Offshore Wind Park Connection To an HVDC Platform Without Using an AC Collector Platform

Offshore Wind Park Connection

This thesis investigates the comparison between two different alternating current topologies of an offshore wind farms connection to an offshore high voltage direct current (HVDC) converter platform.

The offshore high voltage direct current converter platform converts alternating current into direct current. Two different topologies will be investigated.

In the first topology, the offshore wind farms are connected to an HVDC converter platform through offshore AC collector platform.

In the second topology, the offshore AC collector platform is removed from the circuit and the offshore wind farms are connected directly to offshore HVDC converter platform.

In this thesis, short circuit analysis and loss analysis of an offshore wind farm cluster connected to an offshore HVDC converter platform is conducted for the two topologies described above.

Two internal voltage levels i.e. 33 kV and 66kV of wind farms are compared for short circuit currents in the absence of AC collector platform.

DIgSILENT software is used to perform short circuit calculations.

The thesis is done in collaboration with “Offshore Wind Connections” department ABB, Sweden. The idea is still under development however this study will serve as good starting point to figure out the cost efficient AC topology of an offshore wind park HVDC connection.

Thesis Structure

Following is the structure of the thesis:

Chapter 1 – Introduction (this section) describes the methodology and scope of this thesis and gives an overview of the structure

Chapter 2 – Internal Electrical Layout Comparison of an Offshore Wind Farm discusses the two options for internal wind farm connections and gives cost and loss analysis.

Chapter 3 – Components of an Offshore HVDC Link discusses the importance of the components present in an offshore HVDC link and their cost trends.

Chapter 4 – Cost Estimation discusses the costs of different components in the AC collector platform and HVDC converter platform.

Chapter 5 – Short Circuit Analysis of an Offshore Wind Farm discusses types of wind turbine generators currently used in the industry and their short circuit contributions.

Chapter 6 – Offshore Wind Farms Connection Using DIgSILENT analyses two different cases of wind farm cluster connection to an offshore HVDC converter platform for short circuit current calculation.

Chapter 7 – Loss Analysis discusses the loss analysis of two cases of wind farm cluster connection to an offshore HVDC converter platform.

Chapter 8 – Conclusion presents the overall conclusion obtained from this study and future work that can be done in this field.

The span of this thesis is twelve weeks (26th March, 2012 to 17th June, 2012) which is scheduled in such a way that half of the time is dedicated for the literature review and half for the execution of calculation and analysis.