Maine's Solar Commerical Interconnect "disaster"

[peakbagger]

https://bangordailynews.com/2021/02/06/business/maine-solar-projects-upended-after-cmp-calls-for-more-system-upgrades/

Maine's prior governor was decidedly antisolar. The new governor and legislature passed some solar positive rules and multiple solar farms are being planned and built. The major utility in Maine is already vilified for a disastrous billing upgrade and forcing a new powerline from Canada to Massachusetts through Maine which is still being litigated. There are attempts to pass legislation for the state to take over the utility. This is just going to add fuel to the fire. The process used for system impact studies is intended to keep surprises like this from happening.

[Ampster]

Similar issues in Hawaii and soon in California. Distributed generation requires upgrades at substations. The transformers can handle bidirectional flow but the control systems need upgrading.

[peakbagger]

I have experience with interconnect applications in another state. The utility usually errs on the conservative side. They rarely do the actual studies, they hire third party engineering firms to do actual study and manage the contractors.. If this is multiple projects, it points to management issue of the studies.

Years ago when industrial wind was starting to want access to the grid, the farms tended to be out on the fringes of the grid where power quality was an issue. The utilities were pushing back on the installs until the wind companies proved that they actually could improve power quality. I think most utilities are requiring deploying UL 1741 SA inverters these day at solar farms, they are intended to be used to improve power quality not degrade it.

[Ampster]

......... I think most utilities are requiring deploying UL 1741 SA inverters these day at solar farms, they are intended to be used to improve power quality not degrade it.

I agree It is a step in the direction of a smarter grid. In California the use of frequency to curtail solar would be the perrogative of CAISO, the sytem operator not the power generators.
I still think substation improvements in control systems would add to resiliency of the distribution network.

[khanh dam]

SUNNYBOY5678-DUS111929.indd (sma-america.com)

1741 inverters have been around since 2008, perhaps before then as the above spec sheet shows.
Rule 21 is the newer one that forces people to use newer inverters.