do, but please think about the risk to others and put yourself in the shoes of someone whose life or well being relies on the actions of someone else, especially when they're conducting an experiment with questionable equipment.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    The problem is it cant island. This inverter would have to spontaneously grow a timing control circuit. I would have to call it as an analog boosted feed back isolator. It has to have an external frequency source to feed power back on to.
    Islanding is more a problem for real power generation sources, like large diesel power backups.

    Well a thunder storm conjured its self out of no where friday and I pulled down the wind turbine.
    The problem is the power goes out easy and I didn't want my bare unfinished metal wind turbine getting rained on or have the power go out and free wheel in the wind until it spins its self apart.
    So my new safety device will be a manual activated, auto disconnect hold in relay.
    The way it works is I plug in and no power goes to the inverter until I close the momentary toggle. That closes the normally open contacts with a hold in circuit. When power is cut the relay will go to its normally closed position where I will have my 1Ohm 100w resistor wired in. It will stay normally closed until power is turned back on and some one flicks the switch.
    If it fails it will fail to the normally closed position.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • BB.BB. Super Moderators, Administrators Posts: 30,494 admin
    Re: Any one tried running a large capacitor with a grid tie?

    If you have a double throw relay on the DC side--You should just be able to short the output the windings of your wind turbine and stall the blades (if shorted output is valid for your turbine).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    The owners manual said never to short the turbine for braking. Plus its never a good idea to short a real generator or alternator unless for some reason you want to burn it up.
    If I short it, that could melt the contacts in the relay together if the winds are going strong enough when the power goes out. That is the fail safe mode, if it fails it will fail in grid dissconnect mode.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • GreenerPowerGreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?
    oil pan 4 wrote: »
    The problem is it cant island. This inverter would have to spontaneously grow a timing control circuit. I would have to call it as an analog boosted feed back isolator. It has to have an external frequency source to feed power back on to.
    Islanding is more a problem for real power generation sources, like large diesel power backups.

    Well a thunder storm conjured its self out of no where friday and I pulled down the wind turbine.
    The problem is the power goes out easy and I didn't want my bare unfinished metal wind turbine getting rained on or have the power go out and free wheel in the wind until it spins its self apart.
    So my new safety device will be a manual activated, auto disconnect hold in relay.
    The way it works is I plug in and no power goes to the inverter until I close the momentary toggle. That closes the normally open contacts with a hold in circuit. When power is cut the relay will go to its normally closed position where I will have my 1Ohm 100w resistor wired in. It will stay normally closed until power is turned back on and some one flicks the switch.
    If it fails it will fail to the normally closed position.

    You think this is fail-safe ? These inverters are transformer-less designs, an internal failure could connect its internal ~200V "mod-sine" to the line and hold your "auto-disconnect" connected. In a power outage, this kind of failure could potentially send KVs up the utility transformer (reverse as step-up transformer). This ~200V mod-sine (i.e. ~300V peak) could destroy the electronics connected to the line. Not to mention pushing a ~200V mod-sine to the line is no where accepted PF for grid-tie. Some of the smart meters can report poor PF generation, the utility can disconnect your service when they collect enough evidence.

    GP
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    My generation PF is 1.
    So thats BS. I already tested it. I check the power factor almost ever time I see it generating power, PF is always 1 no more, no less.
    I can put an over voltage dissconnect on there no problem, I think I have one laying around. It kicks in at 132 volts +/- 2 volts and is manually reset.
    I have been doing this power generation thing for long time, the wind turbine and power inverter are new but the faults and dangers are the same.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • MisterBMisterB Solar Expert Posts: 156 ✭✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?

