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  • #31
    Originally posted by ButchDeal View Post
    I would hope that no one has an installation like yours as it is not the recommended way to install. Grid tie inverters should always be upstream of any transfer switch. Bimodal systems are a different story altogether.
    Furthermore why would you want to risk it?
    Tying into the poco side of a transfer switch is fail safe.

    Any change in load will cause a generator ( well most not including inverter type) to change frequency.
    This in theory should shut the inverter down but still not worth the risk.
    NABCEP certified Technical Sales Professional

    [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

    [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

    [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

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    • #32
      I would like to get my hands on an electrical diagram which shows all the elements in their proper positions. Are there diagrams available on this forum from anyone?

      Thanks, Glenn

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      • #33
        Originally posted by GlennT View Post
        I would like to get my hands on an electrical diagram which shows all the elements in their proper positions. Are there diagrams available on this forum from anyone?

        Thanks, Glenn
        Many things go into a "system schematic" and few installs are the same. So, if you can be more specific, are you looking simple grid tie? Grid tie with transfer relay and generator backup? Grid tie with transfer relay and hybrid inverter & generator backup?

        When you decide, I'll move your question to it's own thread, and not hijack this one.
        Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
        || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
        || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

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        • #34
          Originally posted by Mike90250 View Post
          Many things go into a "system schematic" and few installs are the same. So, if you can be more specific, are you looking simple grid tie? Grid tie with transfer relay and generator backup? Grid tie with transfer relay and hybrid inverter & generator backup?

          When you decide, I'll move your question to it's own thread, and not hijack this one.
          Thanks. I'll tell you what I've got here. Right next to the new Net Meter just installed by the utility is the Transfer Switch for the 20 kW Generac. When power fails, the switch connects the generator to my main panel in the house. On that panel is a 40 amp DP CB that feeds a 110 ft underground wire (#8AWG) to 100 amp subpanel in my barn. (The solar panels are mounted on my barn because it had a better roof with no shading issues.) On this subpanel is a 35 amp DP CB which connects the AC output of the SolarEdge 6000 GT inverter.

          I'm not familiar with "transfer relay", or understand what that does.

          My electrician is under the impression that my system, as I described it above, is safe and will work. He doesn't think the inverter will try to feed power onto the system if the generator is supplying power.

          If you can recommend a "fix" for my system, I'd love to hear it.

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          • #35
            Originally posted by GlennT View Post
            Ok, but are you speaking from experience, or conjecture? I would like to have someone chime in who's actually had an installation like mine and see what they discovered. Thanks for your input.
            You are not going to get an answer because it does not meet any code requirements and will not pass inspection. That means it is NOT SAFE.
            MSEE, PE

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            • #36
              Originally posted by Sunking View Post
              You are not going to get an answer because it does not meet any code requirements and will not pass inspection. That means it is NOT SAFE.
              Well, I have been forthcoming on my system and asked for recommendations on how to fix it. Will I have to run another set of wires from my AC disconnect in the barn to tie into the system on the "grid side" of the transfer switch at the house? It's already passed inspection. I just want to make it safe. Please help?

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              • #37
                Originally posted by GlennT View Post
                My electrician is under the impression that my system, as I described it above, is safe and will work. He doesn't think the inverter will try to feed power onto the system if the generator is supplying power.
                It will certainly try. If the voltage and frequency are stable enough it will succeed. It depends on the inverter and generator.
                If you can recommend a "fix" for my system, I'd love to hear it.
                Simplest way is to move the barn branch circuit to a place upstream of the transfer switch.

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                • #38
                  Originally posted by GlennT View Post
                  Well, I have been forthcoming on my system and asked for recommendations on how to fix it. Will I have to run another set of wires from my AC disconnect in the barn to tie into the system on the "grid side" of the transfer switch at the house? It's already passed inspection. I just want to make it safe. Please help?
                  The only way to make the installation safe and code compliant is to do whatever is necessary in terms of running more wires so that your GTI is connected at the POCO side of the transfer switch. This might even involve installing a new disconnect box near the meter if your POCO does not allow line side interconnections to their service wiring.

