Research On Security Classification And Comprehensive Evaluation Of The Active Distribution System

With the rapid development of power system and the growing demand for electricity,the scale of the power system is becoming larger and larger.And the shortage of traditional energy and the use of traditional energy sources bring threat to the human environment that people have to turn their attention and energy to the development and utilization of new energy,which led to the traditional distribution network return to the active distribution system.Analysis of the characteristics of active distribution system is important to master its operating status and to protect the safety of power supply.Therefore,based on the analysis of the characteristics on active distribution system,the evaluation of its safety is developed in this paper,and the economic and environment-friendly characteristics are analyzed to make a comprehensive evaluation of the operation of the active distribution system,the main work is as follows:Firstly,the characteristics of the active distribution system are analyzed,and the multi-properties ADS maximum power supply capacity solving model is proposed.The relevant constraints of DG and ESS are introduced in this model,and the nonlinear constraint is transformed into the cartesian product constraint form of the rotating cone,and the cone optimization model transformation is completed.The cone optimization method can improve the calculation speed and accuracy.Secondly,on the basis of calculating the total supply capacity,the safety margin,active load entropy,active regulation rate and active safety index are defined by the influence of distributed generation,active load and energy storage system on the safety of distribution network.Combined with the failure rate index and the restrictive indicators constitute the safety evaluation index system,which can description the safety of the grid operation from the horizontal,vertical and flexibility and other multi-angle of the ADS.Combined with these safety indexes,the security classification system is established,according to the importance of the load,the safety requirements of the grid are different,and different thresholds can be used to establish the safety level division method.Finally,the active load is optimized by particle swarm optimization algorithm,andthe charging and discharging strategy of the energy storage system is made by using the consistent active control method.The evaluation method proposed in this paper is used to compare the safety grade of the distribution network before and after optimization.By further analyzing of the economic indicators and the environmental indicators of the active distribution system,the ADS is analyzed by the extension theory and the operation information is provided for the dispatching department.