Please help: THREE Phase installation with 3 inverter setup, - 3 phase with NO NEUTRAL

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Chan
Chan Registered Users Posts: 45 ✭✭
edited October 2016 in Solar Beginners Corner #1
Please help: THREE Phase installation with 3 inverter setup, - utility/grid only has 3 wire of which all 3 wires are LIVE wires.... there is no NEUTRAL.

How do I wire a 3 Phase inverter or 3 parallel inverter using only the L1 L2 L3 WITHOUT A NEUTRAL. WE DO NOT HAVE A NEUTRAL.3
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    You need an electrician
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #3
    You do need an electrician--But where is this going to be installed (Philippines?)?

    What is the voltage reading? (L1-L2; L1-L3, L2-L3)? And L1 to ground, L2 to ground, and L3 to ground.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 7,025 ✭✭✭✭✭✭
    #4
    Looks like a fire wating to happen. A knock-out without strain relief or even conductor protection. Get help!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Chan
    Chan Registered Users Posts: 45 ✭✭
    #5
    Philippine Wiring.
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  • Chan
    Chan Registered Users Posts: 45 ✭✭
    #6
    The problem lies with parallel inverter 3 phase is that we do not have neutral, This is common here in PH
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  • Chan
    Chan Registered Users Posts: 45 ✭✭
    edited October 2016 #7
    L1 - L2 = 220
    L2 - L3 = 220
    L1 - L3 = 220


    I do have similar problem with this thread:
    http://forum.solar-electric.com/discussion/11860/neutral-ground-inverter-wiring/


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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #8
    What are the gt inverters rated for (230 50hz or 230 60 hz or 120 60 hz)?

    If you have ~230 vac rated inverters, then connecting A to L1/L2, B to L2/L3, and inverter C to L3/L1... All else being done chiefly correctly (breakers/fuses, possibly phase drop protection, less than 10kw imbalance between phases, you have a full Wye or Delta transformer set, utility approval, etc.).

    Some inverters use a neutral to detect a broken neutral connection, but outside of north America, that usually does not apply/is not implemented (I.e., our split phase 120/240 vac system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Chan
    Chan Registered Users Posts: 45 ✭✭
    #9
    Inverter is a single PHASE
    http://www.goodwe.com.cn/product/show-615.aspx

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #10
    You need to get an installation manual for the inverter and programming informant.

    You would connect like your diagram,  except like I said,  inverter A 230 vac output to L1&L2, etc.

    Each inverter only sees a single phase (and follows that phase). They do not care about the other inverters on other passes.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Chan
    Chan Registered Users Posts: 45 ✭✭
    #11
    INVERTER

    http://www.goodwe.com.cn/product/show-615.aspx

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #12
    Found the downloads here:

    http://www.goodwe.com.cn/download/0.aspx

    And a user manual here:

    http://www.goodwe.com.cn/tools/download.ashx?id=273

    I believe you will need to contact the mfg with your installation needs. The standard user interface does not appear to allow an end user to program the specific details for your country's power requirements.

    It looks like if you want a smaller 3 phase installation, you would get 3x single phase GT inverters (less than 15 kWatt total solar array power). If you want 15 kWatt or larger, you can get three phase system GT inverter (one "box").

    I do not see anything that would "require" a ground bonded neutral (for example, in the US, both L1 and L2 are "hot"... L1-L2 are 240 VAC, and L1-ground (and neutral) is 120 VAC, and L2-ground (neutral) is 120 VAC)... In the US, Neutral is the center tap of a transformer that is bonded to earth/safety ground in the main panel.

    By the way, did you measure L1-ground; L2-ground; and L3-Ground? It can tell us a bit more about your three phase installation (Wye or Delta, and if any leads are ground referenced).

    In any case--It appears that the inverters are programmed at the factory for country specific requirements (frequency, actual high/low voltage range, etc.). You might get a programmer (or programming software and password) from the Mfg...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Chan
    Chan Registered Users Posts: 45 ✭✭
    #13
    This was sent to me by the manufacturer - a different company with 3 PHASE inverter.
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #14
    Been reading this and I'm a little confused as to what it is you are trying to achieve, more details such as want to run a 3 phase pump off solar. The 3 inverter method would not work as the inverters are electrically isolated from one another on the A B C legs and even if you connected one output leg to a common which theoretically could get you 3 phase, the output would most certainly be synchronized as they are not communicating with one another and more than likely cook the inverters through  back feeding...wouldn't try that method.

