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Hello - I'm new to this forum and am reaching out because I have a major unresolved problem with my on-grid home PV installation. I have a 36 panel 11.9kW DC/10kW AC array rack-mounted about 200 ft from my house. The schematic shows two strings of JASolar JAP72S01 panels with a Solar Edge single phase HD Wave inverter mounted beneath the panels. It went live in December, 2018. Installation was by Midwest Wind and Solar, which is no longer in business.
In a nutshell, the problem is that voltage creeps up with PV power production leading to inverter shut-down. Solar Edge says the inverter is working properly, the power company says that they are providing (relatively) clean voltage and the (new) installer says that the installation is wired correctly.
Symptoms are as follows: voltage before system wake-up is 250v, with minor variation. With system wake-up voltage at the inverter climbs with power production. When voltage reaches around 260v the inverter shuts down and voltage drops back to 250v.
I didn’t notice anything amiss until September, 2021 when I got an unexpected power bill. When I looked at the Solar Edge monitoring data, power production starts to noticeably drop first in March, 2021 and I thought that the problem started around then. I opened up a support case with Solar Edge and it escalated to Tier 3 but in the end they said the inverter is working alright. They suspect installation, but can't say in what way. As Solar Edge pointed out the voltage creep/"grid voltage" problem has been there all along, its just been getting worse. I reviewed the historical monitoring data and in 2020 the voltage frequently exceeded 260v but without the inverter shutting down. The shut-downs I did notice were when power production hit the 10kW limit. Now it shuts down at 260v or less, and for longer. For example, on 10/1/22 the inverter was shut down between 10:44 and 16:28.
A review of monthly production is interesting and may provide some clues. Production Nov.-Feb. seems to be normal with random variation between all four years of operation. March-Oct., however shows a systematic reduction in power production for 2021 and 2022 compared to the prior two years.Monthly production for these two most recent years is down 10 to 50%. There is one interesting anomaly, July 2022. Looking day-by-day at AC power and voltage graphs I see fewer shutdowns, more stretches when the system appears to be behaving normally. I don't know what to make of these observations, except that there may be a connection with load. I have a geothermal system for heat and air conditioning. It draws a lot of power during cool months and when I run the air conditioning. The location is in southwestern Michigan and with proximity to Lake Michigan we seldom use air conditioning. I cannot correlate my house electrical power consumption with the inverter shutdowns but I do know that last July was uncommonly hot and humid and as a consequence we ran the air conditioning much more than usual. I am neither trained nor experienced in these matters, but I am suspicious of the inverter power management settings, specifically reactive power management.
The power company, Indiana/Michigan Power, has been quite cooperative. Their troubleshooter has been onsite several times. In December, 2021 he put a data logger on my meter to record voltage being supplied. It recorded normal levels of variation, never exceeding 127v. (I have copies of the log and supplied them to Solar Edge.) They checked grounding, reset their local regulator and re-crimped the house connections to the grid.
The new Solar Edge authorized installer sent their master electrician onsite. He verified that the wire is #6 and appropriate, and that the rest of the installation is alright. He thinks that the problem is with the ground/neutral of the grid connection to the house. Re-crimping the connections, however, did not solve the problem. Solar Edge, as mentioned above, thinks that the grid supply is OK and that there must be something wrong with the installation but the master electrician said that the installation is fine. Solar Edge has washed their hands of the problem and I am left with what amounts to a $30,000 lawn ornament.
I would be very grateful for any insight this community could provide.
Tom Reepmeyer
In a nutshell, the problem is that voltage creeps up with PV power production leading to inverter shut-down. Solar Edge says the inverter is working properly, the power company says that they are providing (relatively) clean voltage and the (new) installer says that the installation is wired correctly.
Symptoms are as follows: voltage before system wake-up is 250v, with minor variation. With system wake-up voltage at the inverter climbs with power production. When voltage reaches around 260v the inverter shuts down and voltage drops back to 250v.
I didn’t notice anything amiss until September, 2021 when I got an unexpected power bill. When I looked at the Solar Edge monitoring data, power production starts to noticeably drop first in March, 2021 and I thought that the problem started around then. I opened up a support case with Solar Edge and it escalated to Tier 3 but in the end they said the inverter is working alright. They suspect installation, but can't say in what way. As Solar Edge pointed out the voltage creep/"grid voltage" problem has been there all along, its just been getting worse. I reviewed the historical monitoring data and in 2020 the voltage frequently exceeded 260v but without the inverter shutting down. The shut-downs I did notice were when power production hit the 10kW limit. Now it shuts down at 260v or less, and for longer. For example, on 10/1/22 the inverter was shut down between 10:44 and 16:28.
A review of monthly production is interesting and may provide some clues. Production Nov.-Feb. seems to be normal with random variation between all four years of operation. March-Oct., however shows a systematic reduction in power production for 2021 and 2022 compared to the prior two years.Monthly production for these two most recent years is down 10 to 50%. There is one interesting anomaly, July 2022. Looking day-by-day at AC power and voltage graphs I see fewer shutdowns, more stretches when the system appears to be behaving normally. I don't know what to make of these observations, except that there may be a connection with load. I have a geothermal system for heat and air conditioning. It draws a lot of power during cool months and when I run the air conditioning. The location is in southwestern Michigan and with proximity to Lake Michigan we seldom use air conditioning. I cannot correlate my house electrical power consumption with the inverter shutdowns but I do know that last July was uncommonly hot and humid and as a consequence we ran the air conditioning much more than usual. I am neither trained nor experienced in these matters, but I am suspicious of the inverter power management settings, specifically reactive power management.
The power company, Indiana/Michigan Power, has been quite cooperative. Their troubleshooter has been onsite several times. In December, 2021 he put a data logger on my meter to record voltage being supplied. It recorded normal levels of variation, never exceeding 127v. (I have copies of the log and supplied them to Solar Edge.) They checked grounding, reset their local regulator and re-crimped the house connections to the grid.
The new Solar Edge authorized installer sent their master electrician onsite. He verified that the wire is #6 and appropriate, and that the rest of the installation is alright. He thinks that the problem is with the ground/neutral of the grid connection to the house. Re-crimping the connections, however, did not solve the problem. Solar Edge, as mentioned above, thinks that the grid supply is OK and that there must be something wrong with the installation but the master electrician said that the installation is fine. Solar Edge has washed their hands of the problem and I am left with what amounts to a $30,000 lawn ornament.
I would be very grateful for any insight this community could provide.
Tom Reepmeyer
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