On the optimisation of operation and maintenance strategies for offshore wind farms

摘要

This thesis reports on investigations undertaken into the reliability, availability andudmaintenance of offshore wind farms when considering different maintenance strategies,udan understanding of which is fundamental when considering the technical andudeconomical viability of existing and future offshore wind farms.udA comprehensive literature review has been undertaken in the areas of offshore windudfarm maintenance strategies, offshore wind turbine reliability and accessibility issues,udand CO2 emissions associated with maintenance expeditions for offshore wind farms.udThe limitations and disadvantages of current maintenance practices are identified and audplanned intervention maintenance policy is proposed and examined in detail.udTo help design a planned intervention maintenance policy, the offshore wind farmudparameters that affect its technical and economical viability have been identified, whichudbecome the foundation for developing computer based models using Monte Carloudsimulations to quantify the maintenance practices of the planned interventionudmaintenance policy. Different scenarios of the proposed solution are investigated to helpudquantify the technical and economical benefits over the current maintenance practises,udin terms of wind farm availability, cumulative energy output, production cost of energyudand CO2 emissions.udThe research on the reliability of offshore wind turbines has shown that the powerudconverter system is a critical item that suffers from high failure rates. This thesis reportsudupon the investigation of a hot standby redundancy on the wind turbine power converterudsystem. A redundancy model is deployed to simulate the planned interventionudmaintenance policy for different offshore wind farm case studies in order to establishudthe effects of the hot standby redundancy on the offshore wind turbine operationaludperformance.udThe novel contribution of this work is claimed to be in the development of dedicatedudmodels for the reliability, availability and maintenance of offshore wind farms, whichudshould lead in establishing a technical and economic benchmark for the parametersudaffecting offshore wind farms.