11KV Medium Voltage Ring Main Unit Load Switch

The 11kV Medium Voltage Ring Main Unit Load Switch is the core component in a ring network unit used to control the rated current switch. Cotenele provides highly reliable load switches and ring network unit solutions.

Short-time withstand current: Main circuit short-time withstand current up to 20kA (4s), 25kA (3s); grounding switch short-time withstand current 20kA (4s).

Mechanical life: Load switch 5000 operations, grounding switch 3000 operations.

Standard compliance: GB3804-2017, GB16926-2009, GB/T1985-2023.

Model and meaning

What is a load break switch?

It is a mechanical switching device usually mounted in a ring main unit or gas-insulated siwtchgear, which capable of making, carrying, and breaking electrical currents under normal circuit conditions. Which includes operating under conditions like load currents, no-load conditions, or small inductive currents (such as energizing a transformer).

The load break switch is different with disconnector, It is usually used to handle the electrical stress of interrupting the flow of power when the system is functioning normally. it is equipped with an arc extinguishing system to safely quench the electrical arc generated when the contacts separate under load. Common arc quenching methods include vacuum interruption, SF6 gas immersion, or air compression (puffer type).

Main Functions and Roles Of A Load Break Switch

The most important function of a load break switch is operational control bot not fault protection. Its core functions include:

Switching Load Current:A core function of the load break switch is connecting and disconnecting circuits carrying their normal operating current safely. so that the operators energize or de-energize sections of the power grid, such as transformers or cable rings, for routine maintenance or reconfiguration.

Current Carrying: The load break switch can continuously carry the rated current without overheating when it is closed, ensuring efficient power transmission through the RMU.

Withstanding Faults: A load break switch must be robust enough to withstand the immense electromagnetic and thermal stresses of a fault current flowing through it until an upstream protection device (like a fuse or breaker) clears the fault due to it can not interrupt a short-circuit fault, which is called "fault make" capability.

Providing Isolation: Many load switches are designed to provide a visible or reliable point of isolation, ensuring that downstream equipment is safely disconnected from the power source during maintenance.

Where can this product be used?

11KV Medium Voltage Ring Main Unit Load Switch is the workhorses of Ring Main Units and are used extensively in medium voltage distribution networks (typically up to 24kV or 40.5kV).

Transformer Protection (with Fuses): A load break switch is often combined with medium-voltage fuses in the F-unit ring main unit to protect distribution transformers. The load break switch will handle normal working circuit, while the fuse handle to interrupts any fault current.

Cable Switching: The load break switch creates closed-loop networks through ring in and ring out power cables.

Compatibility with Modern Insulation:

SF6 Insulated RMUs: Load break switches are commonly used in sulfur hexafluoride gas insulated ring main units. SF6 has excellent insulation performance and helps to quench the arc, which has features of compact size and sealed enclosure.

Eco-Friendly RMUs: With the push to reduce SF6 emissions, load switches are now successfully deployed in "green" or environmentally friendly using alternative insulating media such as dry air, nitrogen, or fluoronitrile mixtures. Modern designs optimize the contact structure to ensure reliable arc extinction in these environmentally friendly gases.

Load Break Switch VS Vacuum Circuit Breakers VS Disconnectors

All the load break switch, vacuum circuit breaker and disconnector are core components for the RMU and eco-friendly switchgear and gas-insulated switchgear,but there lots of difference between these three components for their functions and structures:

The 11KV Medium Voltage Ring Main Unit Load Switch is the primary device for the routine control of power flow within a Ring Main Unit. It offers the critical ability to safely manage live circuits while maintaining a compact form factor suitable for modern, sealed enclosures, whether they utilize traditional SF6 gas or new environmentally friendly alternatives. Its function is distinct from the purely safety-oriented disconnector and the protective circuit breaker.

Technical Parameters

Appearance and Dimension

FAQ

Q1:What is an 11kV Medium Voltage Ring Main Unit Load Switch?

A: An 11kV medium voltage ring main unit load switch is a mechanical switching device installed in a ring main unit (RMU), gas-insulated switchgear (GIS), or environmentally friendly switchgear. It is used to safely connect and disconnect medium voltage current. It can carry the rated load current and disconnect the circuit under normal operating conditions, but it is not suitable for directly interrupting large short-circuit currents.

Q2:What is the difference between a ring main unit and a metal -clad switchgear? How should we choose between them?

A: The main difference is for the structure and scope of application.
Ring main unit: compact structure and small size, and the main internal components usually use a combination of load break switches and fuses. Mainly used at the end of the distribution network (such as residential distribution, small substations), responsible for transformer control and protection, with a focus on ring network power supply and cable tapping.
Metal-cladswitchgear: It has a large volume and is usually equipped with circuit breakers, which have extremely high breaking capacity. Mainly used for substation main circuits or large industrial loads, responsible for large capacity power distribution and short-circuit protection.
Selection suggestion: For transformers with a capacity of 1250 kVA or less, or in situations where space is limited and a ring network power supply is required, you can use the ring main unit. For high-capacity incoming lines or critical equipment, Metal-cladswitchgear is more suitable..

Q3:Is SF6 an unfriendly gas for environment? Are there environmentally friendly alternatives now?

A: Yes, SF6 is one of the most potent greenhouse gases known. To meet environmental requirements, mature environmentally friendly gas-insulated ring main unit products are now available on the market.
• Alternatives: The ring main units which adopt dry air, nitrogen, or eco-friendly gas mixtures as the insulating medium.
• Performance: These eco-friendly ring main units are very close to SF6-insulated RMUs for compactness and reliability, and they are helpful for environmentally protection significantly. If you hope to get green certification or environmental, you can choose the eco-friendly RMUs.

Q4:Which component is better mounted inside the Ring Main Unit?A load switch and fuse combination or a circuit breaker?

A: Both of them are ok, only their functions are different.
Load Switch-Fuse Combination: Designed for transformer protection. Fuses offer high current-limiting capability, fast operation, and lower cost. The disadvantage is the need to replace the fuse element after operation.
Circuit Breaker: Used for high-capacity incoming/outgoing lines or applications demanding very high supply continuity. It can be reclosed after a fault trip without replacing parts, but the cost is higher.
Conclusion: The combination unit is typically chosen for transformer protection; circuit breakers are chosen for main line incoming/outgoing feeders.

Quality Warranty And After-sale Service

1.We provide remote online video guidance and complimentary specialized technical training for our customers' technical personnel. Within one year following the product's commissioning, we offer free maintenance services. Thereafter, paid maintenance services remain available for customers who wish to continue receiving support.

2.We are committed to delivering long-term, enthusiastic, and thoughtful service. Upon receiving a customer request, we will respond via email or telephone within one hour, ensuring timely communication and efficient handling.

3.We establish a permanent technical consultation channel for our customers. We are always willing to provide professional support and solutions for any issues related to product usage or technical difficulties encountered during system operation.

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