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<br> <br> select the cable model selected cable type, the power supply reliability, security, and whether the economic rationality have a great relationship. Article 467 of the Coal Mine Safety Regulations establishes the following selection requirements for the selection of cables:
1. The level difference of the actual laying location of the cable should be compatible with the specified cable allowable level difference.
2. Cables shall have conductors of sufficient cross section for protective earthing.
3. Aluminum-coated cables are strictly prohibited.
4. The flame-retardant cable that has passed the inspection and obtained the safety mark of coal mine mining products must be selected.
5. The section of the main cable core should meet the requirements of the power line load.
6. Requirements for fixed laying of high voltage cables:
(1) In shafts and wells with shafts or tilt angles of more than 45°, PVC insulated heavy steel wire armored PVC sheathed power cables, cross-linked polyethylene insulated thick steel wire armored PVC sheathed power should be used. cable.
(2) In horizontal roadways or shafts with an inclination of 45° or less, PVC insulated steel strips or thin steel wire armored PVC sheathed power cables, cross-linked vinyl steel strips or fine steel wire armored PVC shall be used. Sheathed power cable.
(3) Aluminum core cables may be used between inclined shafts in inlets, underground depots, and substations in central substations to substations in mining areas; copper core cables must be used in other locations.
(4) The fixed low-voltage cables shall be Mw-mounted or non-armored cables or mobile rubber sheathed cables of the corresponding voltage class.
(5) The non-fixed high and low voltage cables must use the rubber cable with the standard of Mr818. Mobile and hand-held electrical equipment should use dedicated rubber sheathed cables.
(6) Cables for lighting, communications, signalling, and control shall use armored telecommunication cables, rubber sheathed cables, or M, factory, and factory-type plastic cables.
(7) Aluminum cores should not be used for low voltage cables, and aluminum cores for low voltage cables in mining areas are strictly prohibited.
Cable section selection
The choice of cable cross-section includes the selection of high-voltage cable cross-sections and the selection of low-voltage cable cross-sections, and the selection of low-voltage cable cross-sections is the mainstay.
1. The selection of the cable's main core line Generally, the low-voltage power supply line in the mining area is relatively long. During the operation, the current flowing through the cable will cause pressure drop and heat. In order to ensure the normal operation of cables and motors, the following four principles should be observed when selecting cable sections:
(1) When the cable is in normal operation, its actual temperature rise should not exceed the maximum temperature rise permitted by the insulation.
(2) Select the permissible voltage loss when working on the cable line.
(3) The cable cross-section must be selected to meet the mechanical strength requirements.
Mine cable refers to the ground equipment used in the coal mining industry and the wire and cable products for downhole equipment. Including coal mining machine, transport aircraft, communications, lighting and signal equipment used as well as drill cables, cap lamp wires and power cables for downhole mobile substations.
Cable selection and cable cross-section selection method
In mine power supply systems, high-voltage power supply lines generally use armored cables, and the failure rate is much lower than that of low-voltage power supply. The power supply in the mining area is a weak link in the power supply system and the working environment is poor. Therefore, how to select the type and cross section of the cable is related to the safety of the power supply operation. The following describes the cable selection and cable cross-section selection methods.