ABB ACS800-67, System Description And Start-Up Manual

Page: 38 / 120

38 System description

Stator contactor (par. 16.20 GRID CONNECT MODE set to
MCB1+MCB3/C)
The configuration below is used when MCB1 and MCB3 are connected in series.
The breaking device type for the grid connection is defined by parameter 20.27 CONT
OPEN CUR.
•
0 A = main circuit breaker or medium voltage circuit breaker MCB3 is used for
disconnecting stator from grid
•
> 0 A = contactor MCB3 is used for disconnecting stator from grid.
When parameter value [> 0 A] is selected, the converter can be disconnected from the grid
in two ways depending on a parameter setting:
•
If measured current 06.29 STATOR IS NO FILT is below the parameter value, the
converter uses the stator contactor only.
•
If measured current 06.29 STATOR IS NO FILT is above the parameter value, the
converter first opens the breaker and, after a short time, the stator contactor.
The parameter value is compared to unfiltered stator rms value. Since the unfiltered value
always contains a certain amount of noise, it is recommended to set the parameter to a
value of contactor nominal c15%. See the delivery specific circuit diagrams.

Settings
Parameter 20.27 CONT OPEN CUR.
In case of one contactor, the value for parameter 20.27 CONT OPEN CUR is the nominal
current of the contactor.
ISU
INU
G
MCB1 MCB3
MCB2
Turbine
transformer
MCB1 stator breaker
MCB2 converter contactor
MCB3 stator contactor