Power Control System Flavors

SolarAPP+ supports equipment that has been listed to UL 1741 PCS CRD or UL 3141, the standard for Power Control Systems. The product safety standard allows for equipment to be listed for Power Export Limiting at the Point of Common Coupling.

Busbar Control - A system that relies on external current sensors to monitor the flow of current across a busbar. Software curtails the output of renewable sources when the ampacity of the busbar is reached. A busbar is capable of supporting current flow up to 80% of its maximum rating for continuous duty loads and sources. PCS ampacity settings should be set at 80% of the OCPD rating protecting the busbar.

Power Export Limiting (aka ESS Discharge Limiting) - A configuration that limits the total renewable energy output of a system. Additional overcurrent protective devices are required to handle overload conditions. For SolarAPP+, this means that the rating of the OCPD protecting the backup initiation device (BID) x 0.8 (continuous duty factor) must comply with the 120% rule at the connected busbar. For the system detailed below, the output of the 11.5kW inverter has been limited to 32A.