Gas-Insulated Switchgear

What is A Gas-Insulated Switchgear

In power equipment, the “SF6 gas-insulated switchgear” plays a key role in high-voltage distribution. Simply put, this is a composite device – it integrates core components such as circuit breakers, busbars, and transformers, as well as grounding switches and surge protectors, all into a sturdy metal frame. Immersed in the inert gas SF6.

SF6 itself is quite special. As an inert gas, it has extremely stable chemical properties and is not prone to decomposition even at high temperatures. Its insulation capacity far exceeds that of air, and it can also efficiently extinguish arcs. For you, this layer of “gas armor” is precisely why it is so popular. Next, let’s talk in detail about how to make a choice that better suits your taste.

What are the Components of A Gas Insulated Switchgear

Coaxial Busbar

Unlike ordinary busbars, it is designed on the same axis. The central conductor is covered with an outer shielding layer, ensuring a uniform electric field distribution and strong anti-interference ability. No matter how compact the equipment is, this busbar can flexibly connect each module and has low transmission loss.

Spring-Type Insertion Connector

This is the “joint” of the module. You don’t need to tighten the screws.When you disassemble and assemble the module, just insert and pull it in gently. It’s much faster than the traditional bolt connection, especially saving time during maintenance. The contact surface has undergone special treatment, making it less prone to oxidation and having a long service life.

Composite Insulating Material

Commonly used are alumina particles mixed with epoxy resin or modified engineering plastics. It has a high density and is resistant to electrical marks. Even if it is immersed in SF6 gas for a long time, it will not age. Those precise components, preventing partial discharge and ensuring the safety of equipment, all depend on it.

Disconnector + Circuit Breaker Combination

These two are “safety partners”. Before maintenance, disconnect the load first and then close the disconnector to completely isolate the power supply. The two are designed in series, with a clear operation sequence. As long as you follow the procedures, you won’t accidentally touch them, and the safety factor is maximized.

Grounding Switch

When the equipment is under maintenance, you need to force the grounding of the circuits. In case there is any residual charge or induced electricity, it will be directly conducted into the earth. Some models are equipped with a quick grounding function, which will automatically act in case of a fault to protect personnel and equipment. 

Observation Window

The gas isolation switch GIS is fully sealed, making the internal state invisible, and thus it comes in handy. It is made of transparent high-voltage resistant material, allowing direct observation of the contact position and whether there are any discharge marks. When you conduct your daily inspections, just take a quick look. You can spot any problems early without having to disassemble the equipment and cause trouble.

Independent Gas Compartment

SF6 gas is the core of GIS electrical insulation, and each key component is isolated in a separate compartment. Such a leak at one point does not affect others, and the air can be extracted quickly during maintenance. We are equipped with an artificial intelligence system. You can conveniently keep track of the gas status at any time, and there is a basis for replenishment or replacement.

Local Control Cabinet

You can operate the opening and closing of the switch on site and also connect to the background monitoring. In an emergency, it stops immediately upon pressing the emergency stop button. The safety factor is very high.

Gas Insulated Switchgear Working Principle

Sealed Metal Casing

The SF6 switchgear has all its core components encapsulated in a sturdy metal tank. It completely isolates the internal high-pressure environment from the outside. The metal tank provides the first physical barrier.

SF6 Gas Filling Creates an Insulating Environment

This gas itself has extremely strong electronegativity, meaning it can capture free electrons very efficiently. When current passes through, these electrons will be rapidly adsorbed by SF6 molecules, forming a stable negative ionic structure. This greatly hinders the flow path of current, thereby achieving excellent insulation performance. For you, this means that in a relatively compact space, it can withstand very high voltages without breakdown.

Contact and Disconnection of The Moving Contact

Connecting or disconnecting a circuit is accomplished by the internal moving contacts and static contacts. When you issue an operation command, the operating mechanism will drive the moving contact to move, achieving contact (closing) or separation (opening) with the static contact.

