Announcement

Collapse
No announcement yet.

Large-Scale installation Single-Line Electrical diagram

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Large-Scale installation Single-Line Electrical diagram

    Hi everyone,

    I am a junior engineer in charge to design a 1MW solar PV plant for a feseability study. I found this forum and I hope some of you could give me a hand with a couple of enquiries I have.
    Of course, my design will be assessed and improved by another experienced solar engineer. But I want to do my best and prove that I can be worthy for the company.

    The installation is divided in 50 inverters of 20 kW each, 16 strings for each inverter and 8 modules for each string.
    My main concern is how it is the connection of 50 inverters in a single transformer of 1250 kVA. Could you explain me that? I tried to find some scheme without success.

    Additionaly, I am enclosing the electrical scheme because I am not sure about the required protections, consequently any comment or feedback would be highly appreciated.

    Please, find attached the single-line electrical diagram.

    Thanks,hopefuly some of you can help me and I also can contribute to the forum in a near future.
    Attached Files

  • #2
    That's above my pay-grade, sorry.
    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

    Comment


    • #3
      I will make one comment and then let the experts chime in.

      At that size system I would expect the inverters and main transformers to be 3 phase and not single phase as your single line represents.

      Good luck on your project.

      Comment


      • #4
        SunEagle is correct. That would definitely be a 3 phase system.
        As for combining inverters, you will likely have custom built high voltage combiner cabinets.

        Comment


        • #5
          Is this a joke.

          Tell you what, for $50K I will educate you. Consider it a Consultation fee. No one is going to answer your question, and it will never happen. No engineer is going to use consumer grade toy Inverters to build a commercial system. If you were my employee I would fire you on the spot for incompetence and write your school a nasty letter for letting an idiot graduate.

          Here is a clue, it only takes 3-Inverters. Figure it out or hire someone who knows what they are doing. You are a joke. Please tell us who your boss is so we can direct his attention to this thread. You will be unemployed tomorrow. .

          MOD's lock this thread so this idiot cannot delete his thread and hide.
          Last edited by Sunking; 11-08-2016, 12:46 PM.
          MSEE, PE

          Comment


          • #6
            First of all, are three phase inverters as the diagram shows. It is call single line diagram because it shows all phases in one line. If you look at cabling you can see a 2 for DC and then three at AC for three phase.

            Then, the person who is directly insulting me. I would ask him please why it would be enough with three inverters? The plant has to generate 1 MW and we are forced to use 20 kW inverters due to the location and maintanence issues. With three inverters the plant wouldn't produce enough power.

            Comment


            • #7
              Originally posted by Apellidos View Post
              First of all, are three phase inverters as the diagram shows. It is call single line diagram because it shows all phases in one line. If you look at cabling you can see a 2 for DC and then three at AC for three phase.

              Then, the person who is directly insulting me. I would ask him please why it would be enough with three inverters? The plant has to generate 1 MW and we are forced to use 20 kW inverters due to the location and maintanence issues. With three inverters the plant wouldn't produce enough power.
              No the diagram does not show 3 phase inverters or a 3 phase 1000kva transformer because the amp values shown are for single phase.

              Who ever made that drawing needs to go back to school and learn some basic electrical math.

              Comment


              • #8
                You are Right, ampers calculation is monophasic.

                Comment


                • #9
                  Schneider Electric hides this stuff, but they have inverters from 6Kw wall boxes to Megawatt trailers.
                  http://solar.schneider-electric.com/...v-power-plant/ and one line sketches
                  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

                  Comment


                  • #10
                    Is "Vmppt" typically used for the AC voltage?
                    I wouldn't think so.
                    and it's labeled 230V instead of 480V (I'm guessing it would be 480V or maybe higher for this large of a system)

                    The plant has to generate 1 MW and we are forced to use 20 kW inverters due to the location and maintanence issues. With three inverters the plant wouldn't produce enough power


                    I would think maintenance would be better to have fewer but larger inverters. If it's three 333kW inverters or fifty 20kW inverters I would think you get the same power output And I would guess cheaper to go with fewer larger inverters since some of the overhead items eliminated. (ex. the case for a single inverter would be bigger, but there would be less metal needed for the bigger one because it wouldn't take as much space as all the smaller ones. )

                    Comment


                    • #11
                      This has to be the funniest thing I have ever seen on here... vmppt voltage ratings on a transformer...50 inverters... 25ka breakers downstream of 1mva transformer with no switchgear or protection... Searching google is NOT engineering. You obviously lied on your resume/cv. Where do you work? I might apply as they will need someone to complete your project.

