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In medium-voltage power distribution systems, medium-voltage switchgear is the core of ensuring the safe and efficient operation of power, and it undertakes the functions of circuit control, protection, and isolation. Among the core components of the medium-voltage switchgear, the SF6 circuit breaker and the Chave seccionadora de carga SF6 is widely used due to the excellent insulation and arc extinguishing properties of SF6 gas, but there are significant differences in the functional positioning and applicable scenarios of the two.
This article will clarify the core differences between the two devices to help you make the right choice based on your own power system requirements.
SF6 circuit breaker and SF6 load switch Although the SF6 load break switch uses SF6 gas as the insulating and arc extinguishing medium, there are obvious differences in switch capacity, protection function, and structural design. The following is a detailed comparison from five core dimensions:
The core difference of switch capacity lies in whether it can cut off fault current. The SF6 circuit breaker is specially designed to handle both normal load current and huge fault current (such as short-circuit current). Its rated breaking current can reach tens of thousands of amperes, and it can achieve rapid and reliable breaking even in severe fault scenarios.
And the Chave seccionadora de carga SF6 is mainly used to switch on and off the normal load current, such as switching on or off the power supply of the distribution line and transformer in the normal operation state of the system. Its ability to cut fault currents is limited, and it can only deal with small overload currents for a short time. Taking the FLN36-14D SF6 load switch as an example, it is optimized for normal load switching, and the rated load breaking current can meet the needs of general distribution scenarios.
The SF6 circuit breaker has independent and complete protection functions. It can quickly detect fault signals such as overcurrent, short circuit, and overvoltage through the corresponding relay protection device, and immediately trip and cut off the circuit to prevent the fault from expanding, protect the power grid and equipment safety, and is a “protective switch” in the power system.
O SF6 load break switch has no independent fault protection ability, and its core function is “control” rather than “protection”. When there is a fault in the circuit, it is necessary to rely on the protective device (such as fuses or backup circuit breakers) to cut off the fault current, and it cannot respond and handle the fault situation independently.
Although both use SF6 gas as the arc extinguishing medium, the arc extinguishing mechanism is significantly different due to different functional requirements. The arc extinguishing system of SF6 circuit breaker is complex and precise, and usually adopts compressed air type, The self-energizing type and other arc extinguishing methods can produce strong SF6 gas flow in a very short time (usually a few milliseconds), quickly cool and extinguish the arc, and easily deal with high-energy arcs generated by fault currents.
The arc extinguishing mechanism is relatively simple, mainly using the natural expansion of SF6 gas or the arc extinguishing effect of the contact structure, which is only suitable for extinguishing low-energy arcs generated when normal loads are switched on and off, and cannot deal with high-temperature and high-energy arcs generated by fault currents.
The SF6 circuit breaker, which needs to meet the requirements of high breaking capacity and protection function, has a complex structure, including a precise arc extinguishing chamber, operating mechanism, and auxiliary protection system. The manufacturing process is strict, the material requirements are high, and the overall cost is relatively high.
O SF6 load break switch has a simple structure, no complicated arc extinguishing chamber and protection system, and the operating mechanism is also simpler. For example, the outdoor SF6 load switch FLW34-10/24/41.5 of Chuanli adopts an integrated modular design, is small in size and low in cost, and has a higher cost-performance ratio than SF6 circuit breakers in scenarios where only load switching is required.
SF6 circuit breakers are mainly used in scenarios that require strict fault protection, such as the incoming and outgoing lines of medium-voltage substations, the power supply lines of large industrial enterprises, and the connection points of new energy systems, and are suitable for situations where fault currents may frequently occur and high reliability of power supply is required.
Chave seccionadora de carga SF6 is widely used in scenarios where only normal load switching is required, such as urban power distribution networks, residential community power distribution lines, ring network cabinets (RMU), and the primary side of power distribution transformers. The SF6 load switch products of Chuanli have been widely used in the transformation of urban and rural distribution networks due to their high cost performance and operational reliability.
In the following scenarios, choose the Chave seccionadora de carga SF6 is the most cost-effective solution:
Only normal load switching is required: The core requirement is to turn on or turn off the normal load current, such as controlling the power supply of residential communities, small commercial outlets, or distribution transformers.
Simple protection configuration: The circuit is equipped with independent protection devices (such as fuses), and the switch only needs to perform control functions.
Limited space and cost: The installation space is tight (such as indoor ring network cabinet) and the project budget is limited, requiring economical and compact switching equipment.
Outdoor distribution scenario: Outdoor distribution lines with relatively stable load and low fault probability, such as rural network and suburban road lighting power supply, the FLW34 series outdoor SF6 load switch of Chuanli is an ideal choice for such scenarios.
