The problem
Some wind turbine technologies connected to electricity networks respond to voltage sags or interruptions in
the network by shutting down automatically in the case of a drop in voltage.
When the increase in the wind power generated in an area exceeds a value with regard to the power from
other forms of generation, these wind turbines are required to continue generating during voltage sags,
following the time/depth pattern represented in the following figure for values established by the electricity
company in each case.
Typical behaviour of the network during short-circuits
Admissible voltage-time curve at the network connection point
Operation of the EOLIC SEPEC
The EOLIC SEPEC is interconnected between the generator and the
network. In normal network regime it behaves like a closed switch.
During the failure, it behaves as follows:
1- With regard to the wind turbine, voltage is supplied as if it
came from the network and the wind turbine is kept in normal
operation.
2- With regard to the network, an active and reactive pattern is
generated in accordance with the needs of the network.
3- During the failure, excess power is dissipated internally by
EOLIC SEPEC
Optionally, SET Q can be equipped to adapt reactive power both during
the gap and in permanent regime.
Table comparing sags adaptation systems
*Spanish standard |