Arc Generation and Gas Arc Extinguishing Mechanism

When the moving contact points touch, an arc is generated. At this point, the temperature in the arc area immersed in SF6 gas rises sharply. High temperatures cause the decomposition of SF6 gas molecules. Decomposition products absorb the energy of the electric arc.

SF6 gas itself also has the function of adsorbing electrons. So together, the electron current after zero is too small to ignite.

The Gas Pressure Maintenance 

SF6 gas’s insulation and arc-extinguishing performance reach their optimal state within the range of 0.3 to 0.6 megapascals. The system will ensure that the gas pressure is maintained within the set working range. The pressure drops, which means that the gas is likely to leak out. Then the console will immediately receive the information.

The Operating Mechanism Provides Power

Whether you operate manually or electrically, ultimately, a reliable operating mechanism is needed to drive the contact movement. It receives your operation command, transmits the force to the moving contact, and ensures that the opening and closing actions are fast, accurate, and in place.

What is the Function of Gas Insulated Switchgear

Flexibly Switch Circuit States

You need it to be able to quickly connect or disconnect circuits during normal operation, like shifting gears for the power grid. Whether it is routine maintenance or temporary power supply adjustment, it can operate precisely and reduce the power outage time. If the situation is urgent. For instance overload of a certain section of the line can immediately cut off the faulty circuit to ensure that other areas are not affected.

Safely Separate the Faulty Area

It can quickly separate the faulty part from the normal power grid to prevent the problem from escalating. For instance, if there is a short circuit in a certain line, it can recognize it immediately to prevent the transformer or other equipment from being affected, thus ensuring the safety of the entire system.

Smoothly Switch the Operation Mode

From single busbar operation to double busbar operation, or switching back from maintenance state to live state. It can complete these adjustments without power outages or with minimal power outages.

Accurately Measure Electrical Energy Parameters

Its built-in metering module will  Surveillance current, voltage, and power in real time. You can keep track of the power consumption of each line at any time, detect abnormal loads or losses. Only when the data is accurate can you manage it with peace of mind.

Allocate the Current Reasonably

It distributes power to different branches according to demand, such as giving priority to ensuring important loads. Make sure the distribution is balanced and reasonable. In combination with protective devices, it can make the flow of electrical energy more efficient and reduce waste.

The Advantages of Gas Isolation Switchgear

High Space Utilization

The structure is highly integrated. Under the same voltage level, its volume is reduced by more than 60% compared with traditional equipment. The compact layout releases valuable site resources, making it particularly suitable for urban substations and space-constrained scenarios. The modular assembly solution makes later expansion more flexible.

Multiple Safety Protections

The fully enclosed stainless steel shell forms a physical barrier, completely isolating the risk of arc leakage. SF6 gas itself has excellent arc-extinguishing capabilities. When combined with a pressure monitoring system, it can eliminate the risk of explosion at the root. Your staff only need to operate the external mechanism to complete the maintenance.

Eco-Friendly Protection Mechanism

The sealed air chamber completely blocks the risk of oil leakage, ensuring zero emissions during operation. We also have specially designed bird-proof structures, ensuring that you won’t be disturbed by flying birds outdoors. It can be said that in the outdoors, gas-insulated Switchgear stand out from the rest.

All-Climate Combat Capability

It operates stably within a wide temperature range of -10℃ to +40℃, and has a protection level of IP67 in environments with heavy rain, salt spray, and sand and dust. The UV-enhanced shell resists aging, eliminating the need for additional dehumidification devices in high-humidity areas and significantly reducing environmental adaptation costs.

Intelligent Electromagnetic Compatibility Design

The internal key components adopt layered shielding technology. You don’t need to worry about being disturbed by other radiation.

