ABSTRACT:
Due to significantly higher
and more constant wind speeds and the shortage of suitable sites for wind
turbines on the land, offshore wind farms are becoming very attractive. The
connection of the large offshore wind farms is possible with HVAC, classical
HVDC and Voltage Source Converter (VSC based) HVDC technology. In this paper
their main features will be given. From the economical and technical viewpoint,
the type of connection depends on the size of the wind farm and on the distance
to the connection point of the system.
As very promising
technology, especially from the technical viewpoint, the focus of this paper
will be put on the VSC-based HVDC technology. Its main technical features as
well as its model will be detailed. At the end, obtained simulation results for
different faults and disturbances for one offshore wind farm connected with
VSC-based HVDC technology will be presented.
KEYWORDS:
2.
IGBT
3.
Offshore wind farm connection
4.
PWM
5.
Requirements
6.
Stability
7.
VSC
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1. Principal scheme of VCS-based HVDC connection
EXPECTED SIMULATION RESULTS:
Fig. 2. Active and reactive power at the connection
point during reactive power control
Fig. 3. Active and reactive power at the wind farm
side during reactive power control
Fig. 4. Active power, reactive power and voltage at
system and wind farm side in case of single phase short circuit near to the
connection point - 100ms
Fig. 5. Active power, reactive power and voltage at
system and wind farm side in case of single phase short circuit at the wind
farm side - 100ms
CONCLUSION:
The
connection of an offshore wind farm depends primarily on the amount of power
that has to be transmitted and the distance to the connection point.
Primarily
due to comparatively small size and short distance to the connection point as
well as due to its lower costs and experience, all actual offshore wind farms
and those planned to be installed are still using/plan to use HVAC connection.
The
advantages of using a HVDC solution are more significant with increase of the
distance and power.
The
VSC-based HVDC technology is due to its technical advantages like: active and,
especially, reactive power control (voltage control), isolated operation, no
need for an active commutation voltage etc. very good solution for an offshore
wind farm connection. Performed simulation and their results of simulated
faults and disturbances show that the technical requirements can be fulfilled.
REFERENCES:
[1] European Wind Energy Association. (2004). Wind
Energy – The Facts. [Online]. Available: http://www.ewea.org
[2] Global Wind Energy Council. (2004). [Online].
Available: http://www.gwec.net
[3] F.W. Koch, I. Erlich, F. Shewarega, and U.
Bachmann, "Dynamic interaction of large offshore wind farms with the
electric power system", in Proc. 2003 IEEE Power Tech Conf., Bologna,
Italy, vol. 3, pp. 632-638.
[4] J.G. Slootweg and W.L. Kling, "Is the Answer
Blowing in the Wind?", IEEE Power and Energy Magazine, vol. 1, pp.
26-33, Nov./Dec. 2003.
[5] Wind Energy Study 2004. [Online]. Available:
http://www.ewea.org
