Analysis On Model And Protection Characteristic Of Metro DC Power Supply System

In recent years,the rail transit in China has been rapidly developed as an important part of the urban traffic,and the reliablity to operation the DC traction power supply system plays a very important role in operating the rail traffic in safety.So it's of a far-reaching influence to carry out a research related to dc power supply system.First,the paper studies the DC traction power supply system in detail,especially the working principle of the latest equivalent 24 pulse rectifier unit.It also has analyzed the 24 pulse rectifier unit's work principle of subway and multiple linear external characteristic model,and established mathematical model by replacing DC traction substation with the Thevenin's equivalent circuit which contains ideal voltage source resistance.Then,it verifies the accuracy of the model by the methods that the Guangzhou metro line 6 tests 24 pulse rectifier unit's external characteristic in field.Secondly,this paper also introduces in detail the dc traction power supply system,the protection configuration principle of dc traction power supply system for metro passenger rush hour feeder protection device of the phenomenon of overload trip frequently,in order to guarantee the traction power supply reliability of the rush hour,in confirm the protection operation reasons and no more than the premise of dc feeder switch over current limit value,to increase the dc switch large current trip setting,adjust the over current protection setting value and the current rising rate di/dt and current increment of delta related measures of protection parameters,I make the dc feeder protection Settings and traction load current peak matching.At last,in dc current protection setting value and the traction load current matching under the premise of considering the future metro development,increase in traffic density and traffic capacity,under the condition of given dc feeder can adjust the scope of protection setting values and the matching relation between traction load current with changes,the matching principle,to provide reference for similar project.The matching test of dc switching load current of multiple traction power supply stations in guangzhou metro line 2 and dc feeder protection setting value is carried out to verify the feasibility of the matching principle.Combined with nearly four years of guangzhou metro line 2 dc feeder switchgear protect alarm or trip case,dc traction power supply system for metro passenger rush hour feeder protection device of the phenomenon of frequent overload trip,by size/road mode of electric buses for flow test,analysis of parameter setting range cooperate relationship,with the condition of electric buses take flow protection adjustment parameter matching method was proposed,for the future of dc traction system provided a reference for the protection of the adjustment.