    The second diagram looks like an explosion. ...wouldn't try that either.

    In all likelihood you have a Delta feed, and if what you need is a solar system with such a feed there are 3 phase inverters available, but again, more details. Be safe
    Electrician here with 40 years experience 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #15
    Edit to last reply shold read.....theoretically could get you 3 phase, the output would most certainly be not be synchronized...
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #16
    Look up Cotek SD series inverter they can communicate with one another and give 3 phase.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #17
    Chan's drawing indicates he has a Wye system with 4 hots and a neutral (center tap)--The center tap may be grounded at the pole transformer (depends on what is done in Philippines). And he has a 208/400 per the drawing--But that does not really make sense.

    It has been many decades since I did three phase Wye math--But if the low line is 208 then the high should be (208*sqrt(2)=) 360 VAC, not 400 VAC.

    Chan, you said there is no neutral?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 7,025 ✭✭✭✭✭✭
    #18
    Chan is probably not having internet today with a super typhoon offshore of the Philipines.
    https://earth.nullschool.net/#current/wind/surface/level/equirectangular
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • wag123
    wag123 Registered Users Posts: 1 ✭
    edited October 2016 #19
    Three separate inverters won't work. They need to be in-phase (synchronized) with each other on a three phase system, and standard inexpensive inverters won't be. You are really going to need to look at a SINGLE three phase inverter that is specifically designed for this purpose (expensive). I'm not familiar with the Cotek SD series inverters.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #20
    If this is a grid tie/utility interactive system (no batteries, no off grid operation), then three single phase gt inverters (one one each phase) works fine.

    His utility may require all inverters to turn off if there is the loss of one or two phases.

    If off grid operation, three phase is a different animal.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #21
    Attached is the pdf for Cotek's SD inverter that can sync with one another, Bill is correct that it could  work bot a neutral would be raquired as a reference point for each inverter to synchronize with its respective phase, 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #22
    For three phase GT inverters, no neutral is required, unless the local power company/regulations require it (in US, our gt inverters typically connect to L1+L2, neutral is not required, but tested to be there. Inverter will shut down if the inverter lead is broken).

    A single phase inverter knows nothing about other phases and cannot sense then (if other Lx wire is not brought into said inverter). A GT Inverter simply follows the single phase sinewave voltage, and injects current proportional to the instantaneous voltage value (it can get more complex, but that is the basics).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #23
    Have read this thread numerous times and it's  still unclear to me at least, as to what Chan it trying to achieve, is it a grid tied, a stand alone 3 phase, or as the last drawing suggests some sort of a hybrid stand alone/ grid tied system. More details would be extremely helpful, interesting discussion none the less.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,696 admin
    #24
    One drawing is Grid Tied, the other is Backup/Hybrid (off grid capable)--Yea, it is not obvious, and may even be several different projects.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Chan
    Chan Registered Users Posts: 45 ✭✭
    #25
    Actually, the other (drawing diagram) comes from voltronic manufacturer, which they recommend the transformer if I DO NOT HAVE A NEUTRAL FOR A HYBRID-OFFGRID-GRIDTIE SETUP.
    http://www.voltronicpower.com/oCart2/index.php?route=product/product&product_id=141

    - BUT as for the GT, I am not worried as there is no need for a neutral. A GT setup is just .... l1+l2 / l2+l3 / l1+l3 will do... and any order or as many as you can attach to the GRID.

    - The problem lies when you need an OFF-GRID/HYBRID SETUP WITH A NEUTRAL. ** but I dont think ill think about this as of now... as I have talked with my utility company and they are willing to give me a neutral line should I needed one. (PHILIPPINES) does not need NEUTRAL LINE... as both L1 - L2 are LIVE.

    - any more / other input on this thread is very much appreciated


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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 7,025 ✭✭✭✭✭✭
    #26
    If you have not bought the hybrid inverters yet, you can buy hybrid inverters from Schneider, Outback & others that are 250VAC only and not have the neutral issue.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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