Watt-Var — Model 712

Watt-Var (Model 712) shapes the DER's reactive-power output as a function of its active-power output. Useful for grids where the operator wants the DER to absorb VAR when it's exporting heavily (to limit voltage rise from real-power export) and source VAR when output is low.

The curve is parameterised the same way Volt-Var and Volt-Watt are: a sequence of (W%, Var%) points the DER linearly interpolates between.

The Watt-Var curve and its application over the operating range:

Watt-Var curve definition Watt-Var operating envelope, point 0 Watt-Var operating envelope, point 1 Watt-Var operating envelope, point 2 Watt-Var operating envelope, point 3 Watt-Var operating envelope, point 4

To drive Watt-Var from a script, write the Model 712 curve over Modbus (see SunSpec Modbus Server) or POST to /api/dersim/grid-support (see REST + WebSocket API). When multiple reactive-power modes (Watt-Var, Volt-Var, fixed PF, fixed VAR) are commanded simultaneously, see AC Controls for the precedence rules.