Mine-used mobile transformer

　　Comprehensive Analysis of Mine-Mobile Transformers

　　I. Core Definition and Function

　　Mine-mobile transformers (also known as mine explosion-proof mobile substations, with models such as KBSGZY) are movable integrated power supply and distribution devices specifically designed for explosive environments such as coal mine underground operations. Their core function is to convert high-voltage power sources of 6 kV/10 kV into low-voltage power sources ranging from 400 V to 3,450 V, supplying power to underground pump stations, conveyors, mining machines, lighting equipment, and handheld electric drills. The equipment features explosion-proof enclosures, offering explosion resistance, impact resistance, and corrosion resistance, making it suitable for harsh environments with humidity, gas, and coal dust.

　　II. Structural Design and Technical Characteristics

　　Modular Composition

　　Consisting of three parts:

　　High-Voltage Distribution Device: A mine explosion-proof high-voltage vacuum switch that supports no-load voltage regulation (±5% or ±2×2.5%) and features an electrical interlock for cover opening.

　　Dry-Type Transformer: Utilizing H-grade insulation materials (such as NOMEX paper) and low-loss silicon steel sheet cores, it reduces no-load losses by 20%-30% compared to traditional models, with noise levels below 65 dB.

　　Low-Voltage Protection Box: Integrates short-circuit, overload, leakage, and undervoltage protection functions, supporting RS485/232 communication interfaces for integration into intelligent monitoring systems.

　　Protection and Cooling

　　Enclosure Structure: Designed with fully corrugated steel plates, available in both side-opening and top-opening styles, offering high mechanical strength and the ability to withstand an internal pressure of 0.8 MPa.

　　Cooling System: Employing natural cooling (ONAN) or forced-air cooling (ONAF), with oil temperature rises not exceeding 60 K, adhering to the GB6450-86 standard for temperature rise limits.

　　Explosion-Proof Performance: Certified by MA coal safety approval and compliant with the GB3836.1-2010 explosion-proof standard, suitable for Class I coal mine underground locations.

　　Intelligent Upgrades

　　Equipped with the KJ2000 mine automation control system, enabling "four remotes" functions (remote control, remote measurement, remote signaling, and remote adjustment), supporting unattended substations.

　　Integrated with PLC data acquisition modules for real-time monitoring of oil temperature, load, gas concentration, and other parameters, achieving a fault warning accuracy rate of 98%.

　　III. Performance Parameters and Selection Guide

　　Key Parameters

　　Capacity Range: From 250 kVA to 6,300 kVA, with common models such as KBSGZY-1600/10 (1,600 kVA, 10 kV/0.4 kV).

　　Impedance Voltage: Ranging from 4.5% to 6%, with short-circuit withstand capabilities meeting the GB1094.5-85 standard, ensuring no winding deformation during low-voltage side outlet short circuits.

　　Efficiency Indicators: Load losses ≤14.64 kW (for a 2,000 kVA model), with total losses reduced by 25% compared to traditional models.

　　Selection Recommendations

　　Load Characteristics: For applications with significant load fluctuations (such as mining equipment), prioritize the S20 series of low-loss transformers, which can achieve no-load losses as low as 1,225 W.

　　Environmental Adaptability: For high-altitude areas (≥1,000 m), derate the capacity, with a decrease of approximately 10% for every 1,000 m increase in altitude.

　　Energy Efficiency Requirements: Although models with Grade II energy efficiency have initial costs 5%-10% higher, the investment difference can be recovered within five years, with annual electricity savings reaching tens of thousands of kWh.

　　IV. Application Scenarios and Industry Cases

　　Typical Application Areas

　　Coal Mine Underground Operations: Providing power to fully mechanized mining faces and heading faces, supporting continuous miners, scraper conveyors, and other equipment.

　　Metal Mines: Supplying power to primary loads such as hoists and ventilators during underground mining operations in iron and copper mines.

　　Tunnel Engineering: Offering mobile power sources for shield machines and wet shotcreting machines during railway and subway tunnel excavations.

　　Industry Cases

　　A Coal Mine in Shanxi: Adopted the KBSGZY-3150/10 mobile substation, achieving unattended operation in underground substations and reducing annual operation and maintenance costs by 40%.

　　An Open-Pit Mine in Inner Mongolia: Deployed the KBSGZY-2000/6 device to support a 220 V portable light lighting system, meeting the demands of railway tunnel excavation.

　　A Chemical Plant in Guizhou: Selected a transformer with an amorphous alloy core, reducing no-load losses to below 0.8 kW and achieving annual electricity savings exceeding 100,000 kWh.

　　V. Market Prices and Supplier Analysis

　　Price Ranges

　　Basic Models (e.g., KBSGZY-500/6): Approximately RMB 88,000 to 128,000, suitable for small mines or temporary power supplies.

　　High-Efficiency Models (e.g., KBSGZY-2000/10-NX2): Approximately RMB 185,000 to 204,000, featuring Grade II energy efficiency and intelligent functions.

　　Customized Models (e.g., with amorphous alloy cores): Priced 20%-30% higher, with a further 60% reduction in no-load losses.

　　Mainstream Suppliers

　　Jiangsu Juli Electric Power Equipment Co., Ltd.: Offers a full range of S20 series products, supports customized designs, and has mature corrugated tank technology.

　　Shandong Jiaxing Electric Co., Ltd.: Focuses on Grade II energy efficiency models, with products certified by MA coal safety approval, suitable for the coal and metallurgical industries.

　　Yancheng Weida Transformer Manufacturing Co., Ltd.: Specializes in transformers for photovoltaic applications, providing dual voltage options of 10 kV/20 kV, and exports to Southeast Asian markets.

　　VI. Maintenance and Troubleshooting Guide

　　Daily Inspection Items

　　Oil Level and Quality: Check the oil level gauge monthly, ensuring oil sample transparency ≥70% and water content ≤20 ppm.

　　Temperature Monitoring: Maintain a top oil temperature not exceeding 85°C, with a temperature rise limit of 60 K.

　　Sound Judgment: Normal operation should produce a uniform "humming" sound; abnormal noises may indicate loose windings or poor core grounding.

　　Common Fault Handling

　　Oil Leakage: Tighten bolts or replace oil-resistant rubber seals, and conduct a seal test (pressure of 50 kPa for 5 minutes) after treatment.

　　Excessive Oil Temperature: Check for散热器 (radiator) blockages and clean the radiator fins if necessary, or switch to forced-air cooling mode.

　　Light Gas Relay Activation: Immediately take gas samples for analysis; if air is present, reset the relay; if combustible gas is detected, shut down for maintenance and inspect the core insulation.

　　VII. Technological Development Trends

　　Material Innovations

　　The application of amorphous alloy cores is expanding, reducing no-load losses to below 0.8 kW (for a 2,000 kVA model).

　　Natural esters (vegetable oils) are replacing mineral oils, improving fire resistance and biodegradability, and complying with the RoHS directive.

　　Intelligent Upgrades

　　Integration of IoT sensors enables remote diagnostics and predictive maintenance, shortening fault warning times to within 10 minutes.

　　Incorporation of digital twin technology simulates the full lifecycle state changes of transformers, optimizing operation and maintenance strategies.

　　Environmental Requirements

　　The recycling rate of scrapped transformers must reach over 95%, with metals and oils classified and processed separately, and the use of harmful substances such as polychlorinated biphenyls (PCBs) is prohibited.