Research On Key Technologies Of Large Scale Wind Power Participation In Power System Restoration

With the increasing attention paid by the international community to energy security,ecological environment protection and climate change,accelerating the development and utilization of renewable energy has become a common consensus and concerted action of most countries in the world.The installed capacity of global wind power increased from 120.7 GW in 2008 to 590.9 GW in 2018.Large-scale wind power integration brings greater uncertainty to power system operation and increases the risk of blackouts.However,the characteristics of small starting power and fast starting speed of wind power can make it play an active role in power system restoration.Therefore,it is of great significance to study how to make large-scale wind power safely and efficiently participate in system restoration to accelerate the process.Focusing on the core issue of large-scale wind power participation in system restoration,this paper studies the determination method of maximum wind power integration capacity and integration time in black-start process of power system,establishes corresponding optimization solution models for different problems,and finally forms a set of assistant decision-making methods suited for large-scale wind power participating in system restoration.Main contributions of this thesis are described as following:1.The calculation method and application of dynamic wind power penetration limit(DWPPL)are studied.In order to improve the rapidity of power system black-start,as many wind power as possible should be involved in black start.First,the concept of DWPPL is proposed,which can represent the maximum capability of system to accommodate wind power at a certain moment in black-start process.Then,considering the disturbance of extreme wind conditions,the mathematical model and chance constrained programming method for solving DWPPL are presented.Next,considering the transient security of the system,the model is further improved and the corresponding accelerated solution method is proposed.Finally,the black-start scheme formulation method based on DWPPL is established,which provides decision support for maximizing the utilization of wind power to accelerate system recovery.2.The security margin analysis method of power system when wind power participates in black start is proposed.Starting from the security of black-start of power system,the large-scale wind power is considered to participate in the system restoration under the condition of ensuring the system security margin.First,the security margin evaluation indexes of wind power participating in black start are put forward based on the influence of wind power on the system recovery,which characterize the security level of the system accommodating a certain amount of wind power during black start.Then,considering the randomness of wind conditions,the historical simulation method is applied to generate future wind power output simulation sets,and the probability distribution column is used to represent the security margin value.Next,a method of security margin analysis of wind power participation in black-start based on probability distribution column is proposed.Finally,the method is applied to analyze the influence of wind conditions on power system security margin,analyze the influence of wind power integration capacity on power system seucurity margin level,and evaluate the impact of a wind farm on the power system security,which provides decision support for the safe use of wind power to accelerate system recovery.3.The black-start value evaluation of wind power and its application are studied.In order to take into account the security and rapidity of power system black-start and give full play to black-start value of wind power,first,this paper defines the black-start value function of wind power,based on the influence of wind power on the system recovery.The function can represent the black-start value of wind power in a certain period.Then,the conditional risk method is used to take wind power prediction error into account,and the method for evaluating the black-start value of wind power is obtained and applied to determine the wind power integration time and solve the optimal wind power integration capacity,which provides decision support for optimizing the utilization of wind power to accelerate system recovery.4.An optimization method for units’ restoration sequence of power system with high penetration wind power is proposed.To optimize the units’ restoration sequence of power system with high penetration of wind power,a bilevel programming model for units’restoration is defined firstly,which having taken multiple goals of the network reconfiguration into account.Then,the unit output characteristics in black start process are extracted,and a unified model of unit output in the network reconfiguration stage is established.Next,a scene simulation method of wind power output is given based on cloud similarity,to determine the effective output of the wind farm in the network reconfiguration stage.At last,the optimization process of units’ restoration sequence is proposed based on improved genetic algorithm.By optimizing the units’ restoration sequence,the appropriate wind power integration time in the process of system restoration is determined macroscopically.