So, we got a great deal on a punch of new Hanwha panels. The nameplate rating is 600V. We were hoping to use them on a commercial system with a 1000V inverter. At first, it was obvious, this wouldn't work. You can't exceed the panels maximum system ratings, but as we dug deeper, I have started to question this and was curious on opinions.
We asked Hanwha what physical differences were between the newer model panel given 1000V rating when 1000v ratings started to become commonplace. They mentioned they switched backsheet materials for further dielectric improvments after getting their new UL1703 rating for 1000V, but otherwise, nothing changed. All other hardware is completely identical.
After looking through the UL1703 and IEC 61215 tests for dielectric insulation, we found some puzzling things.
The UL tests require the insulation be tested at twice the system voltage + 1000V and no more than 50 microamps current flow. The IEC 61215 tests require 4 times the system voltage + 2000V with no more than 50 microamps current flow. These ratings are supposed to be baseline for safety. Why exactly is the IEC rating requiring more than double the hipot withstand voltage from UL? Is there even any science behind this? How can one panel be safe being tested at 2200V UL and then 4800V for IEC. Are these tests just arbitary? All other conditions are the virtually identical (damp heat, immersion test, test time, number of tests, etc).
Basically, this means a 600V rated panel tested under IEC standards would pass UL standards at well over 1000V. Conversely, a panel could fail in IEC standards, but be considered safe in UL standards. Everything I read on dielectric testing for panels is basically just guessing based on transient voltages from AC systems and then they revise these tests on what they actually see in the field. Why should these tests even be given any validation if the testing parameters are so drastically different?
Lastly, NIST ended up doing tests on breakdown voltages for dielectric backsheets. A TPT backsheet 0.29mm thick is consistently capable of withstanding well over 50 kV before breaking down.
https://www.nist.gov/sites/default/f...Ake-Sultan.pdf
My inspector said he is cool with us using the 600v panels at 1000V given this information. What do you guys think. Are these voltage ratings just political in nature?
We asked Hanwha what physical differences were between the newer model panel given 1000V rating when 1000v ratings started to become commonplace. They mentioned they switched backsheet materials for further dielectric improvments after getting their new UL1703 rating for 1000V, but otherwise, nothing changed. All other hardware is completely identical.
After looking through the UL1703 and IEC 61215 tests for dielectric insulation, we found some puzzling things.
The UL tests require the insulation be tested at twice the system voltage + 1000V and no more than 50 microamps current flow. The IEC 61215 tests require 4 times the system voltage + 2000V with no more than 50 microamps current flow. These ratings are supposed to be baseline for safety. Why exactly is the IEC rating requiring more than double the hipot withstand voltage from UL? Is there even any science behind this? How can one panel be safe being tested at 2200V UL and then 4800V for IEC. Are these tests just arbitary? All other conditions are the virtually identical (damp heat, immersion test, test time, number of tests, etc).
Basically, this means a 600V rated panel tested under IEC standards would pass UL standards at well over 1000V. Conversely, a panel could fail in IEC standards, but be considered safe in UL standards. Everything I read on dielectric testing for panels is basically just guessing based on transient voltages from AC systems and then they revise these tests on what they actually see in the field. Why should these tests even be given any validation if the testing parameters are so drastically different?
Lastly, NIST ended up doing tests on breakdown voltages for dielectric backsheets. A TPT backsheet 0.29mm thick is consistently capable of withstanding well over 50 kV before breaking down.
https://www.nist.gov/sites/default/f...Ake-Sultan.pdf
My inspector said he is cool with us using the 600v panels at 1000V given this information. What do you guys think. Are these voltage ratings just political in nature?
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