In the following scenarios, a SF6 circuit breaker must be selected to ensure the safe and stable operation of the power system:
Fault current needs to be handled: The circuit may generate a large fault current (such as short-circuit current), and the switch needs to quickly cut off the fault to avoid equipment damage and grid paralysis.
Need independent protection function: The scene requires the switch to have independent fault detection and trip function, such as the main control switch of the medium voltage substation and the power supply line of the key industrial equipment.
High reliability of power supply: In situations where continuous power supply is strictly required, such as hospitals, data centers, and large industrial production lines, the speed of fault handling directly affects production operations.
Large-capacity power supply scenarios: large-scale industrial and mining enterprises, new energy power plants and other high-power load scenarios require switches with high-voltage breaking capability to match load characteristics.
SF6 circuit breaker (SF6 circuit breaker) and SF6 load switch ( The choice of SF6 load break switch needs to be comprehensively evaluated based on the actual needs of the power system. Combining with the professional experience of Chuanli, the following four-step selection method is proposed:
Clarify the type of current: First, confirm whether the switch needs to handle fault current. If it only involves normal load current, the SF6 load switch can meet the requirements; If fault current may occur, SF6 circuit breaker must be selected.
Define the functional requirements: Determine whether the switch needs independent protection function, if the system has no other protection device, it is necessary to choose SF6 circuit breaker with integrated protection capability; If there are matching fuses or relays, SF6 load switches can be considered.
Evaluate the scene conditions: Consider factors such as installation environment (indoor/outdoor), space size, budget constraints, etc. The SF6 load switch from Chuanli is more suitable for outdoor, compact scenes and limited budgets; SF6 circuit breakers should be preferred for core power supply points with high reliability requirements.
Refer to the manufacturer’s suggestion: Communicate with professional manufacturers such as Chuanli to provide parameters such as system voltage, rated current, fault current level, and obtain personalized selection suggestions based on product performance and application cases.
Chuanli has been deeply engaged in the research and production of medium voltage switchgear for many years. Its SF6 circuit breaker and SF6 load switch The SF6 Load Break Switch) product has won wide recognition in the market due to its professional advantages:
Complete product series: Covering indoor and outdoor SF6 load switches (such as FLN36-10D, FLW34 series) and various types of SF6 circuit breakers, meeting the needs of 12kV, 24kV, 40.5kV and other medium voltage levels, providing one-stop procurement solutions.
Excellent product performance: All SF6 switch devices use high-purity SF6 gas as the insulating and arc-quenching medium. The gas leakage rate is low. The switching performance of the load switch is stable, the breaking capacity of the circuit breaker is outstanding, and it fully complies with national and industry standards.
Strong environmental adaptability: The product adopts waterproof, dustproof, anti-corrosion, anti-aging design. The outdoor series can operate stably in harsh environments such as -40 ℃ to 60 ℃, high humidity, strong sand and wind, and is suitable for different regional needs.
Intelligent configuration is optional: It can be equipped with an intelligent monitoring module to realize real-time monitoring of SF6 gas density, switch status, and operating parameters, and support remote control to improve operation and maintenance efficiency.
Reliable after-sales support: Provide pre-sales technical consulting, in-sales installation guidance, and after-sales maintenance services. Professional teams respond quickly to ensure the safe and stable operation of the equipment throughout its life cycle.
SF6 circuit breaker and SF6 load break switch is also an important part of medium voltage switchgear, but the two have clear functional boundaries and application scenarios. The core of selection lies in clarifying the actual needs of the power system: if fault protection and high-open-break capability are required, SF6 circuit breaker is the inevitable choice; If only normal load switching is required and cost control is considered, the SF6 load switch is more economical and practical.
As a professional SF6 switchgear manufacturer, Chuanli provides reliable product support for various scenarios with its high-quality SF6 circuit breaker and SF6 load switch products (such as FLN36-10D, FLW34 series). Choosing suitable SF6 switchgear and cooperating with trusted manufacturers such as Chuanli is of great significance to improving the reliability of the power system, reducing operation and maintenance costs, and ensuring safe power supply.
Q1: Can an SF6 load break switch interrupt fault current?
A1: No. It can only switch on and off the normal load current, and the fault current needs to be cut off by the corresponding fuse or circuit breaker.
Q2: What is the service life of SF6 switchgear?
A2: The service life of Chuanli products is 15-20 years. Regular SF6 gas detection and maintenance can extend the service life.
Q3: Is SF6 safe for use and handling?
A3: Safety. Chuanli switch equipment adopts sealed structure to prevent leakage, and can be operated safely by following standard operating procedures.
Q4: Do I need a relay protection system with an SF6 circuit breaker?
A4: Need. It relies on the relay protection system to detect faults and trigger tripping to ensure that faults are handled in a timely manner.
Q5: Can an SF6 load break switch be used in ring main units?
A5: Absolutely. The FLN36-10D series is widely used in indoor ring network cabinets to realize load switching and line isolation.
