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

[Calsun]

As a practical manner how would one protect a dozen or more microinverters attached to solar panels mounted on a roof? Best to invest in a set of backup inverters so when one fails it can be quickly replaced. It is much easier to protect a single grid tie inverter.

[leaptrend]

Power surges can be a common cause of damage to electronic devices, including microinverters. However, the frequency with which power surges cause damage to microinverters can vary depending on a number of factors, such as the strength and duration of the power surge, the quality and age of the microinverters, and whether or not the microinverters were protected by surge protection devices.

In general, it is always a good idea to use surge protection devices to help protect your electronic devices from power surges. These devices can help to absorb excess voltage and prevent it from reaching your electronics, reducing the risk of damage from power surges. It is also a good idea to ensure that your microinverters are installed and maintained properly to help reduce the risk of damage from power surges and other sources.

[Calsun]

When I had the panels and inverter installed I also had the electrician install a "whole house" surge protector. These are cheap at less than $100 and the electrician was on site to install the inverter. We don't have electrical storms where I live, but power surges and power sags are a weekly occurrence.

[DanS26]

The gold standard is under meter Type 1 surge protection, something like this.........

https://kbelectricpa.com/whole-house-surge-protection-type-1-meter-based-surge-protector/

Some POCOs will allow you to install your own but most will want you to buy or lease a unit from them.

Also if you are in a high lightning strike area and you ask real nice the POCO may install an industrial SPD right on the transformer can at the pole or pad. Can't hurt to ask but get ready for sticker shock.

[peakbagger]

Whole house surge suppressors vary in quality and clamp voltage. Most folks just buy a brand they think is going to work. The old Delta can types were definitely only usefull for keeping the wiring into bursting into flames. Midnight Solar offers several clamp voltages including a 300 volt version that is set up for 240 volt panels. As Sunking stated on another thread, it can be crap equipment on the owners end but most good equipment will survive a surge that is clamped at 300 volts.

[Ampster]

That has always been my gripe with whole house surge protectors. They all will let up to 600V pass through. While they do help, in a worst case scenario this type of surge suppressor will only protect the wiring in the home and prevent it from melting in the walls and from starting a fire. That is important, obviously, but most people think they are totally safe and that their equipment is also fully protected. You have to install point-of-use surge protectors individually to protect specific devices in addition to the whole house device.

A friend lost a bunch of micros to a surge a few years ago. After that he recommended one of those whole house protecters that look like a circuit breaker and snap into the main service panel. I have about 30 micros that I want to protect so I will double check the specs on that protecter. My micros are on a subpanel that is fed on a passthrough connection from my hybrid inverter and will have to check to see how much protection it offers. During a power outage it did report an over voltage event and shut down. I just had to restart the hybrid inverter during the outage.

[solarintexas]

Last summer I had a lightening strike come through my aluminum fence, it got close enough to the downspout across the flashing and into the electric via the radon fan.

Did you have a whole home surge protector at the panel level? In our case, they paid for the homeowners deductible. Depending how big the surge is, in some cases you aren't going to stop it. In our case it traveled down the neutral wire and sheered all the insulation off of it. If you look at most of the whole home surge protectors they still allow quite a bit of voltage through. In many cases 600v+ is let through.

If I am following, Enphase denied the claim because there was bad weather in the vicinity? What is Enphase's recommendation for surge protection?

That has always been my gripe with whole house surge protectors. They all will let up to 600V pass through. While they do help, in a worst case scenario this type of surge suppressor will only protect the wiring in the home and prevent it from melting in the walls and from starting a fire. That is important, obviously, but most people think they are totally safe and that their equipment is also fully protected. You have to install point-of-use surge protectors individually to protect specific devices in addition to the whole house device.

[Whyguy]

If I am following, Enphase denied the claim because there was bad weather in the vicinity? What is Enphase's recommendation for surge protection?

The Enphase warranty for both the US and Australia (and presumably everywhere) specifically excludes any damage from lightning. Interestingly, Enphase recommends (but does not require) lightning protection using surge protection devices for its Australia customers (https://www4.enphase.com/sites/defau...Protection.pdf) but is silent for its US customers. This is probably because Australia follows the European Community lighting protection approach (BS EN/IEC 63205) which is quite detailed and technical. The US approach is less detailed and pretty much up to the property owner. The National Electric Code (NFPA 70) only refers to lightning protection at sections 250.60, 250.106, and 820.44(E)(3), in informational notes which are not enforceable. These in turn refer to NFPA 780, “Standard for the Installation of Lightning Protection Systems”. Unless Authorities Having Jurisdiction (AHJs, such as city building departments) have specifically adopted NFPA 780 along with the NEC, they can’t enforce it.

Given this, the Enphase legal department probably decided it was better not to give US customers specific guidance.

[oregon_phil]

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!

[peakbagger]

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.

[oregon_phil]

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.

[robbyg]

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.

[heimdm]

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.

[casan]

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

[SunEagle]

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.