10.4.3 Normal operation power gradient
In the case of very large plants, it may also be necessary to restrict the change in power level during normal op-
eration. If the set value (for increase and decrease in power level) and the solar irradiation change (for increase
in power level), then the grid feed-in power is increased or decreased in line with the configured gradient. A
limitation is not possible if the solar irradiation is reduced.
This function isn’t active for changes in the power, which are defined by another grid support action such as
the return of power after Fault Ride Through, P(f), P(U).
10.4.3.1 Normal operation power gradient
Country-
spec. Set-
tings
Men
u
level
Display/
Setting
Action in this menu/meaning
Operation Mode
On / Off
Activate or disable the power gradient limtitation in normal operation.
Increasing gradient
1-65534 [% S
max
/
min]
The change in the active power is limited to a configured power increase
gradient.
Decreasing gradient
1 – 65534 [% S
max
/
min]
The change in the active power is limited to a configured power de-
crease gradient.
10.5
Advanced islanding detection
Due to decentralized generation, there is the possibility that a deactivated part of the grid will remain live in an
unintended island due to the balance of load and generation in this part of the grid. The detection of unin-
tended island formation is an important function of decentralized generating units and is related to the preven-
tion of damage to equipment as well as safety of personnel.
Depending on the structure and the operation of the distribution grid several dangers exist:
– In case of maintenance work in a distribution grid, personnel may be placed in danger if the deactivated
part of the grid remains live as an island. This is especially the case if not all safety rules are followed.
– If fast auto-reclosure is used in a distribution grid and the deactivated part of the grid remains live as an is-
land, reclosure will likely happen during phase displacement which might cause damage to rotating ma-
chinery on the grid.
– In the event of a fault in a medium voltage grid, the faulty part of the grid is disconnected. If the fault has a
significant resistance, the deactivated part of a medium-voltage grid remains live as an island. Depending
on the type of fault, but explicitly in case of a fault in the transformer, dangerous medium voltage might be
accessible or even present in low-voltage appliances.
Especially for the last example very fast disconnection of the generating units to cause collapse of the forming
island is necessary. At the same time any island formation detection method may cause false tripping. The in-
dustry is therefore in constant research to develop methods that are fast and reliable and at the same time reli-
ably prevent false tripping.
Enhanced island detection method
KACO new energy's advanced islanding detection, uses a strategy to reliably detect islanding formation that is
based on the characteristic differences between an interconnected grid and an islanded grid, thus ensuring reli-
able fast detection and prevention of false tripping.
An interconnected grid is dominated by rotating machinery, as a consequence frequency is proportional to ac-
tive power balance and voltage is proportional to reactive power balance. In contrast an islanded grid behaves
like a resonant circuit, as a consequence frequency is proportional to reactive power balance and voltage is
proportional to active power balance. The active enhanced island detection method detects this difference by
monitoring the behaviour of the grid. The enhanced island detection is monitoring the natural fluctuation of
the grid frequency and injects a minimal reactive power proportional to the rate of change of frequency. In the
10 | Specifications
Manual
KACO blueplanet 110 TL3 KACO blueplanet 125 TL3
Page 94
EN-US
