Analysis of reactive power strategies in HVDC-connected wind power plant clusters

© 2017 John Wiley & Sons, Ltd. Offshore wind power plants (WPPs) built near each other but far from shore usually connect to the main grid by a common high-voltage DC (HVDC) transmission system. In the resulting decoupled offshore grid, the wind turbine converters and the high-voltage DC voltage...

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Bibliographic Details
Authors: Schönleber, Kevin, Ratés Palau, Sergi, Gomis Bellmunt, Oriol|||0000-0002-9507-8278
Format: article
Publication Date:2017
Country:España
Institution:Universitat Politècnica de Catalunya (UPC)
Repository:UPCommons. Portal del coneixement obert de la UPC
Language:English
OAI Identifier:oai:upcommons.upc.edu:2117/112798
Online Access:https://hdl.handle.net/2117/112798
https://dx.doi.org/10.1002/we.2134
Access Level:Open access
Keyword:Wind power
Electric driving
Electric power transmission
Wind power plants
Grid integration
HVDC transmission
Load flow
Power system management
Reactive power
Voltage control
Energia eòlica
Control elèctric
Energia elèctrica--Transmissió
Parcs eòlics
Àrees temàtiques de la UPC::Energies::Energia eòlica
Àrees temàtiques de la UPC::Energies::Tecnologia energètica
Description
Summary:© 2017 John Wiley & Sons, Ltd. Offshore wind power plants (WPPs) built near each other but far from shore usually connect to the main grid by a common high-voltage DC (HVDC) transmission system. In the resulting decoupled offshore grid, the wind turbine converters and the high-voltage DC voltage-source converter share the ability to inject or absorb reactive power. The overall reactive power control dispatch influences the power flows in the grid and hence the associated power losses. This paper evaluates the respective power losses in HVDC-connected WPP clusters when applying 5 different reactive power control strategies. The case study is made for a 1.2-GW-rated cluster comprising 3 WPP and is implemented in a combined load flow and converter loss model. A large set of feasible operating points for the system is analyzed for each strategy. The results show that a selection of simulations with equal wind speeds is sufficient for the annual energy production comparison. It is found that the continuous operation of the WPPs with unity power factor has a superior performance with low communication requirements compared with the other conventional strategies. The optimization-based strategy, which is developed in this article, allows a further reduction of losses mainly because of the higher offshore grid voltage level imposed by the high-voltage DC voltage-source converter. Reactive power control in HVDC-connected WPP clusters change significantly the overall power losses of the system, which depend rather on the total sum of the injected active power than on the variance of wind speeds inside the cluster.