SF6 Load Switch Breaker

TOONICE’s the full name of SF6 load switch is SF6 Gas-Insulated Load Switch. It is a core “electrical energy control device” in medium-voltage power distribution systems (usually used in 10kV, 20kV, and 35kV voltage levels). Its core function is to connect and disconnect the load current under normal operating conditions (e.g., the rated current of power lines, transformers, and motors). At the same time, it relies on SF6 gas to achieve the dual functions of “insulation” and “arc extinction”.

Positioned between “disconnectors” (only capable of disconnecting no-load current) and “circuit breakers” (capable of disconnecting short-circuit current), it has the advantages of “low cost, compact size, and easy maintenance” and is widely used in scenarios such as branch circuits and user terminals of medium-voltage distribution networks.

I.Core Features

1. High-efficiency Insulation and Arc Extinction, Safe without Open Flame:

① Insulation performance: The insulation strength of SF₆ gas is 3-5 times that of air. It can achieve reliable insulation for medium-voltage circuits in narrow gas chambers and avoid the problem that air-insulated equipment is easily affected by humidity and dust.

② Arc-extinguishing capability: SF₆ gas has “electronegativity” (can adsorb free electrons generated by electric arcs), and the arc-extinguishing speed is extremely fast (arc-extinguishing time ≤ 0.01 seconds). Moreover, there is no open flame or flying arc during the arc-extinguishing process. Even in a closed gas chamber, it will not cause fire risks, and its safety far surpasses that of traditional air-type or oil-immersed load switches.

2. Compact Size, Saving Installation Space:

Due to the high insulation density of SF₆ gas, the equipment does not require a huge air insulation gap. The overall volume is only 1/2 – 2/3 of that of air-type load switches with the same capacity. For example, a 10kV/630A SF₆ load switch can reduce the cabinet width to 400 – 600mm, which is suitable for scenarios with limited space such as substations and power distribution rooms, and is especially suitable for modular prefabricated cabins (such as photovoltaic prefabricated cabins, distribution station prefabricated cabins).

3. Strong Environmental Adaptability and Long Maintenance-free Period

① Moisture-proof and dust-proof: The equipment adopts a sealed gas chamber (welded or bolted seal, equipped with a gas density relay), which can effectively isolate external moisture, dust, and corrosive gases. It can operate stably in harsh environments (such as coastal salt spray areas, industrial dust areas) with a temperature range of -30°C to 60°C and a relative humidity ≤ 95%.

② Maintenance-free: The leakage rate of SF₆ gas is extremely low (annual leakage rate ≤ 0.5%). Under normal circumstances, there is no need to replenish the gas, and the maintenance-free period can reach 10-15 years, greatly reducing operation and maintenance costs (traditional oil-immersed equipment needs oil replacement every 3-5 years).

4. Convenient Operation, Adaptable to Multiple Control Modes

It supports two modes: “manual operation” and “electric operation”:

① Manual operation: Opening and closing are realized through a handle, suitable for no-power or emergency scenarios.

② Electric operation: Equipped with a motor operating mechanism, it can realize opening and closing through remote control signals (such as SCADA system, PLC instructions) to meet the requirements of intelligent power distribution, and the operation life can reach more than 10,000 times (mechanical life).

II. Technical characteristics

III. Structural Composition

The structure of KYN28 switchgear is designed around “safety isolation and functional zoning”, with various components working together to achieve power control and protection. The specific composition is as follows:

IV. Typical Application Scenarios:

1. Branch Circuits of Urban 10kV Distribution Network

In urban distribution networks, circuit breakers are used for main circuits (to interrupt short-circuit currents), while a combination of SF6 load switches + fuses is adopted for branch circuits (such as power supply circuits for residential communities and shops) — which not only meets the demand for “interrupting load currents on the user side” but also reduces equipment costs (the price of an SF6 load switch is only 1/3 – 1/2 of that of a circuit breaker with the same capacity).

2. Grid-Connection Cabinets for Distributed Photovoltaic/Wind Power

In the grid-connection cabinets of distributed photovoltaic power stations (10kV grid connection), SF6 load switches are used for “normal grid connection / disconnection” (connecting / interrupting the generation current of photovoltaic arrays). Matched with fuses to protect grid-connection lines from short-circuit faults, they are also suitable for installation in prefabricated cabins due to their small size and maintenance-free feature.

3. High-Voltage Load Control in Industrial Workshops

For high-voltage motors in factories (such as 10kV water pumps, fans) and high-voltage transformers (such as 10kV/0.4kV transformers in workshops), if there is no need to frequently interrupt short-circuit currents (short-circuit protection is undertaken by upper-level circuit breakers), SF6 load switches can be used for control — they are easy to operate and have low maintenance costs, making them suitable for non-continuous production working conditions.

4. Outdoor Pole-Mounted Power Distribution Equipment

Outdoor-type SF6 load switches (such as pole-mounted SF6 load switches) can be directly installed on electric poles and are used for branch control of rural distribution networks and suburban lines. With an IP54 protection class, they can resist wind, rain, and dust, and their maintenance-free feature reduces the workload of outdoor inspections.