High-voltage switchgear for the mining industry

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### Types and Characteristics
- **General mining high-voltage switchgear**: It is applicable to places without the danger of gas and coal dust explosion, such as the underground mine shaft bottom yard and the electromechanical chambers in the main ventilation roadways. For example, the KYGG-2Z-01 general mining high-voltage vacuum switchgear usually has a rated voltage of 6 kV, a maximum working voltage of 7.2 kV, and a rated current of 400 A or 600 A, etc., and it has functions such as control, protection, and monitoring.
- **Flameproof high-voltage switchgear for mining**: It is mainly used in underground coal mines with the danger of gas and coal dust explosion or other similar flammable and explosive environments. Its enclosure has flameproof performance and can prevent the explosion flame and high-temperature gas from spreading to the surrounding environment when an explosion occurs inside, ensuring the safety of the mine.

### Special Requirements
- **Adaptation to Harsh Environments**: The underground environment of mines is humid, dusty, and there may be corrosive gases. Therefore, the protection level of the switchgear should be high, generally not lower than IP43. The enclosure is made of materials that are resistant to corrosion and oxidation, such as aluminum-zinc coated steel plates, to prevent dust, moisture, and chemical substances from entering the inside of the switchgear and affecting the normal operation of electrical components.
- **Meeting Safety Standards**: It must comply with relevant safety standards for mining electrical equipment, such as GB/T 12173-2008 "General Mining Electrical Equipment" and JB/T 8739-2015 "Flameproof High-voltage Distribution Equipment for Mining", etc. It should have a complete grounding system, interlocking protection devices, and leakage protection functions to prevent electric shock to personnel and the occurrence of electrical accidents.
- **Resistance to Vibration and Impact**: During mining operations, vibration and impact will be generated. The structure of the switchgear should have sufficient strength and stability and be able to withstand a certain degree of vibration and impact without damage or failure, ensuring the continuous and stable power supply of the power system.
- **High Reliability and Durability**: Due to the high requirement for the continuity of mining production, a power outage may lead to significant economic losses or even safety accidents. Therefore, the electrical components and overall performance of the switchgear must be highly reliable, with a long service life and a low failure rate.

### Performance Parameters
- **Rated Voltage**: Commonly 6 kV, 10 kV, etc. Some large mines or places with specific requirements may also adopt higher voltage levels.
- **Rated Current**: It is determined according to the power load of the mine and generally ranges from several hundred amperes to several thousand amperes, such as 400 A, 630 A, 1250 A, etc., to meet the power consumption needs of production equipment in mines of different scales.
- **Short-circuit Withstand Current**: It is usually between dozens of kiloamperes and hundreds of kiloamperes, such as 12.5 kA, 20 kA, 31.5 kA, etc., to ensure that the switchgear can quickly cut off the faulty circuit when a short-circuit fault occurs, protecting the safety of equipment and personnel.

### Application Cases
- **Ha Long Mine in Vietnam**: The 6 kV high-voltage control cabinet of ECVV was applied here, which improved the voltage stability and power supply reliability, greatly reduced the power outage time caused by equipment failures, ensured the continuous operation of the mine production line, and improved the overall production efficiency.#TransformerTechnology