Research On Relay Setting Of Subway Power Supply System And Software Design

In recent years,the subway is constructed in(super)first-tier cities in full swing,and the structural design and corresponding protection configuration of the subway power supply system are becoming gradually towards maturity.In view of the diversity of the operation mode of the subway power supply system,The medium voltage network is usually equipped with overcurrent protection and zero sequence current protection as backup protection.The relay setting of the medium voltage network needs to take the coordination relationship between the upper and lower stages into consideration,which results in multiple setting value of relay protection for the medium voltage network.Offline setting is usually handled in the most extreme situation,which causes the task of relaysetting is becoming quite complicated and time-consuming.This paper firstly studies and analyzes the configuration and related relaysetting principles of relay protection in metro power supply system.As for the time coordination problem of medium voltage network in large section,shortening the time difference can not solve the problem fundamentally.Considering the threshold value provided by the power system,the solution is discussed respectively from the perspective of power supply system design and protection configuration.In view of the principles and methods of CIM model expansion in power system,the CIM model of relay protection for metro power supply system was expanded properly,and the preparatory work for online relaysetting was customized.Then the calculation formula of maximum load current of the single-loop power supply partition and the intersecting power supply partition group is deduced and analyzed based on the iterative method,which improves the accuracy of the load current calculation.Taking the grounding method of the medium voltage network into consideration,the general algorithms of various types of AC short circuit calculations are studied by considering various operating modes of the power supply system.The transient short circuit of the subway power supply system is simulated in MATLAB/Simulink,and the criterion of distinguishing the exit short circuit model and remote short circuit model is derived by using curve fitting method,the calculation formula is proximate to the simulation result,which provides theoretical basis for relay setting and checking.Analyzing the demand design based on UML,the design process of the relay protection setting software for the subway power supply system is expounded distinctly,the relay protection setting software for metro power supply system was developed successfully based on the platform of VS2010.Combined with practical project of the Guangzhou Metro Line 9,each function of DCRPS(Direct Current Relay Protection Software)has been tested,it has been delivered to the design institute,the good effect of its use verifies the practicality of this software.