| Scientific and technological progress has promoted the intelligent development of power grids and the development of power grid automation.Naturally,the application technology of power distribution automation main stations and terminal equipment is also more perfect and mature than in the past,which has enabled the distribution automation system to have a better development prospects.Compared with the traditional distribution network,the intelligent distribution network system equipped with SCADA,feeder automation and advanced application functions has unique advantages.Based on a series of methods of quickly judging faults,diagnosing intervals,and isolating faults,the system can make real-time monitoring and rapid response to the operating state of the system.However,at present,the advantages of distribution automation systems in regulating and operating have not yet been fully demonstrated,especially in the calculation of the fixed value of distribution network demarcation switch protection,the main reason is that the adjustment of distribution automation terminal protection value is still very backward.The adjustment of the values reflected in the fixed values is empirically adjusted,and estimates or estimates are given against the historical experience table,that is,the adjustment is made according to a single line parameter,such as the length,and a value is estimated according to historical experience,resulting in imprecise or even erroneous fixed values.In actual operation,the imprecise or even erroneous value will cause the protection to move or refuse to move,which will cause a great risk to the operation of the power network.This method is no longer suitable for the existing accurate terminal equipment.An accurate calculation method and a platform for unified standardization and management of line parameters,values,etc.are urgently needed.The principle,calculation method,and model construction of the protection value of the distribution terminal are also urgently needed.At the same time,the distribution line has a wide variety of points and involves the number of distribution terminals and its huge size.Only by realizing the professional management of distribution terminal protection,scientific calculation of models,automatic calculation of fixed values,and intelligent review of fixed values,can the smart distribution network be effectively played its due role and improve the reliability of distribution network operation.Based on this situation,it is necessary to establish an intelligent terminal protection rating calculation system based on the latest computer network and software technology,meeting the latest standard technology system,facing the professional requirements of relay protection,and serving the distribution network.According to the demand of intelligent terminal system serving distribution network,this paper aims to realize the specialized management and professional guidance of the fixed value calculation of the terminal protection equipment of distribution network,based on the support of the existing terminal equipment of distribution automation system.By conducting written and field research on the principles of network allocation automation systems and organizing meetings of experts on power grids,a unified platform for the calculation of network allocation protection ratings has been established,and the corresponding platform and technical support for the calculation of protection ratings have been realized.Finally,it greatly improves the accuracy of the power distribution automation switch and has important practical significance for the development of the distribution network.With a network terminal protection calibration system,we have been able to effectively supervise and manage the whole process of the network switching protection calibration calculation,greatly improving the accuracy of the network terminal protection calibration results and the efficiency of the protection tuning calculation.The algorithm breaks through the traditional empirical estimate of the fixed calculation model,and through the establishment of the calculation model,the calculation of the fixed calculation is intelligent,and the precise calculation of the zero-order current of the distribution network distribution line is first solved.Based on this system,a sound management process has been established.Under the premise of improving the reliability and selectivity of the protection actions of the distribution network terminals,the work intensity and working hours of protection professionals and on-site protection and adjustment personnel have also been greatly reduced.According to the statistical results of Linyi Company,After the platform was applied,the total number of switch protection lists participating in the calculation and implementation of the distribution network terminal was 2,156,accounting for about 40%of the total number of network terminal switches.The overall correct operating rate of the terminal increased by about 30%,creating a large number of economic and social benefits for the grid.At present,the problem that needs to be solved further is to optimize and perfect the system and the protection calibration algorithm combined with the system usage and the actual operation effect of the distribution switch. |
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