                      Comment


                      • #12
                        I just can say I am sorry for the people who is offended. This is not my field and I am trying to learn by myself, I got a job because of other skills, but this is small company and they assigned to me the previous design of the plant, I am researching about the electrical connections because I am interested on it.
                        I recognise such a project can't be carry out for an unexperienced guy like me, I just trying to learn and that was my idea when I registred in this forum.

                        I see how far I am for doing something positive, I will search for a good book for large.scale plants and go deep in it the following days.

                        Comment


                        • Apellidos
                          Apellidos commented
                          Editing a comment
                          If anyone could recommend me a book or online course that can really help me I would much appreciate it.

                          I just would like to add, that in developing countries I see other !MW projects with 20kW inverters, and for this specific case they are forcing us to reject central inverters. For your peace of mind, I already informed my boss about the lack of knowledge in this field of all employees, the company has a design made by a solar module provider, and they just want to have an alternative design. I got it, better subcontract someone, but I would like to learn about it.

                          Sorry again, it was not my intention to offend your collective and I respect and agree all reviews, except the one who suggested my boss to fire me, when actually would be his fault to assign me this task, I tryed to do my best, but better stop before I am wasting more time and learn for the next time.

                      • #13
                        Originally posted by Apellidos View Post
                        Sorry again, it was not my intention to offend your collective and I respect and agree all reviews, except the one who suggested my boss to fire me, when actually would be his fault to assign me this task, I tryed to do my best, but better stop before I am wasting more time and learn for the next time.
                        I suppose a valid case could be made for replacing your boss as well. Maybe the whole operation needs an enema.

                        Comment


                        • #14
                          Originally posted by Apellidos View Post
                          Then, the person who is directly insulting me. I would ask him please why it would be enough with three inverters?
                          You are using toys made for consumers. Commercial and Industrial Inverters range in size from 10KW to 10MW, all custom built for the application.

                          Based on your responses and terminology, it is very clear neither you or your company has any experience. That is not an Insult, that is a FACT. You have not offended us, you have entertained us with your ignorance. At most If anything you scare us. .

                          There are no books to read or videos to watch. This is not an off the shelf plug-n-pray application. It takes years of experience under direct supervision of experienced engineers who have done it for 10 or more years. Just like heart surgery, there are no How-To books or videos. Just like colege, when you graduate, you are not qualified to do anything and most of what you were taught is just academic and has no application. School just gives you the tools you need to learn a profession on your own. If you fail, then you teach or go into politics.
                          Last edited by Sunking; 11-09-2016, 01:26 PM.
                          MSEE, PE

                          Comment


                          • #15
                            Originally posted by Sunking View Post
                            You are using toys made for consumers. Commercial and Industrial Inverters range in size from 10KW to 10MW, all custom built for the application.

                            Based on your responses and terminology, it is very clear neither you or your company has any experience. That is not an Insult, that is a FACT. You have not offended us, you have entertained us with your ignorance. At most If anything you scare us. .

                            There are no books to read or videos to watch. This is not an off the shelf plug-n-pray application. It takes years of experience under direct supervision of experienced engineers who have done it for 10 or more years. Just like heart surgery, there are no How-To books or videos. Just like colege, when you graduate, you are not qualified to do anything and most of what you were taught is just academic and has no application. School just gives you the tools you need to learn a profession on your own. If you fail, then you teach or go into politics.
                            I comprehend what you said and I totally agree with your second paragraph, and it is the reason why I am questioning my continuity in this company where I just can learn by my own, because there are no technical experienced employees, When I asked about books or courses, it is because I need foundations and it is not easy to find information about large-scale plants, maybe a should focus directly in electricity.

                            I don't regret about my initial post, But they shouldn't fire me, I should quit.

                            Comment

                            Working...
                            X