Mining Farm Selection and Mining Power Supply Design

Bitcoin Mining & Blog  .  May 05 2023

Mining Farm Selection and Mining Power Supply Design

Site election is the first and most important step in establishing a farm. Establishing a farm in the right place is an important guarantee of long-term profitability for the miner.


Mining Farm Selection

Mining farm selection is the first and most important step in establishing a farm. Choosing the right place to build a farm is an important guarantee for miners to achieve long-term stable profits. Mining farm selection has the following important factors.

The first is electricity price. Miners are clearly aware that electricity price is the top priority consideration factor. Lower price is the first magic weapon for miners to get through bear markets.

The second is the stability of the power supply. In a bear market cycle, the payback period of miners' investment will be extended. In order to reduce costs and improve efficiency, a stable power supply has also become critical. After running for more than 1 year, each power outage will cause damage to the mining machines. A stable power supply can greatly reduce damage to mining hardware.

The third is a stable political environment and sound legal guarantees. When building farms abroad, the political stability of the local government is also an issue that cannot be ignored. Many miners have invested in some high-risk areas and eventually ended up with nothing. Around 2018 and 2019, many miners saw very low electricity prices in Central Asia and invested heavily in Kazakhstan and Kyrgyzstan to build farms. Before many miners recovered their investments, the political situation changed dramatically, and some miners suffered heavy losses in fixed assets.

Operating Bitcoin mining is a business that requires heavy assets and heavy operations. Ample and affordable power supply, a stable political environment, and a sound legal system are among the most important factors. Miners should carefully evaluate the political and economic environment in different regions, especially the long-term political stability, to avoid the risk of losing their investment. At the same time, they should closely monitor changes in electricity prices to ensure the long-term and stable operation of mining machines.

The following provides farm selection elements for different mining machines for your reference.

Air-cooled mining machine

Water cooled mining machine

Oil Cooled Mining Machine

Mine power supply design

The following aspects should be considered in designing a mine power supply system

Safety: Including personal safety and property safety. A safe power supply system is the top priority.

Reliability: To ensure continuous power supply. An unreliable power system will frequently disrupt mine operations.

Simplicity of operation: The system should be as simple as possible while meeting operational needs. Excessive complexity will increase costs and reduce reliability.

Ease of maintenance: Maintenance costs are a major part of total mine costs. An easily maintained system has lower long-term costs.

Flexibility: The system should accommodate operational changes, mine expansion, and evolving needs. Inflexible systems quickly become obsolete, requiring replacement.

Optimized infrastructure investment: Infrastructure costs should be minimized while still satisfying the other conditions. Excessive overdesign sharply increases initial capital costs.

To build an international standard mine, regulations and technical standards must be strictly followed. Formal electrical system design and use of high-specification components can increase costs 4-10 times compared to domestic mines. Design choices can impact total project cost by up to 75%. Experienced professionals should review the design to cut unnecessary equipment, optimize layout, and reduce cabling needs, saving substantial investment.

In summary, a well-designed mine power supply system achieves a balance of safety, reliability, simplicity, flexibility and cost-effectiveness. Close attention to regulations and standards, professional review, and an optimized design can yield major long term savings. Initial overinvestment in excessive infrastructure sharply reduces economic returns.

Choosing the Appropriate Voltage Level for Mine Power Supply

Given a fixed transmission distance and power requirement, a higher voltage results in lower current, reducing power loss and energy usage in the grid. Higher voltage also allows the use of conductors with smaller cross-sectional areas. However, higher voltage demands higher insulation and investment in grid equipment. It also requires more advanced technical skills and expertise to operate and maintain high-voltage electrical equipment.

For mines, primary voltage transformation requires the least investment and provides suitable capacity. When higher capacity is needed, multiple incoming lines should be used if possible.

a. Economic transmission capacity and distance for different voltage levels:

Low voltage grid:

220V, economic transmission capacity of tens to hundreds of kilowatts, distance usually within 1 km.

380V, economic transmission capacity of hundreds of kilowatts to several megawatts, distance around 3 km.

Medium voltage grid:

10kV, economic transmission capacity of 1 to 10 megawatts, distance 10 to 30 km.

35kV, economic transmission capacity of 10 to 100 megawatts, distance 30 to 100 km.

High voltage grid:

110kV, economic transmission capacity of 50 to 500 megawatts, distance 100 to 400 km.

220kV, economic transmission capacity of 200 to 1000 megawatts, distance 300 to 800 km.

In summary, the appropriate voltage level for a mine power supply system depends on the mine's demand for transmission capacity and distance. A higher voltage is more suitable when power must be transmitted over longer distances or at higher capacities. However, higher voltage also increases costs and technical complexity. Where possible, a lower primary transformation voltage with multiple incoming lines can minimize investment while meeting most mine needs.

b. A three-phase circuit consists of a three-phase power supply, a three-phase load, and a three-phase transmission line.

A symmetrical three-phase power supply consists of three sinusoidal voltage sources of the same frequency, equal amplitude, and 120° lag in the initial phase connected in a star (Y) or triangle (△).

Positive sequence: A, B, C

Negative sequence: A, C, B

Zero sequence: The phase sequence with zero phase difference is called zero sequence.

380V power supply is preferred for rack power to save investment in cables. It is recommended to choose a multiple of 3 for the number of mining machines on each rack layer to ensure three-phase balance without adjusting the mining machines.

For example, if there are 12 mining machines on one rack layer, the mainstream air-cooled mining machines currently draw about 15A. Assuming 20A per mining machine for future expansion, with 4 mining machines per phase, the total current is 80A. Options for copper core cables include: 4*25+1*16 or 5*25+2*16. For aluminum core cables: 4*50+1*25 or 5*50+2*25. For a 4-core cable, it is recommended to ground the rack and connect the rack grounding to the system grounding network.

If choosing 220V power supply to the rack, 12 mining machines per layer would draw 240A total, requiring 70 mm2 cables with the same cross-sectional area for live and neutral wires, at higher investment.

Power quality indicators

I. Voltage amplitude: For 35KV and higher voltage levels, the allowed variation range is ±5% of the rated value. For 10KV and lower voltage levels, the allowed variation range is ±7% of the rated value. For single-phase 220V power supply, the allowed voltage deviation is +7% to -10% of the rated voltage.

II. Frequency: The rated frequency of China's power system is 50 Hz. The allowed deviation during normal operation is ±0.2 to ±0.5 Hz.

III. Harmonics: For 6-10 kV voltage, the waveform distortion rate does not exceed 4%. For 0.38 kV voltage, the waveform distortion rate does not exceed 5% (the waveform distortion rate refers to the root square sum of the effective values of each harmonic wave relative to the fundamental wave).

The above covers the content of this blog on mine site selection and mine power supply design. For any details omitted, please feel free to communicate with us and provide your valuable opinions. You may send feedback to <[email protected]>.

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