Substation Automation

Bus protection IED(STP-K120)

Bus protection IED(STP-K120)

Protect electronic relay by detecting breakdown on 345kV main electronic line and swiftly separating the main electronic line with breakdown. Customized interface is provided with convenient usage by utilizing 7'' TFT LCD equipped with touch screen.


  • Voltage differential motion protecting function to use total vector in current of circuits connected on main electronic lines
  • Voltage differential motion from non-linear resistor (High Impedance Differential Protection)
  • Breakdown detecting elements based on low pressure (UV/UVS/UVD)
  • CT Failure Detection and alarm
  • PT Failure Detection and alarm
  • Lock on the operation of relay and alarm according to the results of frequent monitoring

General Specification

Division Item Specification
Terms of use Ambient temperature -25℃ ~ +55℃
Relative humidity 10% ~ 90%
Elevation 1,500m less than
Rated Frequency 60Hz
Electric current 5A
Voltage 115/√3 V
Power DC 125V (90~140V)
Auxiliary power source Single phase 220V
Outward form Size 280 x 255 x 247mm (W x H x D)
Form Stand-Alone Type
Weight 8.0kg less than
Quality of the material Aluminum

Hardware Specification

Division Specification Note
Communication port Ethernet 100Base-FX, 2 channels
connector : ST type, Multi-mode, 1310nm
IEC 61850
100Base-T, 1 channels , Twisted-pair TCP/IP
Console(front) Serial 9pin (Male-Type) 1 port Operational Software
Time sync. IRIG-B 120 or SNTP
Console(back) Serial 9pin (Male-Type) 1 port Reserve
Enter Contact 24 points
Contact output 28 points
CT 8 channels
PT 5 channels
Display TFT Color Graphic LCD 7" (800 x 400)
Button 18
LED 26

Apparent Dimension