This paper presents a model of the metro power supply system by MATLAB/SIMULINK/PSB and performs the simulation for the dynamic responses of the system under short circuit from short and long distances respectively.

So analysis and improve the reliability and safety of the metro power supply system has come to more attention.

Analysis of leak current DC power system of opencast mine;

Using the knowledge of linearity algebra, the dynamic mathematical model for metro traction power system is founded as per the actual requirement of engineering.

Coordination of line detection with automatic re-closing in DC traction power supply systems

After analyzing several kinds of protection for feeder line in subway DC traction power supply system,it is pointed out in the paper that the phenomena of refusing action and error action can not be avoided with existing protection which can not protect the whole feeder line.

The paper gives the examples of failures caused by rail potential and negative return current occurred in operation of Guangzhou subway, illustrates the specialty and importance of rail potential and negative return current in DC traction power supply system after the analysis of causes in detail and proposes some inspection and handling measures to typical failures in operation.