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

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20 System description
Wind turbine system operating speed area
The example below illustrates the generator speed control in different wind speed ranges.
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
0
0 300 600 900 1200 1500 1800 2100 2400 2700
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
0
3000
n
min
n
max
n
1
n
A
n
3
n
r
n
2
n
B
n
sync
W
ind
turbi
ne
po
wer (kW
)
In operating range n
1
… n
3
the rotational speed is under normal operating conditions.
Generator rotational speeds:
n
min
minimum rotor speed which may never be reached, not even momentarily 1)
n
max
maximum rotor speed which may never be exceeded, not even momentarily 1)
n
1
minimum rotor speed when the converter is tripped due to underspeed (30.10 UNDERSPEED LIMIT
level) ie, torque will be controlled to zero and all breaker(s)/contactor(s) are opened 2)
n
2
rotational rotor speed deviation upwards or downwards with nominal power production within standard
tolerance
n
3
maximum speed when the converter is tripped due to overspeed (30.09 OVERSPEED LIMIT level) ie,
torque will be controlled to zero and all breaker(s)/contactor(s) are opened 2)
n
A
cut-in speed equals to the converter minimum operating speed while converter starts and generator
stator synchronisation is allowed (20.21 SWITCH ON SPEED and 20.22 SWITCH OFF SPEED
levels)
n
B
cut-out speed ie, the speed at which the turbine control system must immediately shut down the wind
turbine
n
r
rated speed ie, rotational speed at rated wind speed to generate nominal power to electrical power
network
n
sync
generator synchronous speed
1) Activation speed ie, the rotational speed at which the turbine safety system must be triggered immediately
(wind turbine and pitch level protection)
2) If the speed is below (
n
1
) or outside ( n
3
) the speed area, the converter may be damaged due to high rotor
voltage during the shutdown procedure. Generator stator synchronisation to electrical power network is not
allowed in any circumstances and grid disconnection is always required.
=
=
=
=
=
=
=
=
=
U
max
Converter
operation is not
allowed
Rotor voltage
(V)
U
cont.max
Rotor speed (rpm)
Converter
operation is not
allowed