Underground Line
Pad Mounted CB & Switch
Features
Where it is installed in 25.8 kV underground distribution line, RMU(Ring main unit) can protect several electric devices and equipments by tripping the circuit breaker against from over current, short-circuit current, and any kind of earth faults.
RMU is designed for distribution automation system with combination of circuit breaker, load break switch and direct circuit.
Multiple selection of load break switches and circuit breakers make the end user’s distribution line system more flexible.
SF6 gas insulated switchgear will provide full support with various choice of controls in order to complete distribution line system.
Outline dimensions
| No. | NAME | MATERIAL | QUANTITY |
|---|---|---|---|
| 1 | MAIN BODY | SUS304 | 1 |
| 2 | BASE | SUS304 | 1 |
| 3 | OUTDOOR ENCLOSURE | SUS304 | 1 |
| 4 | P.T | – | 1 |
| 5 | P.T CABLE | – | 1 |
| 6 | GROUNDING DEVICE | C1100 | 1 |
| 7 | EARTH BOLT | SUS | 14 |
| 8 | WATER LEVEL SWITCH | – | 1 |
Ratings
| Ring Main Circuit Breaker | JWRMU-4W-2020 | JWRMU-4W-6020 |
|---|---|---|
| Basic Ratings | ||
| Rated Voltage(kV) | 24 | |
| Rated Frequency(Hz) | 50 / 60 | |
| Making & Interrupting Capacity – CB | ||
| Rated Normal Current(A) | 200 | 200 / 600 |
| Rated Short-Circuit Making Current (peak) | 31.5 | |
| Rated Short-Circuit Making Current (rms) | 12 | |
| Rated Cable-Charging Interrupting Current(A) | 15 | |
| Rated Magnetizing Switching Current(A) | 21 | |
| Making and Breaking Capacity – LBS | ||
| Rated Normal Current(A) | 600 | |
| Number of Load Current Operations- Main(times) | 100 | |
| Short-time Withstand Current – Main & Earth | 12 kA / 1 sec | |
| Short Circuit Making Current (peak) – Main & Earth(kA) | 31.5 | |
| Number of Making Operations – Main/Earth(times) | 5 / 3 | |
| Rated Cable-Charging Interrupting Current(A) | 15 | |
| Rated Magnetizing Switching Current– Main(A) | 21 | |
| Insulation Level | ||
| Power Frequency Withstand Voltage | 60 kV / 1 min | |
| DC Voltage Withstand Voltage | – 78 kV / 15 min | |
| Lighting impulse withstand voltage (1.2×50μs) (kV) | 125 | |
| Interruption & Insulation Medium | ||
| Arc Extinction Medium | SF6 Gas / Vacuum | |
| Insulation Medium | SF6 Gas | |
| Operation Performance | ||
| Close / Open DC Voltage – CB & LBS | 24 Vdc | |
| Mechanical & Electrical Endurance – CB(times) | 10000 | |
| Mechanical Endurance – LBS / Earth SW(times) | 5000 / 1000 | |
| Operating Temperature – CB & SW | -10∼75 | |
| SF6 Gas Pressure | ||
| Nominal Pressure(kgf/cm2 G) | 0.7 | |
| Bursting Pressure(kgf/cm2 G) | 1.8∼2.0 | |
| Minimum Gas Pressure(kgf/cm2 G) | 0.3 | |
| Leakage Rate(cc/sec) | 2.6 x 10-7 | |