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High Quality Ring Main Unit Components for Reliable Power Distribution
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11KV Ring Main Unit Circuit Breaker Isolator Switch
Cotenele company is a professional manufacturer for the core components of a medium voltage switchgear and ring main units. The KDV-12D/1250-25 series 11KV Ring Main Unit Circuit Breaker Isolator Switch manufactured by Contenele, have lots of features such as ease of installation, low maintenance requirements, extended service life, compact dimensions, cost-effectiveness, and high operational reliability. The main circuit meet the requirements of which short-time withstand current is 20kA for 4 seconds and 25kA for 3 seconds. The vacuum circuit breaker mechanical operations are up to 10,000 mechanical operations, and the disconnector integrated with the vacuum circuit breaker is rated for 3,000 mechanical operations.
11KV RMU Electrical Circuit Breaker Disconnector Operating Mechanism
Cotenele company is a supplier for the core components of medium-voltage RMU from China,our KDVM-12/1250-20 series 11KV RMU Electrical Circuit Breaker Disconnector Operating Mechanism are the core components within medium-voltage Ring Main Units (RMUs). These circuit breaker and disconector operating mechanisms support auto-reclosing, The combination of the circuit breaker operating menchanism and disconnector operating mechanism provide secure mechanical interlocking, ensuring high reliability and a substantial mechanical endurance exceeding 10,000 cycles. Both of these two operating mechanisms meet the national standards, including GB1984-2014 for high-voltage AC circuit breakers and GB/T1985-2023 for high-voltage AC disconnectors and earthing switches.
11KV Ring Main Unit Vacuum Circuit Breaker Disconnector
Cotenele is a professional manufacturer of components for gas-insulated Ring Main Units (RMUs) and environmentally friendly switchgear in modern medium-voltage distribution grid,our products rated voltage is from 12kV to 40.5kV. The KDV-12D/630-20-S series 11KV Ring Main Unit Vacuum Circuit Breaker Disconnector features for easy installation, minimal maintenance requirements, long service life, compact dimensions, and cost-effectiveness while ensuring safe and reliable operation. All of components which we manufactured fully complies with the national standard such as GB1984-2014 for high-voltage AC circuit breakers and GB/T1985-2023 for high-voltage AC disconnectors and earthing switches.
11KV Medium Voltage Circuit Breaker Isolator Mechanism
Cotenele is one of the core partners of State Grid Corporation of China,our products such as medium-voltage ring main units and environmentally friendly switchgears is widely popular in their medium voltage power distribution projects.The KDVM-12/630-20-S series 11KV Medium Voltage Circuit Breaker Isolator Mechanism manufactured by Cotenele is a matching equipment suitable for the closing and opening operations of circuit breakers in rechargeable medium-voltage ring main units.This product complies with the requirements of relevant standards and specifications such as GB1984-2014 "High Voltage AC Circuit Breakers" and GB/T1985-2023 "High Voltage AC Disconnectors and Grounding Switches".
11KV Medium Voltage Ring Main Unit Load Switch
Contenele is a core manufacturer for RMUs and their components in China.The KDK-12D/630-20 series 11KV Medium Voltage Ring Main Unit Load Switch is one of main products by our company.This load break switch is used in RMU such as medium-voltage gas-insulated switchgear and Environmentally-friendly switchgear.it complies with the national standard such as GB3804-2017 "3.6kV~40.5kV High Voltage AC Load Switches", GB16926-2009 "AC High Voltage Load Switches - One Fuse Combination Apparatus", and GB/T1985-2023 "High Voltage AC Isolation Switches and Grounding Switches".
11KV Load Break Switch for Medium Voltage Ring Main Unit
The KDK-12D/800-20 series 11KV Load Break Switch For Medium Voltage Ring Main Unit are important products of Cotenele company,these load break switch complies with the requirements of relevant standards and specifications such as GB3804-2017 "3.6kV~40.5kV High Voltage AC Load Switches", GB16926-2009 "AC High Voltage Load Switches - One Fuse Combination Apparatus", and GB/T1985-2023 "High Voltage AC Isolation Switches and Grounding Switches". The main circuit's short-term withstand current should meet 20kA (4s) and 25kA (3s), and the mechanical life of the load switch should be 5000 times. The short-term withstand current of the grounding switch meets 20kA (4s), and the mechanical life is 3000 times.
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 |
