Research On Uncertainty Risk Assessment Of The Wind Power Generation System

Development and security are contradictory.With the rapid rise of wind power industry,there is inevitable impact on the stability of power system,such as frequent WTG off-grid accident,fire accidents,tower falling accidents,blade accidents,etc.resulting in personal injuries and property damages which can not be ignored.How to reduce the risk to an acceptable state by some control methods and means to achieve safe,stable and orderly development of wind power has become an urgent problem to be solved.Wind power generation is a complicated system.In addition,there are a lot of potential uncertainty risks in wind power generation system due to the relatively remote location of wind power project,lack of spare parts and operation and maintenance personnel as well as lack of management experience.Thus,large amount of potential uncertainty is embedded in wind turbine generation system.Based on previous research,it is found that it is necessary for the development of research on contemporary technology safety to find deficiency,comprehensively use various theories and methods combined with the characteristics of wind power generation,study the control method for uncertainty risk of wind power system and build theoretical system to eliminate and curb the occurrence of accidents.In order to realize the safe and stable operation of wind power generation system,this paper introduces the system theory,risk management theory,uncertainty management theory and method.The research is conducted from theoretical system construction for uncertainty risk of wind power system,risk assessment and risk control and its main research work and innovation are reflected in the following aspects:(1)In this paper the relationship between risk and uncertainty,qualitative risk and uncertainty risk is discussed,and then the definition of uncertainty risk is put forward.Based on the theoretical framework of uncertainty system and combined with various theories,theoretical framework of wind power generation system science,theoretical framework of wind power generation system risk management and that of wind power generation system uncertainty are established,and finally the theoretical framework for uncertainty risk assessment of wind power generation system is formed.(2)In this paper,hierarchical model,aggregation model and relational model of wind power generation complex system are established,and the concept of related network line is put forward,which provides the theoretical support for unit division and system construction of risk assessment on wind power generation system.The failure type influence analysis method is combined with the pre-hazard analysis method.The pre-failure type influence analysis method is proposed and applied to risk analysis and evaluation of wind power system accidents.The application shows that this method can find out the root cause and possible inducement of the hidden trouble,which is helpful for the technical personnel to fully understand the hidden dangers of wind power generation system and provide technical support for risk control in the future.(3)Using Markov principle,the frequency and duration of wind turbines based on Markov process are defined.The series equivalent method is applied to the reliability calculation of wind turbines and the generalized Markov process is constructed by adding the variable method in the reliability calculation process of delay repair system.Based on the principle of Markov process,the Markov reliability model of wind turbine is established and its reliability risk assessment is carried out to verify the correctness and practicability of the model.(4)The association degree is redefined and the improvement study of set pair potential is conducted.The generalized set pair potential is established,and the application range of set pair analysis is extended.And the weight interval of each evaluation index is determined by using the uncertainty method and taking expert weight into consideration.The weight interval is transformed by the expression of the connection number,and a comprehensive calculation method of hierarchical-interval-set pair method is proposed,which integrates the interval mathematics,the hierarchy analysis method and the set pair analysis method.This weighting method is applied to set pair analysis risk assessment of the set-to-loop wind power generation system.The application shows that the uncertainty of wind power generation system is effectively treated by the set pair analysis method,which emphasizes the relativity and fuzziness of information processing,thus,the accuracy of the evaluation is improved.(5)Combining the catastrophe theory with the fuzzy theory,changing the certain numbers of the original evaluation index into fuzzy numbers,this paper proposes a mutation fuzzy evaluation method,which makes the uncertainty information be applied more broadly.The human-machine-environment risk assessment index system and the hierarchical catastrophe model are established,and the fuzzy dynamic evaluation of wind power generation system based on catastrophe theory is carried out,and the gap between evaluation conclusions is widened through the improvement study of the change method.Through the comparison and analysis of the results obtained by the traditional mutation assessment method,the catastrophic fuzzy method can more accurately assess the safety production status of the wind power generation system.(6)The expert weighting method and the entropy method are combined to determine the weights.The assignment problem is extended to the problem rectification interval of wind power generation system by applying a multi-objective assignment method based on interval number optimization model.The application shows that the method takes full account of the relationship between the time of rectification and safety capital investment and the safety benefit,and makes the total efficiency and total cost of the task achieve anticipated goals.(7)The advantage of using simplicity theory to deal with uncertain knowledge is put forward,and the evaluation index of emergency rescue capacity of wind power generation system is simplified.A matter element analysis model of emergency rescue capability of wind power generation system is established.Wind power emergency rescue capability evaluation system software is developed based on rough set matter element analysis.The application shows that the evaluation method proposed and the evaluation system developed are easy to use and have good prospects for future application.