If you are connecting a solar PV system above 30kW to the grid you will be required to install an extra level of protection including-
Under Over Frequency
The unit is designed to fully comply with Utilities’ connection requirements and statutory codes, offering a high level of protection and safety when working in parallel to the mains.
ANSI Protection Codes
27, 59, 81H, 81L, 78, 81R, 47