Design And Implementation Of Sensitive Load Voltage Sag Withstand Capability Quantization Evaluation System

In power system,voltage sag refers to the power quality phenomenon that the supply voltage is reduced due to short circuit fault,large motor start-up,transformer inrush current,etc.,and the voltage is restored after a short period of time.Voltage sag has a very obvious impact on sensitive load equipment,which will cause these equipment shutdown or failure.So voltage sag is a serious threat to the power supply quality of power system.A lot of researches have been carried out on the quantitative evaluation of voltage sag and the failure rate evaluation of sensitive load equipment domestic and abroad.However,in terms of voltage sag and related information automatic quantitative evaluation,there are still many domestic power enterprises failed to achieve.In this thesis,based on the project of quantitative assessment system of voltage sag tolerance capability of sensitive equipment to access point organized by Sichuan electric power company,the detailed functional design and development of the system are carried out by comprehensively using the related knowledge and technology of electrical,as well as the related technology and tools of computer software development.The system can provide tool support for power supply quality assurance of the company through quantitative evaluation of voltage sag of sensitive load and inrush current of transformer.In the research work,the research trends and current situation of voltage sag sensitivity evaluation methods and tools at home and abroad are analyzed firstly.Then,the definition,characteristics and evaluation principle of the voltage sag tolerance of the equipment,as well as the.Net web technology and MVC software design mode used in the development of the system are studied.Based on the analysis of current situation,theory and technology,the detailed function and performance requirements of the quantitative evaluation system of voltage sag withstand capability of sensitive load to access point are presented,and the overall development goal of the system is proposed.According to the research of the system requirements,the overall technical scheme and database of the system are designed.At the same time,according to the relevant technology and principles in the electrical field,the voltage sag evaluation model of sensitive load to the access point and the voltage sag evaluation model of transformer inrush current are designed,and the model is simulated and verified.Based on the overall function design and database design of the system,this paper designs and implements three modules in detail,which are system operation parameter management,voltage sag evaluation of sensitive load to access point and voltage sag evaluation of transformer inrush current.Finally,by analyzing the test environment and test methods of the system,this paper introduces some functional test cases of the system,bug detection and correction of functional test,and tests and verifies the performance of Web services of the system.The results of function and performance test show that the system meets the development requirements of Sichuan electric power company in function and performance.At the same time,the efficiency and accuracy of the voltage sag evaluation model of the access point and inrush voltage sag evaluation model of the transformer for the sensitive load in the system also meet the expected requirements.The application of the system provides a convenient voltage sag assessment automation tool for the relevant users of the company,improves the work efficiency,and promotes the quality of power supply quality assurance work of the company.