Indoor Load Break Switch

The Usune FLN36-40.5 Indoor Load Break Switch is a core high-voltage electrical component independently developed and manufactured by Zhejiang Usune Electric. It is specifically designed for the safe and efficient power distribution needs of 35kV rated voltage scenarios and is a key piece of equipment in modern power distribution systems, especially suitable for ring network and dual-radial power supply systems, playing a vital role in ensuring stable and safe power transmission and distribution. This product can independently switch on and off load currents and overload currents, or it can be combined in series with a current-limiting fuse to replace a circuit breaker. The load switch handles the switching of various load currents, while the current-limiting fuse handles the breaking of heavy overload currents and short-circuit currents, achieving multi-level protection for the power system. Its compact structure, easy installation, and maintenance-free operation make it an ideal product for urban power grid upgrades and industrial power distribution optimization.

Product Features

1. Structural Advantages

The Indoor Load Break Switch adopts a double-break, three-position, rotating moving contact structure, equipped with a three-position arc-extinguishing chamber (open-close-ground), ensuring smooth switching under different operating conditions and improving system stability. The overall three-phase installation design offers good synchronization, fewer components, and convenient commissioning and installation, reducing the difficulty of on-site construction and maintenance.

2. Insulation Performance

The switch uses an upper and lower epoxy resin cast shell for sealed assembly. The main circuit and grounding circuit system are all housed within the shell, effectively isolating the external environment and preventing dust and moisture corrosion. The high insulation strength of the break points and the large creepage distance, along with the voltage-equalizing shielding at the outgoing terminals, further enhance insulation reliability and meet the stringent requirements of high-voltage power distribution systems.

3. Safety Performance

Excellent safety performance. In the event of an internal arcing fault, the weak rear structure of the outer casing will rupture, and the pressure relief valve on the top of the cabinet will open, expelling the overpressure airflow outside the cabinet, preventing equipment damage and personal safety hazards. Equipped with a five-proof interlock function, it fundamentally eliminates misoperation, ensuring the safety of operators and equipment.

4. Ease of Operation

The Indoor Load Break Switch supports both manual and electric operation modes, flexibly adapting to site requirements, offering convenience and reliability. It adopts a maintenance-free design, with a long electrical and mechanical lifespan, reducing later maintenance costs. The switchgear is constructed entirely of aluminum-zinc plate, offering corrosion resistance and high mechanical strength, suitable for various indoor working conditions.

Technical Advantages

1. High Insulation Safety: Employing a primary high-voltage insulation design with high margin and an IP33 protection rating, it enhances the insulation safety level of the front operating compartment, effectively protecting the personal safety of operators.

2. Wide Applicability: Suitable for compact, miniaturized, and frequently operated scenarios, widely used in urban power grids, industrial and commercial power distribution, and new energy grid connection, meeting diverse needs in different scenarios.

3. Integrated Design: Compact combination switch design, integrating isolating switch and grounding functions, reducing equipment space occupation and facilitating power distribution system integration.

4. High Reliability: Employs a high-reliability SF6 load switch. SF6 gas pressure is low, operation is reliable, and the gas retention life can reach 20 years, eliminating the need for frequent gas replenishment and ensuring long-term stable operation.

Technical Parameters

Arc Extinguishing Principle

This indoor load break switch uses SF6 gas as the arc extinguishing medium, which has excellent arc extinguishing and insulation performance. When the switch breaks current, an arc is generated instantaneously upon separation of the moving and stationary contacts. Driven by the magnetic field of the permanent magnet, the arc moves rapidly and is elongated, while being continuously ionized and cooled by the SF6 gas, ultimately extinguishing when the current crosses zero, achieving safe and rapid current interruption.

Double break point distance provides high isolation and breaking insulation levels. Utilizing the permanent magnet rotating arc principle, it features low operating energy consumption, strong arc extinguishing capability, and minimal contact wear, effectively extending the electrical life of the switch.

Usage Conditions

To ensure stable product operation, the following conditions must be met for installation and use:
1. Altitude: Not exceeding 1000 meters (special requirements must be specified when ordering);
2. Ambient Temperature: -25℃～+40℃;
3. Relative Humidity: Daily average ≤95%, monthly average ≤90%;
4. Seismic Intensity: Not exceeding Class B;
5. Ambient air free from severe pollution such as dust, smoke, chemical corrosives, flammable gases, gasoline, and salt spray.

Project Reference

Cas-space Rocket Launch Project

Test Report

Practical Application Case

As a professional manufacturer of high-voltage electrical equipment in China, Yu Shun Electric provided FLN36-40.5 Indoor Load Break Switches for a large-scale urban power grid upgrade project in East China. The project involved 35kV distribution lines in eight urban areas, covering residential areas, commercial centers, and industrial parks, with extremely high requirements for power supply stability and safety.

Before the upgrade, the existing switchgear suffered from poor insulation, frequent maintenance, and low safety, failing to meet the needs of the urban power grid development. After selecting this product, the project achieved three major improvements: First, the five-proof interlocking and arc-extinguishing design reduces misoperation and arc faults, improving system safety; second, the maintenance-free design reduces monthly maintenance time by 80%, lowering operation and maintenance costs; and third, the compact structure adapts to the indoor installation space of urban substations, facilitating power distribution system integration. The product has experienced zero failures in over two years of operation, ensuring stable power supply for over 500,000 residents and over 300 businesses, earning high recognition from the project owner and local power supply department. Usune Electric, as the supplier, provided comprehensive after-sales services including on-site installation guidance and technical training.

FAQ

Q1: What is the service life of the Usune FLN36-40.5 indoor load switch, and is regular maintenance required?

A1: The product adopts a maintenance-free design with a long electrical and mechanical lifespan. The SF6 gas retention life can reach 20 years. Under normal use conditions, no regular maintenance is required; only periodic checks of the equipment casing, operating mechanism, and gas pressure (if necessary) are needed. All Usune products undergo rigorous quality testing before leaving the factory to ensure product lifespan and reliability.

Q2: What are the differences between this Indoor Load Break Switch and a traditional circuit breaker, and in which scenarios can it replace a circuit breaker?

A2: The core difference is that load break switches are mainly used to switch on and off load currents and overload currents, while traditional circuit breakers can additionally interrupt short-circuit currents. This product, combined with a current-limiting fuse in series, can replace a circuit breaker: the load break switch is responsible for switching on and off various load currents, while the current-limiting fuse handles heavy overload and short-circuit current interruption. It is suitable for 35kV ring networks and dual-radial power supply systems (such as urban power grid branches, industrial and commercial distribution rooms, etc.), reducing equipment costs while ensuring system safety. As a professional manufacturer in China, Yushun Electric can provide professional technical guidance to assist customers in selecting suitable solutions.