    I'm not going to comment on the grid tie part of your setup but as far as the wind turbine, you can usually safely short the output to brake it if it is not spinning or spinning at a low rpm. You should have a dump load on your controller and, if you can manually engage it, it will slow your turbine down and serve as a brake. There are mechanical safety issues with any turbine. The main one is blades breaking and pieces flying off. If the turbine spins without a load, this is known as freewheeling and is a dangerous condition at high wind speeds which is when blade failure is most likely to occur. Putting another 20 inches of rotor diameter on your turbine is going to extract more power from the wind but it is also going to make it spin faster and stress it mechanically much more at high wind speeds which is going to make braking and furling to control the turbine under high winds much more important.
  • BB.BB. Super Moderators, Administrators Posts: 30,494 admin
    Re: Any one tried running a large capacitor with a grid tie?

    Remembering that I have made a living designing equipment that connected to the utility (and battery banks) and have gotten UL, TUV, CSA, Bellcore/Telcorida for my systems... What follows is my personal opinion.

    I don't think that OP4's single small GT inverter is a significant hazard to the the "grid". The amount of available energy from the small GT inverter (MSW or TSW) is so small as too be "round off" error... Whether it was operating correctly or not. The amount of junk that "normal" equipment imposes on the grid (non linear current wave forms, motors driving loads with large momentum, welders, florescent and other arc based lamps, frequency converters, etc...) that impose huge non-sine and phase lagging current on the utility lines, legally, such a single small unit is not going to be a safety issue.

    Heck, it is real easy to make a home made GT power system... Just take an electric induction motor and drive it with a fuel driven engine... Set the engine to drive the induction motor faster than line frequency (1,800 rpm for a 4 pole motor) and the motor will output current to the grid and run the meter backwards. We used to do this with an electric motor/generator sets in Electric Shop courses.

    That is not to say that if there where a lot of these guerrilla non-Listed GT inverts on a single utility transformer (one one with multi-kW array, or several homes with smaller arrays) would not cause an issue with pole transformer (typically overheating)... (the utilities had a little red light on, at least some of their, transformers when they where at maximum load--I understand they have painted over the bulbs/ignore the red lights on the poles in our area).

    Also, it would not be hard to believe that a utility or state PUC (or even the Feds) would use the fact that these non-Listed GT inverters are being connected to solar panels and utility/regulated power lines would not be used as a basis to implement harsh new rules/penalties on guerrilla GT solar PV/power systems (huge fines, more inspections/paper work/fees--or even making a violation a felony under the Patriot Act as an attack on the infrastructure).

    But enough tinfoil hat time...

    The real issue, from my humble point of view, is the simple issue of a non-Listed device (GT inverter) that connects to low voltage DC devices (solar panels+wiring).

    Much of what my design review and verification (including FCC, UL, NRTL, etc.) testing revolved around was validating that the design met industry/NRTL practices and that any single and subsequent fault would fail in a "safe" manner (the NRTL folks do not like using the world "Safe" as somebody could sue over somebody burning their house down when a pet rabbit chewed through the coffee maker power cord there for the design was not safe).

    My concern would be that the GT inverter or the DC wiring/solar panels could catch fire and light off nearby materials/shock somebody working on the unit if something "goes wrong".

    OP4 says he has taken care of those last issues--And I am willing to believe him. There is nothing more to do here.

    Would I play with a non-listed GT inverter system and plug it into my home's wiring to see how it works--Sure... Would I mount the system in my home and put the panels on my roof for unattended/long term operation (with or without building permits/utility approval)... No.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GreenerPowerGreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Any one tried running a large capacitor with a grid tie?
    BB. wrote: »
    ...I don't think that OP4's single small GT inverter is a significant hazard to the the "grid".
    -Bill
    True if the grid is up. When the grid is down, a ~200V 300W mod-sine going up the utility transformer is plenty dangerous for utility workers.
    I don't know the specifics of the OP4's inverters. So if he says its PF is 1, just take his words for it. I was paid to look at various of those Chinese eBay "grid-tie" inverters to understand how those work to improve the smart meter's codes :cool:
    GP
  • BB.BB. Super Moderators, Administrators Posts: 30,494 admin
    Re: Any one tried running a large capacitor with a grid tie?

    GP,

    I figured somebody would interested in finding these guys. ;)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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