Analysis And Evaluation Of Industrial Process Interruption Based On PIT Uncertainty

Voltage sag,short duration interruption and long duration interruption have become very serious power quality problems in modern power systems,and it is necessary for modern industrial users to study their analysis methods and evaluation methods.Combining the action sequence of relay protection device,immunity time curve of industrial process and connection relationship of sensitive equipment in industrial process,the severity evaluation of voltage sag,short duration interruption and long duration interruption can make the evaluation method more reasonable and refined.This paper conducts research from three aspects:the analysis of the action sequence of protective relaying devices and the impact of industrial users,the evaluation method of the severity of voltage sag in the industrial process of single-sensitive equipment,and the evaluation method of the severity of the failure of the industrial process of multiple sensitive equipment.Firstly,an analysis method of industrial users affected by distribution network failure is proposed.When the distribution network fails,the voltage change curves of various industrial users after the failure are obtained by analyzing the action sequence of relay protection devices when different branches fail.According to the voltage change of industrial users,the process parameters change of industrial process is analyzed,and the uncertain region of process immunity time of industrial users is further divided,which shows that industrial users are affected by faults.The practicability of the proposed analysis method is verified.Then,the voltage sag severity of single sensitive equipment industrial process is evaluated.In this paper,voltage sag events are divided into intervals according to voltage sag values,and combined with the uncertain interval of voltage sag duration and process immunity time in each interval,the severity index of duration based on process immunity time is proposed.The maximum entropy theory is adopted to establish the evaluation model of voltage sag severity in industrial process,and the interruption probability of single sensitive equipment industrial process is obtained,which can reflect the voltage sag severity in industrial process more accurately and reasonably.The rationality of the method proposed in this chapter and the superiority of higher evaluation accuracy are verified by the analysis of an example.Finally,a method for evaluating the severity of fault impact of multi-sensitive equipment on industrial processes is proposed by comprehensively considering the impact of distribution network faults on industrial users,the severity of voltage sag in industrial processes with single sensitive equipment and the connection relationship of sensitive equipment in industrial processes.Compared with the traditional evaluation method,this method analyzes the weak links of industrial process,comprehensively considers the influence of voltage sag,short duration interruption and long duration interruption,and then evaluates the annual industrial process interruption times caused by the first voltage sag,short duration interruption,second voltage sag and long duration interruption.The feasibility of the proposed evaluation method is verified by analyzing the industrial process of industrial user FET-LCD.