Description
The KENJING KJGG solid-insulated RMU is a fully sealed medium-voltage switchgear platform for primary and secondary distribution. Live parts are epoxy-encapsulated for touch-safe operation and stable dielectric margins in dust, humidity, or salt-spray environments. A three-position isolator (Close–Open–Earth) works with a vacuum interrupter to provide visible isolation, fast fault clearing, and safe earthing. Factory-configured five-prevention interlocks coordinate the main switch, isolator, earthing switch, lower door, and truck/compartment access to eliminate mis-operation.
Technical Highlights
- Voltage classes: 12 / 18 / 24 kV | Frequency: 50/60 Hz
- Rated current: 630 A
- Short-time withstand: 20 kA/4 s or 25 kA/4 s | Peak withstand: 50/63 kA
- Short-circuit breaking (vacuum): 20/25 kA
- Dielectric levels (typ.): 1-min power-frequency 42/48/50/55/60/65 kV; LIWV 75/85/88/100/125/145 kV (phase-to-phase/earth/across isolation)
- Partial discharge: ≤ 65 pC | Loop resistance: ≤ 150 µΩ
- Mechanical life: Isolation/Earthing ~3,000 ops; Circuit breaker ~10,000 ops
- Ingress protection: Up to IP67 for insulated parts; enclosure up to IP4X (per model)
- Operating window: −15 °C…+40 °C, RH daily avg ≤ 95%, altitude ≤ 1,000–2,000 m (application-dependent)
Mechanism & Construction Advantages
- Main switch drive: Four-link transmission with reclosing capability; compact DC permanent-magnet motor (planetary reduction) ~3% loss; dual-spring precision train; hardened steel gears with needle-bearing core for high impact resistance and long life.
- Isolator design: Torsion-spring, bi-directional energy storage with rigid bi-directional limits to prevent rebound; German Mubea disc springs maintain contact pressure; 125 mm air gap across isolation for insulation reliability.
- Fully insulated & sealed primary with plug-in cable terminations and insulating bushings ensures compact footprint while meeting creepage/clearance.
- Modular architecture: PT cabinet, incoming/outgoing line, and combined units (C/F/V/CFV) support two-in/two-out and two-in/four-out schemes; side/top busbar extensions simplify future expansion.
- Automation-ready: Optional DTU enables measurement, protection, and remote control/communication.
Typical Configurations (from application plans)
- PT cabinet (single-tank) for measurement and aux power, with XRNP primary fuse option
- V-cabinet with vacuum circuit breaker, three-position isolator, and earthing switch
- F-unit (load switch + fuse) or CFV common-tank combinations for feeder protection and compact substation layouts
Applications
Urban distribution, commercial centers, industrial parks, transport hubs, renewable interconnections—anywhere compact medium-voltage switchgear with high availability and strict operator safety is required.
Standards
Designed and tested to the relevant IEC series for MV switchgear and components (e.g., IEC 62271, IEC 60529) and associated CT, insulation, and protection device standards.
| NO. | Item | Unit | Parameter | ||
| 1 | Rated Voltage | kV | 12 | 18 | 24 |
| 2 | Rated Frequency | Hz | 50/60 | ||
| 3 | Rated Current | A | 630 | ||
| 4 | Rated Short-time Withstand Current | kA/s | 20/4 25/4 | ||
| 5 | Rated Peak Withstand Current | kA | 50 63 | ||
| 6 | Rated Power Frequency Withstand Voltage(Phase-to-Phase, Phase-to-Earth, Across Isolating distance) | kV | 42/48 | 50/55 | 50/65 |
| 7 | Rated Lightning Impulse Withstand Voltage(Phase-to-Phase, Phase-to-Earth, Across Isolating distance) | kV | 75/85 | 88/100 | 125/145 |
| 8 | Rated Short-Circuit Breaking Current | kA | 20 25 | ||
| 9 | Rated Short-Circuit Making Current | kA | 50 63 | ||
| 10 | Partial Discharge | PC | ≤ 20 | ||
| 11 | Temperature Rise | K | ≤ 65 | ||
| 12 | Mechanical Life(Isolation/Earthing Switch/Circuit Breaker) | time | 3000/10000 | ||
| 13 | Loop Resistance | μΩ | ≤ 150 | ||
