Wind power has become the most successful renewable energy and represents the second-largest power generation capacity (175 GW) in Europe after natural gas [1]. At the end of 2019, there was an installed accumulative wind power capacity in the UK of 23,513 MW of wind power generating more than 50 TWh of energy [2].
One of the main drivers in wind technology is the reduction of the project cost (CAPEX) and the operation of maintenance cost (O&M). The wind turbine collection system is gaining attention as a potential cost saver infrastructure. Different alternatives have been suggested: DC parallel connection [3], DC series connection [4] and low AC frequency collection systems [5]. Some researchers have suggested that DC collection systems for wind farms might present reduced running cost compared to the standard AC technology, but it is highly dependent on the used DC converter technology [6,7].
This PhD proposal aims to investigate a new integrated DC collection system that might improve the wind farm efficiency and reduce the wind farm construction and operational cost. A potential solution, the AC collection system is replaced by a DC system where the AC network is interfaced by a multilevel converter ensuring low harmonics emissions and grid compliance in any scenario. This PhD seeks to use the existing generator and generator converter technology based on a permanent magnet synchronous machine and two-level voltage source converter. Apart from the wind turbines, different elements like photovoltaic generation systems and energy storage elements can be added to the collector system enabling the provision of ancillary services such as inertia emulation [8] and frequency support, without disturbing the turbine operation. This scheme is in the early development stages and requires further research regarding the wind turbine and converter topologies, control, protection and stability perspective.
Aims and Objectives
The goals of this PhD proposal can be summarised as:
1) Identify, evaluate and compare different wind farm collection systems including DC and low-frequency AC minimising the CAPEX and OPEX and maximise the efficiency, reliability and availability.
2) A detailed study of one or more of the selected topologies including modelling, control, performance evaluation, stability analysis and safety protection concept. A small lab setup is expected