Behaviour and Protection of doubly-fed induction generators during network faults
作者:
Sarah Foster, Student Member, IEEE, Lie Xu, Senior Member, IEEE and Brendan Fox
所属专业方向:
wind power
摘要:
The paper considers the behaviour of the rotor current of
a DFIG during a fault on the network. It is seen that a large
disturbance of the stator voltage will cause high transient rotor
currents which trigger the crowbar protection for the rotor side
converter (RSC). Once the crowbar is applied it cannot be removed
until its current reaches zero. During the period the crowbar is
applied, the machine behaves as a conventional FSIG, losing control
of the active and reactive power. Therefore the time taken for the
crowbar current to reach zero is crucial as it determines when the
RSC can regain power control and how soon the AC voltage can
recover. It is seen that the crowbar current can take a long time to
decrease to zero and that this has a significant impact on the voltage
recovery after fault. The larger the crowbar resistor and the further
the generator is from synchronous speed, the shorter the crowbar
current transient is. Power and energy dissipation through the
crowbar resistor are also considered, and it is observed that the
power varies in accordance with the maximum power transfer
theorem. The detailed impact of the timings of crowbar removal and
RSC reactivation on system voltage recovery is also investigated. It is
seen that reactive power control during fault clearance can assist AC
voltage recovery.
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发表于 2009-7-29 02:40:28
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