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Lost microinverters due to power surge. How common is that?

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  • #16
    Originally posted by khanh dam View Post

    so enphase doesnt' stand behind their product. Why the hell does the grid going on/off line several times make their warranty invalid?
    why the heck is it the installers problem?
    nothing makes sense to me!
    To tell you the truth, that's exactly what we think. It doesn't make sense at all that the microinverters cannot take a power surge or why some kind of protection wasn't included in the installation.

    It is not the installers problem, they referred us to the installer to get the microinverters replaced, at our cost of course.

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    • #17
      I mess with larger power systems on occasion for combined heat and power systems in predominantly Massachusetts. I am not aware of any rules or regulations that utilities are required to keep transient power quality data and make it available to the public. I seriously doubt that it would be practical or very useful. On my NH system when I applied for permission to connect my grid tied system I had to sign a contract fairly standard agreement that I would hold harmless the utility for any potential damage introduced from the utility system into my system.

      Generally if there is suspicion that the utility has power quality issues, they send a tech out and temporarily install a power quality analyzer hooked up the voltage and current transducers that are connected to their metering. They leave it a few weeks and then analyze the data to prove or disprove the problem. If its on their end, they chase it down and fix it and frequently do not talk about the fix. On the other hand if they think it may be from inside the customers system they will throw it back on the customer. In most cases the 13,8 KV systems we are installing and monitoring are behind at least one set of transformers at the utility substation and transformers can dampen out transmission issues and cause local issues on the circuit to propagate. One thing that many folks learn with power quality issues is that its usually a combination of separate issues and its just as likely the issues are inside the owners plant. Power factor correction capacitors can be a real problem, Most banks are either on or off and how they are controlled may cause power quality issues even though they are keeping the power factor within an acceptable range. Switched mode power supplies also can cause lots of issues. They can generate a waveform that looks like a AC sign wave but interposed on the sine wave are highly level harmonics that can randomly(and not so randomly) synchronize and generate short term blips that are two fast for conventional metering to pick up but enough to fry poorly isolated electronics. Good practices to isolate an electronic device costs money and in a competitive environment where a firm like Enphase was losing money on every inverter they built in hopes of eventually turning a profit, the easy way out is to go cheap and hide behind a warranty.

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      • #18
        I have seen cases where our local utility paid for damage caused by power "surges". It was a very clear case though with lots of damage and refrigerators, etc in the same neighborhood all died at the same time...
        We choose not to install microinverters precisely because they are too hard to service.
        BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installed

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        • #19
          Originally posted by peakbagger View Post
          I mess with larger power systems on occasion for combined heat and power systems in predominantly Massachusetts. I am not aware of any rules or regulations that utilities are required to keep transient power quality data and make it available to the public. I seriously doubt that it would be practical or very useful. On my NH system when I applied for permission to connect my grid tied system I had to sign a contract fairly standard agreement that I would hold harmless the utility for any potential damage introduced from the utility system into my system.

          Generally if there is suspicion that the utility has power quality issues, they send a tech out and temporarily install a power quality analyzer hooked up the voltage and current transducers that are connected to their metering. They leave it a few weeks and then analyze the data to prove or disprove the problem. If its on their end, they chase it down and fix it and frequently do not talk about the fix. On the other hand if they think it may be from inside the customers system they will throw it back on the customer. In most cases the 13,8 KV systems we are installing and monitoring are behind at least one set of transformers at the utility substation and transformers can dampen out transmission issues and cause local issues on the circuit to propagate. One thing that many folks learn with power quality issues is that its usually a combination of separate issues and its just as likely the issues are inside the owners plant. Power factor correction capacitors can be a real problem, Most banks are either on or off and how they are controlled may cause power quality issues even though they are keeping the power factor within an acceptable range. Switched mode power supplies also can cause lots of issues. They can generate a waveform that looks like a AC sign wave but interposed on the sine wave are highly level harmonics that can randomly(and not so randomly) synchronize and generate short term blips that are two fast for conventional metering to pick up but enough to fry poorly isolated electronics. Good practices to isolate an electronic device costs money and in a competitive environment where a firm like Enphase was losing money on every inverter they built in hopes of eventually turning a profit, the easy way out is to go cheap and hide behind a warranty.
          You are correct. Certain "loads" will cause all type of harmonic issues. Power factor caps tend to increase the 11th harmonic while Switch mode power supplies can increase all of the "tripline" harmonics 3rd, 9th, 15th etc. While solid state motor drives increase the 5th and 7th harmonic. The biggest problem is with the triplines which can increase the amount of current on the neutral wire beyond what it can handle.

