Su-Gil Lee

High frequency partial discharge measurement by capacitive sensor for underground power cable system

This paper deals with partial discharge (PD) measurement technique on the range of high frequency by capacitive sensor for the power cable system. This sensor is installed inside of cable joints and terminations without affecting the insulation design. The sensitivity of the sensor depending on the installation condition was investigated by simulation and compared with the results of experiments with joint occurring PD. It was shown that the dominant factor affecting sensitivity of the sensor was resistance formed between sensor and ground sheath. It was proven that the sensitivity of this sensor was much higher than that of the conventional method in accordance with IEC270 standard. This sensor is available for the on-line PD monitoring system.

A study of train braking energy saving simulation for conventional line

The influence of logistics on the national economy increases as the economy advances. Vehicle transportation, however, cannot meet the ever-increasing transportation demand, with its economic efficiency deteriorating over time. Judging that such transportation demand cannot be met only by vehicle transportation, the government also seeks to increase transportation through railroads. In this study, the voltage supplied to TTX in trial operation was monitored and analyzed to identify the voltage condition supplied by the existing railroad. To directly measure the voltage supplied to TTX, PT was installed at the bottom of TTX pantograph for monitoring the primary voltage of the transformer, and for accurate measuring, surrounding environment and conditions were recorded and the analysis of stringing voltage using CBEMA curve was conducted. As a result, some of the section on Honam, Jonngang and Taebaek line were supplied 110[%] pf rated voltage (25[kV]) for more than 200[s] frequently exceeding 110[%] Taebaek line appeared to have had the installed voltage in worst condition.

A Study on Traction Motor Characteristic in EMU Train

The main transformer of the train is the equipment that receives the AC 25KV power from the trolley wire and transforms it to an adequate voltage that can be used by the traction control system of the train. The primary winding side is the trolley wire voltage; the secondary winding side is the load side that supplies power to the main motor through the traction control system (Converter/ Inverter); the third winding side is the load side that supplies power to SIV that provides the service units of the train with power, which includes loads such as train air conditioning and ventilators, composed of multiple winding transformer. The main circuit system of the secondary winding is 2 parallel and 1 serial. Mcp 1 car and M cars have one traction control system which has 2 sets of converter/inverter to which the main transformer supplies power.

A study of train braking energy for energy bank design

The influence of logistics on the national economy increases as the economy advances. Vehicle transportation, however, cannot meet the ever-increasing transportation demand, with its economic efficiency deteriorating over time. Judging that such transportation demand cannot be met only by vehicle transportation, the government also seeks to increase transportation through railroads. In this study, the voltage supplied to train in trial operation was monitored and analyzed to identify the voltage condition supplied by the existing railroad. To directly measure the voltage supplied to train, PT was installed at the bottom of train pantograph for monitoring the primary voltage of the transformer, and for accurate measuring, surrounding environment and conditions were recorded and the analysis of stringing voltage using CBEMA curve was conducted. As a result, some of the section on Honam, Jonngang and Taebaek line were supplied 110[%] pf rated voltage (25[kV]) for more than 200[s] frequently exceeding 110[%] Taebaek line appeared to have had the installed voltage in worst condition.

Relation between Induced Voltage of Rail and Feeding Line of Wireless Power Transfer System for Railway Application

The magnetic field generated by the feeding line of a wireless power transfer system induces voltage on the rail of a railway system. The induced voltage of the rail can have a bad influence on the track circuit and on safety. This paper simulated three feeding lines to study the relation between the feeding lines and the induced voltage of the rail; it also proposed magnetic field distribution of the feeding line to reduce the induced voltage.

The study of carbody control for conventional train

Tilting trains are now an established feature of railway operations throughout the world. For intercity traffic, tilt provides operators with increasing speeds, and therefore enhanced competitiveness, on existing routes where insufficient traffic or a lack of funds precludes the construction of a dedicated new high-speed railway. Appling the tilting train, we can expect 30% of speed up on existing lines, but the stability of the electric current would be low because of tilting the train. Also, the spark between the catenary and pantagraph cause environmental problems such as noise, radio wave malfunction. Therefore, the tilting on pantagraph for the power suppling device is very essential for stable electric power supply.

A study on regenerative breaking energy on electric multiple unit train

Korean-style EMU(Electric Multiple Unit) train which was developed by Korea Railroad Research Institute (KRRI) has been in trial operation on Honam, Jonngang, Choongbuk and Taebaek line. In this study, the voltage supplied to EMU Train in trial operation was monitored and analyzed to identify the voltage condition supplied by the existing railroad. To directly measure the voltage supplied to EMU Train, PT was installed at the bottom of ttain pantograph for monitoring the primary voltage of the transformer, and for accurate measuring, surrounding environment and conditions were recorded and the analysis of stringing voltage using CBEMA curve was conducted. As a result, some of the section on Honam, Jonngang and Taebaek line were supplied 110[%] pf rated voltage (25 [kV]) for more than 200[s] frequently exceeding 110[%] Taebaek line appeared to have had the installed voltage in worst condition. The analyzed data is expected to be helpful in stabilizing the power system and power conversion system of train which will run Jonngang and Taebaek line.

A study of train ride comfort control for conventional curve line

Train ride comfort control of tilting train are now an established feature of railway operations throughout the world. For intercity traffic, tilt provides operators with increasing speeds, and therefore enhanced competitiveness, on existing routes where insufficient traffic or a lack of funds precludes the construction of a dedicated new high-speed railway. Appling the ride comfort control train, we can expect 30% of speed up on existing lines, but the stability of the electric current would be low because of ride comfort control train. Also, the spark between the catenary and pantagraph cause environmental problems such as noise, radio wave malfunction. Therefore, the on pantagraph for the power suppling device is very essential for stable electric power supply.

A Study on the Design Procedure of the Eight Pole Magnetic Bearings for the Inner-rotor and the Outer-rotor Type

This paper presents design procedure of the magnetic bearings used for high-speed electric machines and flywheel energy storage systems. Magnetic bearing can be categorized by inner- rotor type and outer-rotor type according to the position of the rotary disc. These two types are applicable based on application environments such as application space, required attraction force, and controllability. Magnetic bearing is generally designed based on the ratio (geometrical coefficient or geometrical efficiency) of pole width to rotor journal radius but proper ratio is only decided by the analysis. This is the difficulty of the magnetic bearing design. In this paper, proper design technology of the inner-rotor type and outer-rotor-type eight pole magnetic bearings is introduced and compared with the FEM analysis results, which verifies the proposed design procedure is suitable to be applied to the design of the magnetic bearings for the industrial applications and flywheel energy storage system

The study of tilting actuator control for Korea tilting train

Tilting trains are now an established feature of railway operations throughout the world. For intercity traffic, tilt provides operators with increasing speeds, and therefore enhanced competitiveness, on existing routes where insufficient traffic or a lack of funds precludes the construction of a dedicated new high-speed railway. Appling the tilting train, we can expect 30% of speed up on existing lines, but the stability of the electric current would be low because of tilting the train. Also, the spark between the catenary and pantagraph cause environmental problems such as noise, radio wave malfunction. Therefore, the tilting on pantagraph for the power suppling device is very essential for stable electric power supply.