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Energy and EnviroFiciency
A
utomation technology from
Beckhoff
has successfully proven
itself in use worldwide in wind turbines up to a size of 5 MW. PC-
based automation technology offers powerful controllers that unite all
components of a wind turbine - such as operational management and
control of pitch, generator, converter and brake, as well as Condition
Monitoring and farm networking - on a single platform.
Eliminating special hardware lowers the costs of the basic electrical
equipment of the wind turbine and the costs of maintenance, while at
the same time increasing the availability of the wind turbine.The open,
scalable automation software,TwinCAT forms the core of the Beckhoff
PC-based control platform. Open interfaces permit the integration
of third-party software, for SCADA, Condition Monitoring, obstruc-
tion lighting or foundation monitoring, for example. The hardware
interfaces for these functions are integrated into the controller via
standard EtherCATTerminals.
A large variety of interfaces enables the integration of lower-level
fieldbuses such as CANopen, PROFIBUS and EthernetTCP/IP as well
as RS232/RS485. Relocating sub-systems into the field considerably
reduces infrastructure costs and simplifies communication. In com-
parison with conventional IP solutions, wind farm networking with
EtherCAT is faster and offers considerable cost benefits.
The faster the farm networking is, the more effectively the energy
provider can react to voltage drops or changing requirements.With the
EtherCAT Power MeasurementTerminal integrated in the automation
system, momentary current and voltage values can be measured at
up to 10 000 samples/s at the infeed point.
Early diagnosis of voltage drops is thus guaranteed. Unlike alterna-
tive solutions, it is possible to generate a reaction of an entire wind
farm to an LVRT case.Thus, if a voltage drop is diagnosed at the infeed
point, it can be signalled to all turbines in the entire farm within 1
ms. Via the Distributed Clocks in EtherCAT, the measured values of
all wind turbines and the measurement at the infeed point of a farm
can be synchronised to a timeframe smaller than 1 μs.
With these data, the current, voltage and frequency can be control-
led accordingly and the grid can be supported optimally. The exist-
ing fibreoptic-based Ethernet infrastructure can be used. Even the
synchronisation of the IGBTs of converters within a wind farm can
be achieved with this technology.
Enquiries:Tel. 011 795 2898 or email M.Murphy@beckhoff.com.
Efficient control technology for
wind turbines
55
September ‘12
Electricity+Control