          For the utility any Y / Y transformers will allow harmonics to pass back and forth on the Neutral wire. A Delta / Y transformer seems to stop the harmonics, but any power grid that uses a Y / Y can pass bad harmonics from one customer to another on the same power circuit.

          Oh by the way, a large solar grid tied inverter can generate harmonics that go out to the grid and can cause issues to other customers on that circuit.

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          • #20
            Question: Will a solar installer work on a installation done by a different company? Are there some liability issues? I'm in NH.

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            • #21
              After reading this thread, it go me thinking about my install, which is Solar Edge/DC Optimizer based. After navigating a few broken links you get to this page https://www.solaredge.com/sites/defa...protection.pdf. When you get about 1/2 down to page 3, you encounter the following text "The inverters are classified as having Type III (class D) protection (limited protection)." A little review of SPD/Overcurrent Devices:
              SPD Type 1 -- Service Entrance (AC would be on your Utility meter base)
              SPD Type 2 -- Main Panels (AC side would be in your main panel)
              SPD Type 3 -- Near Sensitive Loads

              The document talks a lot about Commercial Inverters/ 3 phase, but I am going to assume similar protection is required in residential inverters. On the Commercial Inverters evidently there are options to have built in SPD protection (https://www.solaredge.com/sites/defa...tion-guide.pdf). On the residential side, there are not built in options. As best I can tell, if your panels are at risk of an indirect strike, you need to add an external SPD Type 2 device. If a direct lightening strike is of concern, you need to add an external SPD Type 1 or Type 1+2.

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              • #22
                Years ago before I hardened my electrical system I cannot tell you how many times I went through battles with the power company over burned out equipment. Bottom line is I never got a dollar from them.

                A Master Electrician told me it works like this.

                1) If there is obvious damage in the area, like a tree falling down and hitting a light post and shorting out the power to ground, you will get paid for damages.

                2) If a section of your Neighborhood all had the same problem, you will get paid.

                3) If you have a commercial Power Data tracker that display voltage, current usage, phase and a few other relevant pieces of information and you get the power company to send an inspector over right after the incident and show them the damage plus give them a copy of the Data that shows a grid issue, you will get paid.

                He said anything outside of those three situations is a waste of time to try and get money out of them.

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                • #23
                  I have GE whole house surge protection, but all of you have convinced me that I need to do better. I have ordered a Midnight Solar Surge protector for my main power panel. My SMA inverter warranty does not include failure due to "force majeure". I'm glad we have such knowledgeable members on this forum. I am having work done on my main panel for ATS work anyway so it makes sense to make the upgrade to Midnight solar at the same time.

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                  • #24
                    The bummer with going with the "right" equipment is you never know when they saved you from a surge. Unless someone is doing continuous power monitoring, they will never know it.

                    One important thing for those working on the main panel to check is the quality of the household primary ground. Sometime shortcuts are taken when putting in the primary ground or it gets damaged over the years by folks digging around the house. There are some specialize testing devices that are supposed to be able to detect the quality of the ground. I am aware of that they exist but not sure what they are called.

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                    • #25
                      peakbagger , thanks for the advice. I have a 5 year old house with nobody digging around the primary ground. They are also putting more grounds in when I get the generator installed. I could get the ground tested, but I'm not quite at that point yet. Thanks!

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