Operation Risk Assessment Of Distribution Network Considering Line Failure And Renewable Energy Access

With the large-scale integration of renewable energy in the distribution network,the scale of the power system is gradually increasing,the number of power distribution equipment is increasing,and the topology of the distribution network is becoming more and more complicated.The renewable energy power generation device connected to the system Because of the randomness and volatility of its output,it may bring uncertain risks to the distribution system.At the same time,the probability that the distribution line may fail is increasing,and the uncertainty of the distribution system continues to increase.The safe operation of the distribution network has a negative impact.Therefore,it is increasingly important to assess the operational risk of the distribution system’s line failure rate and the access of renewable energy to the distribution system.In the context of the various factors that affect the failure rate of distribution lines and the access of renewable energy to the distribution network,this article first analyzes the impact on the distribution network,and establishes the load loss index and the voltage limit index for the distribution network.And the distribution network operation risk index system of the branch power flow over-limit index.Secondly,the modeling of distribution network line failure rate,the correlation modeling of renewable energy output,and the solution of distribution network system state variables are studied respectively.Finally,the quantified calculation of the operation risk index of the distribution network is carried out.The main work of this paper includes:(1)Based on the evaluation theory of distribution network operation risk,this article analyzes the various factors that cause the distribution network line failure.Secondly,discuss the various risks brought by the access of renewable energy in the distribution network to the system,combining the operational risks brought by the failure of the distribution line and the operational risks brought by the access of renewable energy to the system.The operation risk assessment index of the distribution system including the node voltage branch power flow and the loss of load risk is provided for the quantitative calculation of the system operation risk under the different operating conditions of the distribution line and the system operation risk under the consideration of the different operating conditions of the distribution line in the following text The evaluation lays the theoretical foundation.(2)Analyze and discuss the factors affecting the failure rate of distribution lines based on the statistics of distribution line operation and fault data based on multiple data platforms.Establish time-varying fault models of distribution lines based on different working conditions,and a proportional risk model that considers multi-dimensional distribution line operating data.In order to classify the operating conditions of distribution lines more reasonably,neural network algorithms are used to classify the operating conditions of distribution lines according to the operating data of the distribution lines,and oversampling technology is used to improve the balance of the distribution line data samples.The proportional risk model is improved based on the distribution line operating data corresponding to different operating conditions of the distribution line.Finally,taking the historical data of the actual distribution network in a city as an example,two distribution line failure rate models are used to calculate the distribution line failure rate and load loss index.(3)Aiming at the randomness of renewable energy output and the correlation with regional renewable energy output,a set of correlation modeling methods applicable to multiple renewable energy sources are proposed.A piecewise linearized power flow calculation method based on K-means clustering is proposed in view of the impact of renewable energy access on the fluctuation of system state variables.When the distribution network is connected to multiple renewable energy power generation,piecewise linearity is adopted.The standardized method quickly solves the system state variables,calculates the relevant risk indicators for the fluctuation of the state variables,and takes the IEEE33-node system as an example,and uses the traditional Monte Carlo algorithm to compare and test the accuracy of the algorithm proposed in this chapter.The calculated system state variables are used to solve the corresponding system operation risk indicators to provide a basis for scheduling decision-makers.