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High Quality Ring Main Unit Components for Reliable Power Distribution
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33KV Vacuum Circuit Breaker with Isolating Switch
As a professional China manufacturer, Cotenele International Trade (Wenzhou) Co., Ltd. provides specialized solutions for medium-to-high-voltage switchgear. The featured product—the KDV-40.5/630-20 Series 33kV Vacuum Circuit Breaker with Isolating Switch—is widely utilized in eco-friendly medium-voltage switchgear, Ring Main Units, and power distribution systems. This integrated assembly combines a vacuum circuit breaker with an isolating switch, offering numerous advantages such as ease of installation and a long service life.
33KV Circuit Breaker Mechanism with Isolation Mechanism
China manufacturers Cotenele’s KDVM-40.5/630-20-X series 33KV Circuit Breaker Mechanism With Isolation Mechanism delivers fast, reliable spring-operated switching, high durability over 10,000 cycles, mechanical interlock with disconnectors, and eco-friendly operation. Ideal for buyers seeking safe, maintenance-free medium-voltage switchgear solutions.
33KV Indoor Medium Voltage Load Break Switch
The China manufacturer Contenele's KDK-40.5D/630-20 series 33KV Indoor Medium Voltage Load Break Switch is designed for reliable, safe, and environmentally friendly power distribution in industrial, commercial, and utility applications. Compliant with Chinese national standards GB 3804-2017, GB 16926-2009, and GB/T 1985-2023, this switch features high short-circuit withstand capability, long mechanical life, and low maintenance requirements. It is an ideal choice for indoor switchgear and medium-voltage power distribution system procurement, ensuring safe isolation, operational flexibility, and sustainable power management.
22KV Medium Voltage Vacuum Circuit Breaker with Disconnector
This 22kV Medium Voltage Vacuum Circuit Breaker with Disconnector is a reliable solution designed by Cotenele, a professional China manufacturer, specifically for modern power distribution systems. Vacuum circuit breakers and disconnectors each have different functions; their combined use creates a powerful synergistic effect, playing a crucial role in ensuring the stable and efficient operation of the power grid.
11KV Medium Voltage VCB Circuit Breaker with Isolating Mechanism
The 11KV Medium Voltage VCB Circuit Breaker with Isolating Mechanism is a reliable, eco-friendly solution for power distribution systems. Manufactured by Cotenele in China, it ensures safe, fast, and durable switching operations, with a mechanical lifespan exceeding 10,000 cycles. Widely used in GIS, RMU, and air-insulated switchgear for metro, railway, petrochemical, and industrial projects. Compliant with GB1984-2014 and GB/T1985-2023 standards.
22KV Medium Voltage Circuit Breaker Isolation Mechanism
The 22KV Medium Voltage Circuit Breaker Isolation Mechanism by Cotenele International Trade (Wenzhou) Co., Ltd is a high-reliability operating solution for incoming feeders in RMUs. Designed in China, it ensures precise switching, mechanical longevity over 10,000 operations, and full compliance with international standards. Trusted by power utilities and industrial clients worldwide.
Common Ring Main Unit Components
Primary Circuit Components
- Vacuum Circuit Breaker (VCB)
- Load Break Switch (LBS)
- Disconnector (Isolator)
- Earthing Switch
Protection and Measurement Components
- Current Transformer (CT)
- Voltage Transformer (VT)
- Fuses
- Surge Arrester
Control and Indication Components
- Operating Mechanism
- Interlocking System
- Voltage Presence Indicator
- Secondary Terminal Blocks
Insulation and Support Components
- Insulators
- Bushings
- Solid or Gas Insulation Structural Parts
Key Switching Devices in RMU Systems
Vacuum Circuit Breaker (VCB)
A Vacuum Circuit Breaker uses vacuum as both the insulating and arc-extinguishing medium. Its core contacts are sealed inside a vacuum interrupter. When the moving contact separates from the fixed contact, an electric arc is generated. In a vacuum environment, the arc rapidly disperses and is extinguished as the metal vapor condenses. The arc is naturally extinguished at current zero, and dielectric strength is quickly restored.
