PUC Relays for a 500KW System

[NorthwestPV]

We are installing a 500KW system at a factory. The power company said they "SOMETIMES" require relays for systems over 300KW. I asked if they have documentation that explains their requirement. NOPE. I asked him what's the purpose of the relays? He said, if we are required to install them, based on their review of our system and grounding, it's to protect the neighbors. Have any of you been required to do this? We would like to calculate the cost into the estimate in the event that the power company requires it.

 

[SolarPro]

The high end of the cost spectrum is probably something like this:

https://www.selinc.com/SEL-351/

I know these are used in some large industrial/utility-scale PV interconnections, as required by the utility. Eaton even had a Schweitzer protection system integrated into the switchgear they had on display in Orlando for SPI 2012.