Research On Power Cable Optimization And Life Cycle Cost Management Of Offshore Wind Farm

In the situation of global resource and environmental problems increasingly serious,developing wind power and other renewable energy vigorously has become an important means to protect the ecological environment and ensure energy security.At the same time,it has become a trend that the offshore wind farms are being developed vigorously.Power cables are seen as an important part of offshore wind farms.In order to reduce production costs and improve the utilization of wind resources,it is necessary to optimize the collector system which affects the operation security and economization of the whole wind farm,integrate the uncertainty of the environmental factors into the optimization of the delivery line system,and coordinate the entire wind farm stage costs from the perspective of the whole life cycle.The main research work of this dissertation is listed as follows:Firstly,the sum of investment costs about submarine medium voltage cables,switch equipment and others,operation and maintenance costs as well as failure costs are regarded as the optimization goal directing at typical radial and ring topology for collector system in this dissertation,which aims to establish an optimization model that takes into account both economy and reliability.Then constraints are built combining with the actual operating conditions of submarine cables.And the improved genetic intelligence algorithm is used to solve the optimization model of collector system.The validity of the proposed scheme is verified through the case simulation analysis.Secondly,a method of selecting the submarine cable based on the semi-invariant method and Gram-Charlier series theory is introduced,which considers the random output of the wind farm and the ambient temperature.Stochastic models of wind power generation and ambient temperature are established,and they are imported to the thermal circuit model of submarine cable to calculate the conductor core temperature under the worst case combination condition.Next,the probability distribution curve of the core temperature can be obtained,thereby,the optimized submarine cable can be chosen.Besides,the finite element transient analysis method is also applied to select the best cable,which verifies the feasibility of semi-invariant method,and ultimately the economic and stable submarine cable can be obtained.Additionally,the COMSOL commercial software can be discarded in the actual project in order to reduce engineering design costs.Thirdly,the cost of the offshore wind farm construction project is divided stage by stage,which includes initial investment cost,operation and maintenance costs,fault penalty costs and scrap costs,thus the life cycle cost(LCC)mathematical model of wind farm is established.Thereinto,wind resource probability statistics are considered when calculating the cost of electromechanical equipment energy consumption in operation and maintenance process,which means to establish a mathematical cost model that is aligned with the actual situation of wind farm.Furthermore,the Monte Carlo simulation method is used to calculate the failure penalty cost.Finally,the offshore wind farm life cycle economic evaluation software is developed based on the life cycle cost mathematical model.The design principles and development process of the software are illustrated in this section.What's more,the design methods and operational processes of the initial investment cost,operation and maintenance costs,fault penalty costs,scrap costs and the life cycle cost are demonstrated fully.Finally,the reliability and practicality of the software are be verified through the case analysis.The research work in this paper has improved the shortcomings of subjectivity and irrationality about the traditional topology layout and the selection of the delivery line.In addition,the mathematical model of life cycle cost of offshore wind farm provides theoretical reference for engineering personnel,and the software being developed provides technical support for scientific and intuitive assessment about economic benefits of the wind farm project life cycle process.