Mining explosion-proof mobile transformer

　　Definition

　　The KBSGZY flameproof (explosion-proof) type mobile substation, also known as the mining mobile transformer, is a power supply and transformation device specifically designed for coal mine underground operations and other harsh environments with explosion hazards. It is composed of a dry-type transformer for mining flameproof mobile substation use, a high-voltage load switch (or high-voltage vacuum switch), a low-voltage feeder switch (or low-voltage protection box), and a high-voltage cable connector, among other components.

　　Structural Characteristics

　　Explosion-proof Performance: The mining flameproof mobile substation has excellent explosion-proof performance and sufficient mechanical strength, making it suitable for use in harsh environments with explosion hazards such as those containing gas, coal dust, dripping water, and methane gas mixtures.

　　Transformer Design: The transformer is designed with a non-core-lifting structure to prevent internal loosening during transportation. The high-voltage side adopts a cylindrical coil, which ensures uniform distribution of impulse voltage and strong resistance to overvoltage. The vacuum pressure impregnation process, along with the co-winding of high and low-voltage coils in the same mold, results in high strength and strong resistance to short circuits. Extensive use of H-class insulation materials provides strong resistance to thermal shocks, high overload capacity, and good insulation performance.

　　Iron Core and Insulation: The iron core is made of high-performance silicon steel sheets, with layered joints processed using an oblique-cut angle. The latest "seven-step" new process is adopted, resulting in low no-load losses and small currents. It is insensitive to temperature and dust, has high fire resistance, does not produce harmful gases, has low noise, and does not pollute the environment.

　　Shell and Heat Dissipation: The shell is designed with a fully corrugated, two-sided opening or top-opening structure, offering advantages such as high mechanical strength, low temperature rise, and good heat dissipation effects.

　　Advantages

　　Energy-saving and Environmentally Friendly: By adopting thin cold-rolled silicon steel sheets with good electromagnetic properties and a magnetic circuit without air gaps, the magnetic resistance of the magnetic circuit is reduced, and the magnetic permeability is improved. Under the same capacity conditions, no-load losses can be reduced by 20%-30% compared to traditional transformers, and no-load currents can be reduced by 60%-70%.

　　Small Size and Light Weight: The transformer uses a wound iron core, which has 4 fewer sharp corners than a laminated iron core, resulting in a compact structure that can save 10%-12% of the total iron core volume. Therefore, its volume is smaller than that of conventional transformers. The wound transformer has a high space utilization coefficient, and the length of the coil wires is reduced, saving copper materials and reducing load losses, thereby reducing the weight of the transformer.

　　Low Noise: Since the wound iron core is wound by several trapezoidal strips in sequence, the silicon steel strips are wound tightly together, and the magnetic conduction direction of the silicon steel strips is completely consistent with the magnetic circuit direction of the iron core, resulting in small vibrations during operation. This can solve the noise problem caused by discontinuous magnetic circuits in laminated iron cores and reduce noise to the lowest level.

　　Strong Short-circuit Resistance: The high and low-voltage coil wires are made of high-quality oxygen-free copper rods, which are vacuum pressure impregnated with Class C solvent-free paint and cured at high temperatures. They have good strength, heat resistance, moisture resistance, overload capacity, and short-circuit resistance.

　　Strong Anti-interference Ability: The protection unit adopts a high-performance PLC as the core data acquisition and processing module, featuring precise control, rapid response, strong anti-interference ability, and stable and reliable performance.

　　Intelligent: It can be integrated into intelligent mine systems in multiple ways, realizing interconnection and intercommunication of mine equipment and providing various communication methods including CAN, RS485, RJ45, WIFI, and 5G to meet the requirements of intelligent mines.

　　Complete Protection Functions: The mobile substation has complete overload, short-circuit, and leakage protection. There are electrical or mechanical interlocking devices between the high and low-voltage switches and between the high-voltage switch and the upper-level circuit breaker.

　　Application Scenarios

　　Coal Mine Underground: As a power distribution device for underground pump stations, conveyors, mining machines, and other electrical equipment in coal mines, it meets the power supply requirements of some heavy-duty mechanized coal mining machines, excavators, etc., with high voltage and large capacity, and can advance with the mining work.

　　Emergency Rescue and Disaster Relief: In emergency situations where equipment has failed or a sudden disaster has occurred, and immediate power supply for emergency rescue and disaster relief is required, the mobile substation can be quickly put into operation.

　　Temporary Power Supply: When exceeding the pre-planned power construction, with a rapidly increasing power demand and relatively long power supply distances, making it difficult to establish a permanent substation, the mobile substation can be put into operation as a temporary substation to alleviate the power supply shortage.

　　Other Industries: It is not only suitable for environments with gas and coal dust explosion hazards in coal mine underground operations but also for harsh environmental conditions in mines (such as gold mines, copper mines, iron mines, aluminum mines, tungsten mines, manganese mines, etc.), coal preparation plants, steel plants, power plants, ports, etc., in industries such as coal, metallurgy, chemicals, and building materials.

　　Usage Precautions

　　Pre-installation Inspection: Before the mobile substation is lowered underground, it must be strictly inspected and undergo a trial run. If any connection looseness, insulation damage, winding moisture, or abnormal operation of instruments and protection circuits is found, it must be repaired and the defects eliminated before use.

　　Installation Location: The mobile substation should be installed in a well-ventilated area to prevent coal dust accumulation from affecting heat dissipation. It should not be placed in areas with water dripping or water accumulation on the floor. If necessary, waterproof protection measures should be added.

　　Cable Connection: The cables (leading out) from the mobile substation must be prevented from being pulled outward to avoid loosening at the sockets or internal connection detachment. It is strictly forbidden to drag the mobile substation by pulling the cables. The cable connectors and all flameproof box covers of the mobile substation are strictly prohibited from being opened while energized. They can only be opened after the power supply at the upper-level substation is cut off. High and low-voltage cables should be strictly inspected for moisture or mechanical damage before being connected. If any is found, they cannot be connected.

　　Operation Specifications: When opening the box cover on the low-voltage side for inspection, the high-voltage load switch must be pulled open first. When opening the box cover on the high-voltage side, removing the high-voltage switch, disassembling the transformer box cover, and unplugging the cable connector, the upper-stage power supply must be cut off, and it must be locked and marked with a warning sign.

　　Regular Inspections: Regular inspections should be carried out to check for loose fasteners and wiring terminals on the mobile substation, rust marks on the flameproof surface, coal dust accumulation and damage on insulation parts, coal dust accumulation inside the box, excessive burning of contacts and arc extinguishing covers, and the insulation resistance should be measured with a megger.

　　Lighting and Grounding: Fixed flameproof lighting lamps should be installed near the mobile substation for regular observation and to avoid accidental collisions. The high and low-voltage switch grounding should be connected to the transformer's external grounding as the main grounding. The auxiliary grounding electrode of the leakage relay should be more than 5m away from the main grounding electrode.