| Abstract |
This paper considers the technical challenges inherent in establishing an HVDC converter
station on an off-shore platform and bringing the power ashore via submarine cables. The
harsh environmental conditions and the inaccessibility during certain times of the year add to
the technical issues involved in integrating the HVDC converters into the wind farm
installation. The paper describes the choice of topology used for the Voltage Source
Converter (VSC), which is based on the multi-level (or chain link) design of circuit. This
topology has advantages over PWM based control of 2-level or 3-level converters, which will
be discussed in the paper. A key issue for inter-connections to off-shore wind farms is the
strength of the on-shore grid and its ability to receive the power flows. The benefits that VSC
technology brings to this aspect of grid connection will be described.
The off-shore HVDC converter station will be installed on a dedicated platform, which is
connected to the AC collector platform for the turbine array, by a HVAC cable, typically 132 –
150kV. The design of the HVDC platform needs to incorporate a high voltage converter
valve hall, which requires a high degree of protection from the harsh environment. The
converter transformer, either three-phase or single- phase units, needs to be accommodated
on the platform, plus spare units as required. To minimize space requirements, Gas
Insulated Switchgear is used for the AC connections. The paper discusses the design of the
platform layout to achieve the most compact design to minimize the size, weight and cost of
the structure. Installation of the HVDC equipment on the platform and the installation of the
platform at its off-shore location represent significant technical challenges and these are
described in the paper. |
