
Title: Smoothing wind farm output power through co-ordinated control and short term wind speed prediction
Author: Clemow, Philip R.
ISNI:       0000 0004 2714 8566
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2012
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In recent years the energy sector has looked to renewables as a means to reduce emissions. Wind power is able to provide large amounts of energy at a reasonable cost from presently available products. Thus the amount of wind generation has risen steeply in recent years, notably in the countries of northern Europe. However, this rise in wind power has lead to issues regarding the variability of the wind power output. Wind power is related to the wind speed, which varies greatly. This variability can cause issues with wind operators' ability to participate in electricity markets and can also lead to a rise in balancing costs. The system proposed in this thesis aims to reduce the variation of wind farm output seen in the minute to minute time-scale and provide controllability in longer time-scales. To do this the system uses short-term wind speed predictions and the inertial energy storage of the wind turbines themselves and does so in a co-ordinated fashion across the whole farm. Using short term wind speed predictions, the amount of energy in the wind is calculated for the next short period. This energy can be exported in a controlled manner using the inertial energy to cover short-term wind energy shortfall or excess. The rotor speed must vary for the storage effect to be achieved and this requires extra control systems to prevent over-speed or turbine stalling. The system was tested and found to be effective at smoothing the output power in a range of different wind scenarios. Tests were performed to assess the effects of using co-ordinated control on the frequency of an example grid and on the use patterns of portfolio generators. Both tests show that the use of a co-ordination controller at wind farm level reduces the balancing burden on the remainder of the system in comparison with the common maximum power form of control.
Supervisor: Green, Tim Sponsor: EPSRC
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral