Dynamics And Accuracy; Reactive Power Functions - Kaco blueplanet 29.0TL3 Serie Manual

Manual

10.1.2 Dynamics and accuracy

In all control methods the specified target value at the inverter's connection terminals is adjusted using
a stationary deviation of the reactive power of maximum 2% S
tes to the specified value as reactive power. If the shift factor cos ϕ is specified in the control method,
then the deviation relates to the reactive power value brought about by the current power level.
The transient response of the control methods is determined by a PT-1 filter. In this case, the settling
time corresponds to 5 Tau, or in other words, achieving approx. 99% of the final value for a PT-1 filter.
Subject to the control method selected, there are also other parameters that determine dynamic beha-
viour.

10.1.3 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
– 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 displacement factor cos-φ is set permanently by the inverter. In
doing so, the reactive power level is set according Q=P*tan φ dependent on power output which pro-
duces the specified displacement factor cos-φ continuously. If the specification is changed, the new
value is adopted attenuated by a filter. The transient time is 1 s with the transient response of a first-
order filter (PT-1) with a time constant of Tau=200ms. The specified displacement factor may be confi-
gured in the display or via communication, via KACO RS485 protocol and MODBUS/SunSpec.
If the applicable grid code requires the cos-φ response to set point by a defined gradient or settling ti-
me slower than the configured Tau=200ms, this gradient or settling time must be implemented in the
plant control system.
Q constant
In Q constant mode, the specified reactive power value is set permanently by the inverter. If the speci-
fication is changed, the new value is adopted attenuated by a filter. The transient time is 1s with the
transient response of a first-order filter (PT-1) with a time constant of Tau=200ms. The specified reac-
tive power may be configured in the display or via communication, via KACO RS485 protocol and
MODBUS/SunSpec.
cos ϕ /(P/Pn)
In cos ϕ/(P/Pn), mode, the set value of cos-φ and, derived from this, the set value of the reactive po-
wer is calculated continuously as a function of the actual power level. This function ensures that grid
support is provided by the reactive power when a significant voltage increase is anticipated due to a
high feed.in level. A characteristic curve is specified which can be used to configure up to 10 nodes,
value pairs for active power and cos ϕ. The active is entered as a % in relation to the nominal power.
Other parameters allow to limit functionality and to limit activation to certain voltage range.
Fig. 47: cos φ / (P/Pn) standard characteristic curve with 3 nodes
Kaco blueplanet 29.0TL3
Specifications | 10
. This maximum deviation always rela-
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