Research On On-line Checking System Of Grid Rel Ay Protection Settings

As an important part of ensuring the safe and stable operation of power grid,relay protection is of great significance for its rapidity and accuracy.Under the background of the current flexible operation mode of power system and the continuous improvement of user demand for electricity,the requirement of power system relay protection is getting higher and higher.However,the traditional fixed value is set under the maximum operation mode,while the protection performance is checked under the minimum operation mode.In this way,the fixed value of protection can’t meet the requirements of real-time power grid operation,resulting in misoperation or rejection of protection and power grid accidents and economic losses.In this context,it is particularly important to check the value of protection online.First of all,this paper analyzes the principle of online checking for the fixed value of relay protection,and studies the setting principle and checking principle of docking distance protection according to the actual operation rules of power grid.Secondly,the software module function and realization scheme of the relay protection fixed-value online checking system developed by North China Electric Power University are studied and analyzed,and the fixed-value online checking scheme based on itemized indexes is proposed.Combined with the dispatcher’s requirements for online calibration of fixed value,this paper develops the switching function of automatic identification of power grid operation mode changing fixed value.In order to solve the problem that the dispatcher checks the current operation mode to determine whether the value is unreasonable,the protection check function condition is screened :(1)must be able to reflect the change of operation mode;(2)function modules must be fully automated;(3)the generated report is easy to understand;(4)the calibration algorithm can meet the real-time requirements.In this paper,the developed module in the system analyzed one by one,finally determine the dispatcher online relay protection check function modules as follows: the protection sensitivity calibration module,setting protection device and cooperate with fastest protection device to remove fault check as selective check module,the automatic recognition operation mode switch fixed value area check protection setting module and read the scene real-time calibration module,as well as the analysis of the specific scope of protection setting visualization module.Taking the actual power grid as the research object,the power grid resources are maintained,and protection values are checked by various indexes.The accuracy of the report is verified through analysis,which plays a positive role.