Application: VCBs are characterized by high breaking capacity, frequent operation capability, and low maintenance requirements. They are widely used in 3–10kV distribution systems for protection and control of power lines and equipment. They can interrupt both normal load current and short-circuit fault current, providing overload, short-circuit, and under-voltage protection. VCBs can be installed in both withdrawable and fixed-type switchgear.
Application: VCBs are characterized by high breaking capacity, frequent operation capability, and low maintenance requirements. They are widely used in 3–10kV distribution systems for protection and control of power lines and equipment. They can interrupt both normal load current and short-circuit fault current, providing overload, short-circuit, and under-voltage protection. VCBs can be installed in both withdrawable and fixed-type switchgear.
Load Break Switch (LBS)
A Load Break Switch is a switching device located between a disconnector and a circuit breaker. It is equipped with a simple arc-extinguishing mechanism and can make and break normal load current and overload current, but it cannot interrupt short-circuit fault current. After disconnection, a visible isolation gap is usually formed.
Application:LBS is used for switching electrical circuits under normal load conditions. Since it cannot interrupt fault currents, it is usually used together with high-voltage fuses, which provide short-circuit protection. It is widely used in 10kV and below distribution systems for transformer control.
Application:LBS is used for switching electrical circuits under normal load conditions. Since it cannot interrupt fault currents, it is usually used together with high-voltage fuses, which provide short-circuit protection. It is widely used in 10kV and below distribution systems for transformer control.
Disconnector
A disconnector has a simple structure. Its main feature is a clearly visible isolation gap after opening, ensuring that electrical equipment is safely isolated from the power source during maintenance. It has no arc-extinguishing capability and must not be operated under load conditions.
Application:It is mainly used during maintenance or inspection to ensure reliable isolation between equipment and the energized system, providing a clear and visible safety separation point.
Application:It is mainly used during maintenance or inspection to ensure reliable isolation between equipment and the energized system, providing a clear and visible safety separation point.
Switchgear Comparison
| Item | Vacuum Circuit Breaker | Load Break Switch | Disconnector |
|---|---|---|---|
| Arc-Quenching Device | Vacuum interrupter | Simple arc-extinguishing device | No arc-extinguishing capability |
| Making/Breaking Capacity | Can interrupt load and short-circuit currents | Can interrupt load current only | Cannot interrupt load current |
| Primary Purpose | Protection and control | Load switching | Isolation |
| Disconnection Visibility | No visible disconnection | Usually visible disconnection | Clear visible isolation gap |
Operating Mechanism
The operating mechanism is an essential execution unit in Ring Main Unit components, responsible for driving the opening and closing operations of main switches and earthing switches. It converts mechanical, electromagnetic, or stored spring energy into precise mechanical motion to ensure reliable switching performance.
Common Types of Operating Mechanisms
- Spring-Operated Mechanism:Most widely used type, storing energy in a spring for fast and reliable operation.
- Magnetic Mechanism:Simple structure, high reliability, and low maintenance requirements.
- Manual Mechanism:Used as backup or low-cost solution for basic distribution systems.
RMU Unit Types and Operating Mechanisms
| RMU Type | Unit Name | Main Switching Component | Operating Mechanism Type | Description |
|---|---|---|---|---|
| C-Unit | Load Break Switch Unit | Load Break Switch (LBS) | Spring-Operated Mechanism | Single spring operation; optional motorization available |
| F-Unit | LBS-Fuse Combination Unit | LBS + Fuse | Spring Mechanism with Trip Function | Dual spring system; fuse striker trip protection |
| V-Unit | Vacuum Circuit Breaker Unit | Vacuum Circuit Breaker (VCB) | Spring / Magnetic Actuator | Interrupts fault current; works with protection relays |
| D-Unit | Busbar Riser Unit | No main switch | None | Used for busbar connection between sections |
Withdrawable Switchgear vs RMU
| Item | Withdrawable Switchgear (KYN28) | Ring Main Unit (RMU) |
|---|---|---|
| Main Switching Component | Withdrawable Vacuum Circuit Breaker | Load Break Switch + Fuses or fixed VCB |
| Disconnector Function | Replaced by withdrawable truck | Integrated 3-position switch |
| Fuses | Less common | Common for transformer protection |
| Structure | Withdrawable design | Fixed compact design |
| Protection Function | Advanced protection systems | Simpler fuse-based protection |
| Size | Larger | Compact |
