Reactive power control with voltage characteristic curve Q(U)
Setting eReactiveMode = ByVoltage
activates the voltage characteristic curve Q(U) for reactive power control. The parameters of the ReactiveByVoltage
group are used to configure the voltage-dependent characteristic curve Q(U) (see ReactiveByVoltage).
A lookup characteristic curve ReactiveByVoltagePoints
is prepared as a parameter with 4 operating points. The operating points are preset according to VDE-AR-N 4110. A vertical offset of the characteristic curve can be specified with the ReactiveByVoltageOffset
parameter and shifts the voltage for Q=0
. A voltage deadband can be set with ReactiveByVoltageDeadband
parameter.
As soon as the voltage exceeds the limits of the deadband, a new reactive power setpoint is calculated and approached. This results from the intersection of the measured voltage and the exceeded deadband limit. The implemented characteristic curve with the parameters used is shown in the following figure. The EN standards require a blocking and unblocking power as well as a minimum CosPhi to limit the reactive power at low active power levels.
These requirements are provided by the controller via the additional parameters ReactiveByVoltageStrPower
, ReactiveByVoltageStpPower
and ReactiveByVoltageCosPhiMin
and must be disabled for VDE standards.
