10
Specifications
10.1
Reactive power control
Reactive power can be used in electrical energy supply networks to bolster the level of voltage. As such, feed-in
inverters can contribute to statistical voltage stability. Reactive power brings about a voltage drop at the in-
ductive and capacitive components of the equipment which can either bolster or reduce the level of voltage. If
the generating plant draws inductive reactive power while active power is being fed in, part of the voltage
swing caused by the active power feed can be compensated for by the supply of reactive power.
This reactive power mode and the respective control process are specified by the grid operator. If no control
process has been specified, then the system should be operated using a reactive power specification of 0%.
10.1.1 Dynamics and accuracy
n all of the control methods described below the specified set value at the inverter’s connection terminals is
adjusted using a stationary deviation of the reactive power of maximum 2 % QN. This maximum deviation al-
ways relates to the specified value as reactive power.
If the power factor cos ϕ is specified in the control method, then the deviation relates to the reactive power
value brought about by the current power.
The transient response of the control methods are determined by a PT-1 filter. The settling time corresponds to
5 Tau, or in other words, achieving approx. 99 % of the final value of the PT-1 filter. Subject to the control
method selected, there are also other parameters that determine dynamic behaviour as described below.
10.1.2 Reactive power functions
The following functions for controlling the reactive power are implemented in the devices listed above:
– cos ϕ constant
– Q constant
– cos ϕ /(p/pn)
– Q(U) 10 nodes
NOTE: Reactive power is prioritised in each method. The maximum possible active power that
can be fed in is reduced in line with the P-Q operating range when a specific reactive power
level is specified.
cos-φ constant
In cos-φ-constant mode, the specified power factor is fixed by the inverter. In doing so, the reactive power
level is set in line with Q=P*tan ϕ as a function of the power that continuously generates the specified power
factor. If the set value is changed, the new value is taken over damped by a filter. The settling time can be para-
meterised and is 1s (this corresponds to 5 tau. (The VDE templates usually specify 3 Tau)) with the transient re-
sponse of a first-order filter (PT-1) with a time constant of Tau=200ms. The specified power factor can be con-
figured on the display or by way of communication via the KACO RS485 protocol and MODBUS/SunSpec.
If the applicable grid code stipulates that the cos-ϕ should react to the target value slower than the configured
Tau=200 ms by way of a defined gradient or settling time, this gradient or settling time must be implemented
in the system control.
Parameters
Setting
Refer-
ence
Description
cos-phi const.
[OutPFSet_Ena]
1-0,3 [°]
Set the power factor to a certain % value.
Power gradient increasing
& power gradient decreas-
ing
[OutPFSet_RmpTms]
1 – 65524 [% Slim / min]
Specifies the dynamic behaviour when
changing the power factor cos ϕ. The
power factor is changed with the set gradi-
ent.
Note: The gradient is overlaid with the set-
tling time.
10 | Specifications
Manual
KACO blueplanet 100 TL3
Page 72
EN
