When the EMU shuttles across the vast land, it is like a giant steel dragon. It not only carries the dreams of countless passengers to travel far away, but is also the crystallization of the perfect integration of modern technology and high-speed transportation. Behind this amazing high-speed operation, there is a group of unsung “heroes behind the scenes” playing a vital role, and low-smoke halogen-free flame-retardant cable is one of them. They are like the “neural network” and “lifeline” of the EMU. They are not only responsible for transmitting electricity and control signals to ensure the normal operation of the train, but also, at critical moments, they rely on their special performance to safeguard life safety. Today, TST CABLES will give you an in-depth understanding of the selection requirements and key application areas of low-smoke, halogen-free and flame-retardant cables for EMUs, unveiling the mystery of these “invisible guardians”.
01. About low smoke halogen-free flame retardant cable(LSOH cable)
The biggest highlight of low-smoke halogen-free flame-retardant cable is that it produces very little smoke when burning, which greatly increases the visible distance and buys precious time for passenger evacuation and rescue workers.
Low toxicity is another significant advantage, which eliminates the generation of highly toxic gases at the source, protecting passengers from toxic fumes when they encounter danger and ensuring life safety to the greatest extent.
Furthermore, low smoke halogen-free flame retardant cables have excellent flame retardant properties. When flames strike, it can quickly form a dense carbonized layer on the cable surface, effectively preventing the flames from spreading further, curbing the fire, avoiding the expansion of the fire, creating favorable conditions for firefighting work, and protecting the overall safety of the EMU.
02. Key points for selection: multi-dimensional considerations
Insulation material selection
Insulating materials can be called the “insulating guards” of cables. In the field of low-smoke, halogen-free and flame-retardant cables for EMUs, common insulating materials include polyolefins, cross-linked polyethylene, etc. Polyolefin has excellent electrical insulation properties and can effectively block current and prevent leakage. At the same time, it has excellent chemical stability and can stand firm in complex and changing environments such as humidity and pH changes, and is not easily corroded. Effectively extend the service life of the cable.
Cross-linked polyethylene has excellent heat resistance and can maintain good insulation in high temperature environments, ensuring smooth power transmission. It is particularly suitable for high temperature areas such as EMU power systems.
When making the actual selection, it is necessary to weigh the advantages and disadvantages of various insulation materials based on the precise requirements of the different electrical systems of the EMU and select the most suitable material. For example, for control systems and other lines that require extremely high signal transmission accuracy, polyolefins are given priority to ensure accurate and correct signal transmission; while for high-power, high-heat generating parts such as traction motors, cross-linked polyethylene is more suitable.
Flame retardant performance classification
Flame retardant performance is one of the core indicators of low-smoke halogen-free flame retardant cables, which is related to whether the safety line of the EMU can be stable in the event of a sudden fire. The flame retardant grade of cables is usually divided into detailed categories according to strict standards, the most common ones are Class A, Class B, Class C, etc.
The fire risks in different areas inside the EMU vary. For example, the power compartment where electrical equipment is concentrated has many high-power electrical components. Once an electrical failure occurs, it is very easy to cause a fire, and the fire spreads rapidly. Therefore, Class A flame-retardant cables must be used to build a solid fire barrier. Crowded areas should not be ignored either. Class B or Class A flame-retardant cables are essential to protect the safety of passengers and ensure that passengers have enough time to escape in an emergency.
Conductor material selection
In the field of EMU cables, copper is the best conductor material. It can reduce the loss of electric energy during transmission and improve energy efficiency. At the same time, copper has excellent mechanical strength. Facing complex mechanical challenges such as vibration, pulling, and squeezing during the operation of EMUs, it can still maintain structural integrity and stabilize power transmission. , it is not prone to breakage, deformation and other problems, ensuring stable and reliable power supply.
In view of the actual operating needs of the EMU, copper conductors must be used in the power system, main power supply lines, carriage lighting, air conditioning and ventilation, etc., to ensure strong and stable power supply and ensure high-speed and safe operation of the train.
Temperature adaptability measurement
The temperature of the operating environment of EMUs varies greatly, and they can be found shuttling between areas with scorching heat to areas with ice and snow. This requires that low-smoke halogen-free flame-retardant cables must have super strong temperature adaptability and be able to work stably in “ice and fire”.
When selecting cables, it is important to pay close attention to the temperature parameters of the cables, including the long-term operating temperature range, short-term high temperature tolerance limit, and low temperature resistance index.
03. Revealing the application scenarios
The “energy artery” of the power system
In the power system, low-smoke halogen-free flame-retardant cables play the role of “energy arteries”, continuously delivering electrical energy to various core components.
Low-smoke halogen-free flame-retardant cables used in power systems usually adopt a multi-layer shielding structure. The innermost layer is a copper wire braided shielding layer. The fine copper wires are interwoven with each other, which can effectively block the intrusion of low-frequency electromagnetic fields. The outer layer is supplemented with aluminum The plastic composite tape shielding layer has excellent shielding effect against high-frequency electromagnetic fields. Under the double protection, it ensures the purity and stability of electric energy transmission, providing a solid guarantee for the high-speed and safe operation of the EMU.
The “precision commander” of the control system
In the control system, the “brain” of the train, low-smoke halogen-free flame-retardant cables are transformed into “precision commanders” and are responsible for transmitting control signals.
From the operating instructions issued from the driving console to the precise response of the equipment in each car, the transmission of every signal cannot be missed. Cables must transmit with extremely high fidelity to ensure that signals reach their destination accurately and without error.
To meet this demanding requirement, these cables are designed with materials and structures that provide high signal transmission quality. We select insulating materials with low dielectric constant and low loss tangent. At the same time, we strive for excellence in shielding. By optimizing the weaving density and material selection of the shielding layer, we can fully resist external electromagnetic interference and open up an unobstructed ” Green Channel” ensures the smooth and orderly operation of the EMUs.
“Thoughtful energy provider” for car lighting and sockets
As a “caring energy supplier” for carriage lighting and sockets, low-smoke halogen-free flame-retardant cables effectively curb the spread of fire and reduce the generation of toxic smoke, thus saving precious time for passengers to evacuate. time.
In order to meet the diverse power needs in the car, the cable must also have good flexibility and easy installation. In the narrow space of the carriage, it can turn flexibly and be laid conveniently, making it easy for maintenance personnel to install and maintain it.
With the rapid development of EMUs today, low-smoke halogen-free flame-retardant cables have become a key link in ensuring the safety of passengers’ lives and property and maintaining stable train operation due to their excellent performance. From carefully selected insulation materials, strictly graded flame retardant properties, to conductor materials adapted to different needs, to designs that accurately match operating temperatures, every detail embodies the wisdom and efforts of researchers and engineers, just for Ensure that the EMU can run safely in various complex environments.
TST CABLES has been deeply involved in the rail transit field for 13 years, and all its products comply with relevant certification standards, such as EN45545-2, TB/T1484.3 and other standards. At the same time, TST CABLES has also passed relevant certifications of China Railway cables, such as EMU standard TJ/CL313-2014, GB/T 42740-2023 and CRCC certification. TST CABLES’ main products include EN50264 series, EN50306 series, EN50382 series, thinned cables, data cables, sensor cables, jumper cables, LSOH cable,high temperature resistant cables, high cold cables, fire resistant cables, etc.
TST CABLES products include vehicle equipment, such as traction systems, network systems, jumper systems, driver control systems, brake systems, etc., and railway signals such as vehicle-to-ground wireless communication systems, train operation control systems, computer interlocking systems, track Circuits and automatic blocking systems, etc.
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