Large coal mine DC power supply scheme

Abstract

A large coal mine DC power supply scheme put forward by the invention adopts a DC bipolar radial multi-voltage-level network topology, which comprises a ground converter station, a ground DC power supply system and an underground DC power supply system. The ground converter station is a general DC power supply, and is grounded by grounding the DC side of a modular multilevel converter MMC thereof through a large clamp resistor. The ground DC power supply system and the underground DC power supply system are mainly used for transforming and distributing electricity for ground and underground loads. Compared with the existing large coal mine AC power supply scheme, the large coal mine DC power supply scheme has the advantages of relatively simple topology structure, strong power supply capacity, no reactive power balance or harmonic pollution problem and lower operation cost, and can meet the power supply capacity and power supply need of large coal mines from the perspectives of technology and economy. Therefore, the large coal mine DC power supply scheme is a new way of thinking for solving the problem on how to supply power to a large coal mine.

Description

[0001] The invention specifically relates to the selection and research of power supply modes for large coal mines, and belongs to the technical field of coal mine power supply. Background technique [0002] 1. Development and changes of power supply systems in large coal mines [0003] With the construction of large, super-large, safe, high-yield, efficient, and green modern mines and the continuous introduction of advanced coal mining technologies, the power supply system of large coal mines has undergone corresponding changes. [0004] 1.1 Continuous expansion of coal mine power supply capacity and scale [0005] According to statistics from the National Bureau of Statistics: As of 2012, there were 1,050 large coal mines with an annual output of more than 1.2 million tons in the country. One of the characteristics of large, extra-large, safe and efficient modern mines is: large-scale working faces, electromechanical integration of fully mechanized mining equipment And a high degree...

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Problems solved by technology

[0013] 1) The topology of AC power supply systems in large coal mines tends to be complex and large, which reduces the reliability of power supply and increases the difficulty of designing AC power supply systems in coal mines

The literature "Industrial and Mine Automation" No. 12, 2009 "Optimization of Coal Mine Underground High-Voltage Power Supply Network Based on Graph Theory" uses the minimum path method to optimize the power supply structure of coal mine high-voltage AC power grid, and theoretically verifies that this method can improve the safety of coal mine power supply Effectiveness in terms of reliability and reliability, but the optimization space of AC system topology is limited

[0014] 2) The increase in the power supply capacity of coal mines leads to an increase in the short-circuit capacity of the system, the problem of skipping trips becomes more prominent, and the safety of AC system power supply decreases

[0015] 3) The terminal voltage drop cannot meet the requirements for long-distance underground and heavy-load power supply

In order to limit the short-circuit current, the series current-limiting reactor in the cable line will cause the line voltage drop to increase, which will further aggravate the quality problem of the underground power supply voltage

[0016] 4) The wide use of frequency converters makes the harmonic pollution of coal mine power supply system more serious, and the installation of filters will further increase the complexity of system wiring

[0017] 5) The number of cables increases significantly, and the cable cross-section increases, which greatly increases the consumption of metal in coal mines, and the investment cost of cables continues to increase; at the same time, the increase in power supply distance and scale increases the loss on the cable line, which is not conducive to communication economical operation of the system

However, the electromagnetic field energy of wireless power supply has the risk of causing gas explosion. Although the document "Journal of Electrotechnical Society" in 2013, Vol. Judging from the research results, the safety capacity limit of wireless power supply will have limitations when meeting the increasing power supply demand of coal mines. Wireless Communication Causes Electromagnetic Interference

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