Application of Low-Voltage Switchgear in Mines_Hutuo Electric Power Technology Co., Ltd

31-10 2025

Hutuo Electric Power Technology Co., Ltd

Application of Low-Voltage Switchgear in Mines

Mines, as complex and harsh industrial sites, have strict requirements for power supply—demanding high reliability, strong environmental adaptability, and strict safety guarantees. Low-voltage switchgear, as the core equipment for distributing electrical energy to mining machinery, lighting systems, and control circuits, plays a pivotal role in ensuring the continuous, safe, and efficient operation of mining production. Its application in mines covers multiple scenarios such as underground mining faces, surface crushing plants, and mine auxiliary systems, and it must be customized to address challenges like high humidity, dust, vibration, and flammable gas risks in mining environments. Below is a detailed analysis of its specific applications, key functional requirements, and typical configuration solutions.

1. Core Application Scenarios in Mines

Low-voltage switchgear is widely used in both underground and surface mining systems, with clear functional positioning in different scenarios to match the diverse power demands of mining equipment.

1.1 Underground Mining Working Faces

Underground working faces are the core areas of mining production, where equipment such as shearers, scraper conveyors, and hydraulic supports rely on stable low-voltage power supply. Low-voltage switchgear here mainly undertakes two key tasks:

Power distribution for heavy-duty mining machinery: Shearers and scraper conveyors typically require low-voltage power (380V/660V/1140V, the latter two are common in mines) with large current loads. The switchgear must provide stable power output to avoid production interruptions caused by voltage fluctuations or power outages.
Local control and protection: It integrates control units for on-site equipment, allowing operators to start/stop machinery, adjust speeds, and monitor operating status locally. At the same time, it provides overload, short-circuit, and leakage protection to prevent equipment damage or electric shock accidents in the humid, dusty underground environment.

1.2 Surface Auxiliary Production Systems

Surface systems such as crushing plants, ore conveying belts, and water treatment stations are essential for mine logistics and environmental management, and low-voltage switchgear serves as their "power management center":

Centralized power distribution for conveyor belts: Mines often use long-distance conveyor belts to transport ore. The switchgear distributes power to multiple drive motors of the belts and coordinates their operation to avoid uneven load distribution that could lead to belt slippage or motor burnout.
Control of auxiliary equipment: It supplies power and implements protection for surface equipment like crushers, vibrating screens, and water pumps. For example, in water treatment stations, the switchgear controls the start/stop of water pumps based on water level signals, ensuring stable water supply for underground dust reduction and domestic use.

1.3 Mine Safety and Emergency Systems

Safety is a top priority in mines, and low-voltage switchgear is critical to supporting safety systems:

Power supply for emergency lighting and communication: In case of a main power failure, the switchgear automatically switches to the backup power supply (such as a diesel generator or UPS) to ensure continuous operation of emergency lighting in underground roadways and surface control rooms, as well as communication systems like mine telephones.
Dust suppression and fire prevention equipment control: It provides power for underground dust suppression fans and surface fire water pumps. When dust concentration exceeds the standard or a fire alarm is triggered, the switchgear can quickly start the corresponding equipment to mitigate safety risks.

2. Key Functional Requirements for Mining Applications

The harsh and high-risk mining environment imposes unique requirements on low-voltage switchgear, which go far beyond the standards for general industrial scenarios.

2.1 Strong Environmental Adaptability

Mines are characterized by high humidity (underground relative humidity often exceeds 90%), heavy dust, and frequent vibration—all of which can severely affect the performance of electrical equipment:

Dust and water resistance: The switchgear must meet at least the IP54 protection level (dust-tight and protected against splashing water); for underground wet areas, it needs to reach IP65 to prevent dust accumulation on internal components and water intrusion that could cause short circuits.
Vibration resistance: Underground blasting operations and the operation of heavy machinery generate strong vibrations. The switchgear’s internal components (such as circuit breakers, relays, and wiring terminals) must be firmly fixed, and shock-absorbing pads can be installed at the bottom to avoid loose connections or component damage.
Temperature adaptability: It should operate normally in a wide temperature range, typically from -20°C (surface winter) to +40°C (underground high-temperature working faces). For extremely hot areas, heat dissipation holes or axial fans can be added to prevent overheating of internal components.

