Another P&P Vendor - Can plug and play work in the US?

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  • igor1960igor1960 Solar Expert Posts: 85 ✭✭✭✭
    vtmaps wrote: »
    Well then, you still have a problem: Start inverter. Add loads to circuit, start another inverter, add more loads, start another inverter, add more loads, call fire department.

    --vtMaps

    OK, just thinking load:
    Pseudocode:
    {
    Production = 0; // sum of all Inverter currents
    Load = 0; // sum of all load currents
    CB = 15; // we have 15AMP circuit breaker;
    DO 1, N
    {
    // -- Start N inverter: overall circuits Production current:
    Production=Production+ProductionN;
    // -- Add LoadN to circuit: overall circuits Load current:
    Load=Load + LoadN:
    // -- Net:
    Net=Production-Load;
    // check
    if(Net < 0) { Production=0; (all inverters stop); Net = Load; }
    if(ABS(Net) > CB) { CB Trip; circuit stops; break }
    }
    FOREVER(Time)
    {
    Net=Production(Time)-Load(Time);
    if(Net < 0) { Production=0; (all inverters stop); Net = Load; }
    if(ABS(Net) > CB) { CB Trip; circuit stops; break }
    }
    }

    So, our circuit stops completely on possible conditions (CB trip):
    1. ABS(Net) > CB current;
    3. Net < 0: the circuit becomes LOAD, ALL inverters will stop; at that moment Production becomes 0 and then if Load > CB current => CB trip

    Most important:
    4. Max. current at any possible point inside the circuit is not more then Net (??? Check remark below) ;
    5. As we were adding sequentially Production1/Load1/Production2/Load3...ProductionN/LoadN - none of each at the moment of addition is more then rated CB current.

    Remark:
    Agree, however that installed at 0/min level currents (at night for example, when both ProductionN and LoadN are at 0), and if then extremely synchronized max. Circuit current is unpredictable...
    That's something to think about -- maybe it's unresolvable...
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    igor1960 wrote: »
    So, our circuit stops production at first Load>Production and either sum Production > CB current or Load > CB current.

    It is possible to have a combination of production and loads that will not shut down the inverters and will not trip the CB, and will still result in exceeding the ampacity of your "dedicated" circuit wiring: Turn on a 14 amp inverter, turn on a 13 amp load, turn on a 13 amp inverter, turn on a 13 amp load, turn on a 13 amp inverter, turn on a 13 amp load, call the fire department.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • solar_davesolar_dave Solar Expert Posts: 2,366 ✭✭✭✭
    Not to go full circle, but if it is a dedicated line whey not just hard wire the dedicated line. Much more acceptable to the code people. Remove the plugs and you remove much of the problematic conditions.
  • igor1960igor1960 Solar Expert Posts: 85 ✭✭✭✭
    solar_dave wrote: »
    Not to go full circle, but if it is a dedicated line whey not just hard wire the dedicated line. Much more acceptable to the code people. Remove the plugs and you remove much of the problematic conditions.

    Yep, looks like this this is the only feasible approach. But then, "P&P" part becomes utopia. I'm about to give up on possible implementation on the site of P&P inverter.

    The only possible, solution that I could see: with P&P inverter having production: is checking Voltage in L1 compare with Voltage in Neutral -- if P&P inverters and/or other producing devices are on the circuit and no LOAD is installed -- then Votage in Neutral would be opposite in phase to voltage in L1 (180degrees rotated, when L1 is positive - N is negative and when L1 is negative N is positive). Voltage in N- couldn't be 0 or in phase with L1, as we have production only on the circuit, and therefore 0 or above at neutral will indicate then there is a LOAD in the circuit equal to or above Production. But even if this is implemented: still no warranty that some of the receptacles with LOAD has positive voltage in neutral and that might cause unpredicatble circular current between LOAD and Production without CB involved. So, the only way, is to move protection in such circuits into all receptacles (special receptacles that dissalow LOAD, by allowing current only from Neutral to L1), but then again "P&P" part becomes utopia.
  • solar_davesolar_dave Solar Expert Posts: 2,366 ✭✭✭✭
    And Hardwired UL approved inverters do exist today! ;)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Well some of us are not surprised at the results.

    Just imagine how much time would have been saved if only people would listen to begin with.
  • igor1960igor1960 Solar Expert Posts: 85 ✭✭✭✭
    solar_dave wrote: »
    And Hardwired UL approved inverters do exist today! ;)

    Right, but my humble research was devoted to understanding, mostly for myself technical feasibility of those announcements:
    http://energy.gov/articles/energy-de...ems-homeowners
    http://energy.gov/articles/going-sol...ug-and-play-pv

    Bogus then?!
  • igor1960igor1960 Solar Expert Posts: 85 ✭✭✭✭
    Well some of us are not surprised at the results.

