Tianjin Cable Plant Rubber Cable Factory – In mining power supply systems, high-voltage power lines typically use armored cables, which have a much lower failure rate compared to low-voltage rubber cables. Power supply in mining areas is often the weakest link in the system, and the working environment is usually harsh. Therefore, choosing the right type and cross-sectional area of the cable is crucial for ensuring the safety and reliability of the power supply. The following sections discuss the methods for selecting appropriate cables and their cross-sections.
**First, Selection of Cable Model**
The choice of cable model directly affects the reliability, safety, and cost-effectiveness of the power supply system. According to Article 467 of the Coal Mine Safety Regulations, the following criteria must be followed when selecting cables:
1. The vertical difference of the actual installation location should match the specified cable installation requirements.
2. Cables must have conductors with sufficient cross-section to ensure proper earthing protection.
3. Aluminum cables are strictly prohibited in coal mine applications.
4. Fire-retardant cables that have passed inspection and obtained the necessary safety certification for coal mining products must be used.
5. The cross-section of the main cable core must meet the load requirements of the power line.
6. For fixed high-voltage cables, the following apply:
- In shafts or inclined tunnels with angles over 45°, PVC-insulated heavy steel wire armored cables with PVC sheathing or XLPE-insulated thick steel wire armored PVC-sheathed power cables should be used.
- In horizontal tunnels or those with inclinations less than 45°, PVC-insulated steel tape or thin steel wire armored PVC-sheathed cables, or XLPE-insulated steel tape or fine steel wire armored PVC-sheathed cables should be selected.
- Aluminum-core cables may be used between inclined shafts in entry points, underground depots, and central substations; however, copper-core cables must be used elsewhere.
- Fixed low-voltage cables should be M-type or non-armored cables, or mobile rubber-sheathed cables of the corresponding voltage class.
- Non-fixed high- and low-voltage cables must use rubber-sheathed flexible cables that meet Mr818 standards. Mobile and handheld electrical equipment should use dedicated rubber-sheathed cables.
- Cables for lighting, communication, signaling, and control should use armored communication cables, rubber-sheathed cables, or M-type and factory-type plastic cables.
- Aluminum cores should not be used for low-voltage cables, and the use of aluminum-core cables in mining areas is strictly forbidden.
**Second, Selection of Cable Cross-Section**
Cable cross-section selection includes both high-voltage and low-voltage cable sizing, with low-voltage cable selection being the primary concern.
**1. Selection of Main Core Cross-Section**
In general, low-voltage power lines in mining areas tend to be long. During operation, current flowing through the cable can cause voltage drop and heat generation. To ensure the normal operation of the cable and motors, the following four principles should be followed when selecting the cross-section:
1. The temperature rise of the cable during normal operation must not exceed the maximum allowed by the insulation material.
2. The permissible voltage loss on the cable line should be considered during operation.
3. The cross-section must meet the mechanical strength requirements.
4. The cable must also be able to handle the expected load without overheating or causing damage.
Mine cables refer to the ground equipment and underground wiring products used in the coal mining industry. These include cables for mining operations, transportation, communications, lighting, signaling, electric drills, cap lamps, and downhole mobile substations, as well as power cables. Proper selection and installation of these cables are essential for maintaining safe and efficient operations in underground environments.
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