The Liebert EXL S1 with Dynamic Grid Support provides static and dynamic frequency regulation by controlling the input power and the batteries charge/discharge based on frequency activation thresholds. It also supports demand management services when the commands to modulate the UPS response are related to demand control flexibility. By enabling UPS grid services with elevated speed of response to frequency variations, data center owners can participate in specific demand/response programs, such as peak shaving. The UPS must be capable of adjusting its power demand on the utility to participate in ancillary services while keeping the critical load backed up with sufficient remaining battery runtime to allow for normal transfer to generators in the event of utility failure. When a grid frequency variation is detected by the external controller, the UPS is commanded to follow this request for both positive and negative regulation by charging or discharging the batteries within their operational limits.
The UPS controls the input power to achieve certain targets or services by working in the following operating modes.