                  If the transfer switch has auxiliary signalling/control contacts you could use those contacts to open a relay in the barn that disconnects the GTI from the house wiring completely. If properly done that might be safe, but I am pretty sure it would not meet code.

                  The simplest "fix" without running additional wires to the barn is to move the entire barn feeder circuit to the POCO side of the transfer switch. This would again involve adding a new disconnect and is work that should only be done with a permit by a licensed electrician. It would involve having POCO pull the meter so that the work would not be done on hot conductors. (Prohibited by OSHA.)

                  So in both cases (added wire or moved feeder) the biggest problem that an electrician will face is how to provide a place on the POCO side of the transfer switch to which the GTI or the entire barn can be connected.
                  SunnyBoy 3000 US, 18 BP Solar 175B panels.

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                  • #39
                    I have run into this situation before on a boat house. The generator and house were 200 feet away and the generator had to feed the boat house for deicing equipment.
                    The simplest and easiest was to install a radio control contactor in the boat house that the transmitter was set to keep the contactor on unless power to the transmitter was turned off
                    Simple to do by tying the transmitter to the poco side of the transfer switch.

                    Big question i have is how many solar installs has your electrician done and how many had a generator and whole house transfer switch.
                    NABCEP certified Technical Sales Professional

                    [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                    [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                    [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

                    Comment


                    • #40
                      Originally posted by inetdog View Post
                      If the transfer switch has auxiliary signalling/control contacts you could use those contacts to open a relay in the barn that disconnects the GTI from the house wiring completely. If properly done that might be safe, but I am pretty sure it would not meet code.
                      Issues like this make me wish that grid tie inverters had a somewhat standardized enable/disable input. I know some foreign markets require them to allow throttling of generation during times of low demand, but they would also help in cases like this. (And of course would help in AC coupled systems.)

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                      • #41
                        Thanks everyone for all the helpful advice. I will take all this to my electrician and see what we can come up with.

                        Thanks again.

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                        • #42
                          Originally posted by GlennT View Post
                          Thanks everyone for all the helpful advice. I will take all this to my electrician and see what we can come up with.

                          Thanks again.
                          Sounds like the best course of action.
                          Many competent residential electricians who do not yet have any experience with solar take awhile to get up to speed on the unfamiliar ins and outs of GTIs and the NEC provisions related to them.
                          SunnyBoy 3000 US, 18 BP Solar 175B panels.

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                          • #43
                            Pictures of blown generator rotor. This rotor came out of a 14 kw generac generator. The generator was already installed when the solar company installed a 5kw grid tied system. Solar connection was made through a two pole breaker in the main circuit breaker panel. IE: tied in after the automatic transfer switch.

                            IMG_1558.JPGP IMG_1557.JPG
                            Attached Files

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                            • GlennT
                              GlennT commented
                              Editing a comment
                              Great pictures! Thanks for the feedback regarding this issue. I had the electrician who originally installed my generator to come back and install a separate switch for the grid tied inverter to the utility side of the transfer switch, as was advised by several on this forum. Now, when the utility power is lost, the generator starts and powers the home, and the inverter remains unpowered and offline. Thanks again for all who offered help on my project. I learned a lot.

                          • #44
                            Definitely the wrong thing to do!
                            SunnyBoy 3000 US, 18 BP Solar 175B panels.

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                            • #45
                              I want to try to balance the load and see if it works. My AC pulls about 3500 watts. What if I turn on the solaredge when is producing less than 3000 watts?

                              Comment


                              • ButchDeal
                                ButchDeal commented
                                Editing a comment
                                your generator, your money, take a video so other can learn.

                                If it works at all, it is like buying hand grenade but not getting the pin because you can hold it; sooner or later there will be a problem.
                                Last edited by ButchDeal; 07-22-2016, 05:05 PM.
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