A Study on the Protection Relay Test and Analysis Method of AC Electric Railway Substation

Since opening of the Korean high-speed railway in 2004,the rate of electrification has been increasing rapidly,and safety of the supply of AC railways has become very important.And the digital protection relays in railway feeding system need more attention with the expansion of unmanned SSs(substations)and digital SSs.For accident prevention,it is necessary to develop accurate modeling and simulation technology for railway feeding devices of electric railway.And it is also important to continuously improve test methods and develop excellent relay algorithms and apply them to the protection system to prepare for unexpected accidents.In this study,after reduced modeling the AC railway power supply system using PSCAD/EMTDC(Power Systems Computer Aided Design/Electromagnetic Transient DC Analysis),the results were compared and verified with the numerical calculation using the symmetric coordinate method.It also presents a method of using the verified results for simulation and education for various railway accidents.This study result will be used for the construction of new lines as well as existing lines in the future railway business.

Fault Detection and Protection System of Electric Railway Substation

The industrial power systems are moving to digital networks,and unmanned systems are increasing recently with the technological development of information and communication technology.In particular,reliability of system operation is very important for stable power supply.Most industrial power distribution facilities use a 154 kV or 22.9 kV extra HV(high voltage)power system,and a special monitoring system is required because a large loss occurs when an error occurs in the power facility in the field.Although digital protection relay(IED;intelligent electronic device)and FR(fault recorder)are applied to the field to protect the power system,various improvement activities are still ongoing.In this paper,a 22.9 kV high-voltage panel and its test bed,which are widely used in railway stations,tunnels,substations and large plants,were tested as test subjects.The developed fault detection system automatically starts the AL(auto-lock)circuit or outputs an alarm signal to user by monitoring in real time problems such as CT(current transformer)-open and poor-contact that the existing digital protection relay cannot cover.In addition,it is intended to increase the safety and reliability of the power system by blocking various accidents in the system in advance and accurately analyzing the causes of faults with the developed fault detection system.