Silent Operation Model

There is no mechanical contact bouncing noise, and the operating sound pressure is lower than 55dB (equivalent to the volume of an indoor conversation). Urban substations can be deployed close to residential areas, ensuring no disturbance to residents during night operations and improving the working environment for operation and maintenance personnel.

Low Long-Term Cost

The oil-free maintenance design eliminates the cost of oil procurement. The micro-water online monitoring function warns of gas deterioration, avoiding sudden shutdown losses and reducing the overall operation and maintenance cost by 40%.

Seamless Support for Multiple Busbar Systems

Through standardized interface adapters, single busbars, double busbars, ring busbars, and other topological structures can be quickly connected. Supports hot-swappable connection modules. During the renovation period, it will not affect the power supply of other circuits, ensuring business continuity.

Breakthrough in Mechanical Stability

The pressurized air tank has been optimized through finite element analysis, and its seismic intensity has reached 8 degrees. Even in extreme weather conditions, the operating mechanism still maintains precise positioning, eliminating the risk of misoperation.

Simple Maintenance

The modular components enable “drawer-style” replacement, and the disassembly and assembly of the circuit breaker unit can be completed with ordinary tools. The visual observation window displays the air pressure status in real time. Combined with a portable leak detector, a single person can complete a routine inspection in 30 minutes.

Extremely Long Service Life

Accelerated aging tests confirmed that the core components have a lifespan of over 30 years. The German TUV certification case shows that it can operate continuously for up to 280,000 hours without failure, significantly shortening the investment payback period.

Intrinsically Safe Arc Extinguishing Technology

The extremely strong electronegativity of SF6 molecules can instantaneously capture free electrons to form negative ions, causing a sudden drop in the plasma density of the arc channel. The measured breaking time is less than 30ms, which is three times faster than that of an air switch. The speed of fault removal determines the efficiency of power grid recovery.

It is small in size. Strong resistance to pollution. Thanks to these advantages, GIS substations are often used in environments with limited space, as well as extremely harsh and highly polluted conditions. Here are some common application scenarios of GIS. Come and see if your industry is included.

Urban and Industrial-Intensive Areas

Look at those old urban area expansions, rooftop power stations, or industrial parks. The SF6 gas-insulated switchgear is small in size and can be stuffed into a narrow distribution room, saving you a lot of space.

In addition, the SF6 switchgear is well sealed and is not afraid of dirt or short circuits. It is especially suitable for your needs who want to efficiently set up points in a busy downtown area.

Special Geographical Environment

Valleys, mountainous areas, offshore platforms, or the vicinity of hydropower stations are either damp and foggy or have heavy salt fog and large temperature differences. SF6 gas insulation is not afraid of these. The sealed cavity can prevent external erosion and can work stably even under high altitude and low pressure. For projects like hydropower stations that are located near mountains and water, if you choose it, you don’t have to constantly worry about component malfunctions due to moisture.

Energy Transition

Nowadays, wind power and photovoltaic power are being built in remote areas, and high-voltage power transmission has to cross mountains and rivers. SF6 switchgear supports high-voltage transmission, is compact and easy to transport, and can be built along with new energy power stations. 

High Pollution and Underground Facilities

In chemical industrial parks and coastal salt spray areas, the air is filled with corrosive substances, and ordinary switch cabinets need frequent maintenance. The SF6GIS substation is tightly sealed. SF6 gas itself has strong insulation and is an inert gas. Even if there are chemical particles floating around, you don’t need to worry about corrosion.

Underground substations are more typical. It’s dark and poorly ventilated, so it doesn’t need frequent air changes. Save your manpower and costs.

Key Facilities

In places like hospitals and data centers where power cannot be cut off, or in railway traction power supply systems, the reliability requirements for switch cabinets are extremely high. The SF6 GIS electrical system features rapid arc extinguishing and high electrical endurance. In the event of a fault, it can instantly cut off the current, reducing the tripping rate compared to traditional equipment. When you supply goods to this type of customer, it is definitely a plus.