Preventing GIS gas valve mis-operation at a KEPCO substation with self-powered valve open/close detection sensors · Field Cases

Site: KEPCO (Korea Electric Power Corporation) substation

Self-powered sensors were added to the gas valves of a substation GIS (gas-insulated switchgear) so that the open/closed status of each valve can be monitored remotely in real time.

1. Purpose

Preventing huge losses caused by operator valve mis-operation.
If a gas valve of a GIS in operation is operated by mistake, insulation breakdown can cause a wide-area power outage.
GIS gas valve mis-operation accidents occur on average twice a year (average recovery cost approx. KRW 200 million).
Cause: no remote monitoring of the valves, and the open/closed status is hard to check by eye.
A wireless, self-powered GIS gas valve open/close monitoring system was needed.

2. Benefits

Real-time remote monitoring of the open/closed status of substation GIS gas valves.
Only the self-powered sensor unit is added to the GIS valves already installed at the substation (lower installation cost).
Prevents outages caused by GIS gas valve mis-operation and reduces maintenance costs.
Applicable to about 800 KEPCO substations in Korea (about 500 gas valves).
Also applicable to the in-house power generation systems of medium and large plants.

3. System configuration

Self-powered valve open/close detection — Generates its own power when the valve is opened or closed and sends an RF signal
Signal Monitor (receiver) — Shows a unique number for each signal; linked via RS485
Relay module and LCD display (contacts) — Receives the RS485 signal from the Signal Monitor, shows it on the LCD and passes it to SCADA as contact signals
SCADA — Monitors whether each valve is open or closed

4. Product specifications

Self-powered Valve Open/Close Detection Sensor (MWSG-100)

Size: W73 × D47 × H84 mm
Frequency: 920.700 MHz (FSK)
Antenna: Built-in antenna
Transmission range: Approx. 100 m (open field)
Power: Self-powered (no battery)
Dust / water protection: IP57 (water-resistant for everyday use)

Signal Monitor (MWSM-700)

Size: W258 × D107 × H34 mm
Weight: 497 g
Frequency: 920.7 / 447.9 MHz (FSK)
Antenna: External antennas × 2
Transmission / reception range: Approx. 1 km (open field)
ID registration: Up to 999
Display: FND 5-digit, LED
External terminals: RS-485, warning light, speaker, power
Power: DC 12 V, 1 A adapter

RTU Relay

Size: W200 × D111 × H60 mm
Communication interface: RS485
Relay channels: 16
RS485 connection: 1 – 255 modules can be connected
Contact rating: 10 A 250 VAC / 30 VDC or less
Power: 5 V 2 A

5. Installation photos

▶ Self-powered GIS valve sensors installed in the substation

▶ LCD and relay module installed in the substation

Contact

MPIA Co., Ltd. · Tel. +82-32-666-8193 (8191) · Weekdays 09:00 – 18:00 (KST)
mpia@mpiatek.com · www.mpiatek.com