Electrical System

Seoul Metro Line 9

The substation of Seoul Metro Line 9 receives 22.9kV alternating current from Korea Electric Power Corporation(KEPCO) substations and transforms it down into 1,500V direct current for rolling stocks. Then it is transformed down again into 220V or 380V alternating current in the electric room located at station for station facilities such as lighting, motor, etc. We have the most advanced electrical facilities as follows:

Gas Insulated Switchgear (GIS)
Gas Insulated Switchgear (GIS)

Since the major parts of GIS (Gas Insulated Switchgear) are air-tightened in metal houses filled with SF6 insulated gas so that they are not affected by surrounding contaminants and climate changes, its insulation does not break down due to prolonged hours of operation.
Besides, GIS is separated by each gas chamber so that electric faults inside GIS does not wide spread. Extra high voltage (22.9kV) and electric power incoming switchgear of substation is made up with GIS for simple maintenance and its stability.

Digital Distribution Panel
Digital Distribution Panel

Instead of conventional panel being composed of mechanical relays, analog meters, we have adopted the most advanced digital distribution panel for high reliability, stability, and convenience, etc in various parts by using digitalized relays.

Transformer on-line shear device

In case of a partial discharge which is caused by a poor connection in the closed power distribution unit or lowered dielectric strength in insulating materials, this equipment receives such electromagnetic waves and detects and diagnoses whether the power distribution unit has a problem through a live wire online.
As it is installed at the transformer panel of a substation, this device predicts any accident and preserves and prevents potential cases by managing heat deterioration at the substation through measurement on a real-time basis.

On-site transformer-Detector-Communications equipment-Comprehensive control office

Regenerative Power Device

We have achieved an efficient use of energy by using regenerative power of the train braking to power of adjacent train or station electrical installation.
We have two types of devices.

Regeneration Inverter
  • Regeneration Inverter
    The regenerative power is converted into alternating current through an inverter sent to the high-voltage distribution system and consumed in station electrical installation.
  • Regenerative Power Device(Battery type, B-CHOP)

Regenerative power is absorbed into the secondary battery(lithium ion) and re-used in power of train.

B-CHOP, 축전지, 시스템 개요