2.2 Strict Safety Protection Capabilities

Mines face risks such as electric leakage, short circuits, and even flammable gas explosions (in coal mines), so the switchgear must have multi-layer safety protection:

Leakage protection: Underground coal mines and metal mines require the switchgear to be equipped with selective leakage protection devices. These devices can quickly detect small leakage currents (usually ≤30mA for coal mines) and cut off the power supply within milliseconds to prevent electric shock accidents.
Flameproof and intrinsically safe design: In coal mines or mines with flammable gas (such as methane), the switchgear must adopt a flameproof structure (Ex d) for the main body. Its internal components (like control buttons and sensors) use intrinsically safe circuits (Ex ia) to prevent sparks from igniting flammable gases.
Overload and short-circuit protection: It is equipped with low-voltage circuit breakers or fuses with adjustable protection parameters. When mining machinery is overloaded (e.g., a shearer encountering hard rock) or a short circuit occurs, the switchgear can immediately cut off the power to protect the equipment and cables.

2.3 High Reliability and Maintainability

Mining production is highly continuous, and equipment downtime can lead to huge economic losses. Therefore, the switchgear must be reliable and easy to maintain:

Redundant design: For key systems (such as underground working face power supply), a dual-power automatic switching device can be configured. If one power source fails, the switchgear switches to the backup source within 0.5 seconds to ensure uninterrupted power supply.
Easy maintenance structure: The switchgear adopts a modular design, and its front door or side panel can be opened quickly for inspection. Key components (such as circuit breakers and contactors) are standardized and easy to replace, reducing maintenance time.
Fault self-diagnosis: Advanced mining switchgear is equipped with basic fault diagnosis functions, which can monitor parameters such as contact temperature and insulation resistance in real time. When an abnormality occurs, it triggers a local alarm (sound and light) to remind maintenance personnel to handle it promptly.

3. Typical Configuration Solutions for Mining Low-Voltage Switchgear

To meet the above requirements, mining low-voltage switchgear usually adopts a customized configuration plan, combining standard components with mining-specific accessories. A typical 660V low-voltage switchgear for underground coal mines includes the following modules:

Module Name	Core Components	Functions in Mining Scenarios
Power Inlet Module	Molded case circuit breaker (MCCB), voltage transformer	Receives high-voltage power (after step-down) and provides overvoltage/undervoltage protection
Power Distribution Module	AC contactors, thermal overload relays	Distributes power to shearers, conveyors, and other equipment; provides overload protection
Control Module	PLC (Programmable Logic Controller), human-machine interface (HMI)	Realizes local/remote control of equipment; displays operating parameters (current, voltage, temperature)
Protection Module	Leakage protector, flameproof junction box	Detects leakage currents; prevents sparks from igniting flammable gases
Auxiliary Power Module	UPS, backup battery	Supplies power to emergency lighting and communication systems during power outages

Taking an underground coal mine working face as an example, the switchgear works as follows: The high-voltage power is stepped down to 660V by a mine transformer and then enters the switchgear’s power inlet module. The PLC in the control module receives signals from the shearer’s control panel, controls the AC contactor in the power distribution module to supply power to the shearer, and monitors the shearer’s operating current in real time. If a leakage fault occurs, the protection module immediately cuts off the power and triggers an alarm; if the main power fails, the auxiliary power module switches to the backup battery to ensure the operation of emergency systems.

4. Challenges and Optimization Directions

Although low-voltage switchgear has been widely applied in mines, it still faces challenges such as harsh environment adaptation and intelligent upgrading. Future optimization will focus on the following aspects:

Intelligent upgrading: Integrate sensors (temperature, humidity, partial discharge) and wireless communication modules (such as LoRa, which is suitable for underground signal transmission) to realize remote monitoring of switchgear status. This reduces the need for manual inspection in dangerous underground areas and enables predictive maintenance.
Material innovation: Use corrosion-resistant and high-temperature-resistant materials (such as 304 stainless steel for the cabinet body) to improve the switchgear’s service life in humid and corrosive mine environments (e.g., metal mines with acidic water).
Energy-saving optimization: Adopt low-loss components (such as permanent magnet contactors) to reduce the switchgear’s own energy consumption. This is particularly important for mines that pursue energy conservation and emission reduction under the global "dual-carbon" goal.

Conclusion

Low-voltage switchgear is an indispensable "power link" in mining production, with its application covering core production, auxiliary systems, and safety guarantees. Its ability to adapt to harsh environments, provide multi-layer safety protection, and ensure continuous power supply directly determines the efficiency and safety of mining operations. With the development of intelligent mining, future low-voltage switchgear will further integrate digital and energy-saving technologies, evolving from a traditional power distribution device to an intelligent "power management node"—providing stronger support for the transformation of mines towards safety, efficiency, and green development.

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Tags: box-type substation High-voltage switchgear