    Just imagine how much time would have been saved if only people would listen to begin with.

    Don't recall exactly when, but Einstein used to tell me that: Negative result is the result too. LOL
  • BB.BB. Super Moderators, Administrators Posts: 30,628 admin
    igor1960 wrote: »
    Right, but my humble research was devoted to understanding, mostly for myself technical feasibility of those announcements:
    http://energy.gov/articles/energy-de...ems-homeowners
    http://energy.gov/articles/going-sol...ug-and-play-pv

    Bogus then?!

    Both are:
    Through the Plug and Play Photovoltaics Funding Opportunity Announcement (FOA), the Department of Energy will invest up to $25 million over five years to advance the development of a commercial plug-and-play photovoltaic system, which is envisioned as an off-the-shelf product that is fully inclusive with little need for individual customization. Homeowners can install the system without special training or tools. The homeowner simply plugs the system into a PV-ready circuit and an automatic PV discovery process initiates communication between the system and the utility.

    So--Dedicated PV ready circuit... All this is doing it the "notification" to the utility (and by extension, the local government entities). Interesting--But not "plug and play" as the average homeowner would understand to an existing arbitrary branch circuit--And still nothing about the consumer climbing on a second story roof and installing+wiring up solar panels. Could also integrate charging and grid tie operation for electric vehicles (car charges at night, and if plugged in, can support the utility on hot summer afternoons--another set of questions about cycling costs of batteries, billing, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • igor1960igor1960 Solar Expert Posts: 85 ✭✭✭✭
    BB. wrote: »
    Interesting--But not "plug and play" as the average homeowner would understand to an existing arbitrary branch circuit--And still nothing about the consumer climbing on a second story roof and installing+wiring up solar panels. Could also integrate charging and grid tie operation for electric vehicles (car charges at night, and if plugged in, can support the utility on hot summer afternoons--another set of questions about cycling costs of batteries, billing, etc.).

    Bill, so exactly my point: what would stop consumer into pluging this P&P inverter into any existing outlet? So, there must be protection inside this "P&P inverter" against such case. We didn't find any. So, Energy Department idea is bogus then?
    I'm contemplating giving up on possiblity of such protection. However, the only way I do see is: on the site of P&P inverter, when P&P inverters current crosses 0 (meaning no Production output from inverter), check voltage level in Neutral and L1 => they should be 0 or in the opposite phases. The reason behind this is that any P&P inverter would have PF not equal 1, therefore inverters current is shifted a little bit relative to voltage in L1/Neutral, Right? Then if we do check this voltage at production current equal 0 and there is LOAD somewhere on the circuit (load current would be shifted in phase to production current), then we should see that Neutral/L1 voltage are in phase with each other.
    But the problem is: LOAD could also possibly have reactive current, shifted the same way as PRODUCTION current relative to voltage. Also, there might be more then one P&P inverters on the circuit, and as each would have it's own PF, cross of 0 current on each would not be synchronized with each other, so looking from inside of one inverter, we have no clue that there is remaining equal LOAD and other Production exactly equal in phase, but opposite in direction.
  • BB.BB. Super Moderators, Administrators Posts: 30,628 admin
    Again: "The homeowner simply plugs the system into a PV-ready circuit and an automatic PV discovery process initiates communication between the system and the utility."

    As simple as a new "non-standard" plug on a dedicated PV Circuit (with a registered interface box that wifi's to Internet or ZigBee utility communications shared with your "smart meter", or power line communications with routers on the power poles--who knows)... But when you get the DOE and government involved, there is no "simple" plug--It will be a "smart plug":

    The SAE J1772 charging plug is as inelegant as its name. And the five ports that connect to your car might seem complicated, but they're actually pretty straightforward.

    Attachment not found.

    1 AC power, just like the power plug for your TV.
    2 Proximity detection. This is simply a mechanical switch that makes sure you're plugged in all the way.
    3 Ground wire.
    4 Communications, used to relay data between the car and the charger about how much current is needed.

    How did humanity survive the 2 and 3 prong plugs...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bill von novakbill von novak Solar Expert Posts: 891 ✭✭✭✭
    igor1960 wrote: »
    Bill, so exactly my point: what would stop consumer into pluging this P&P inverter into any existing outlet?

    Special outlet.
    So, there must be protection inside this "P&P inverter" against such case. We didn't find any.

    It's outside the inverter.
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