Why use transformers in tunnels?

Why use transformers in tunnels?

• 1. Tunnel construction is as follows

Oil immersed transformer manufacturer shared that tunnel construction usually starts with slope opening at the mouth of the tunnel, followed by construction of water interception gutter, leading pipe shed at the mouth of the tunnel, grouting in the pipe shed, drilling, discharging, blasting, hook dregs, blasting, initial support, invert or cushion, drainage plate, geotechnical cloth, waterproof plate, second lining, ditch cable channel and bottom plate.

• 2. Introduction of electrical equipment for tunnel construction

Tunnel portal of large air compressor, tunnel ventilation fan, of whole tunnel hole to lighting, the early stage of the drill, need high power big air volume of air compressor, such as atlas air compressor, air compressor sany heavy industry, xugong, air compressor, a mountain air compressor, the rings such as air compressor in site, the second lining construction of the shotcrete machine such as atlas cement-soil shotcrete machine, numerical control can be moved rock drill, etc., pump, tunnel water pump, if you have any supporting period has several, electric welding machine in general hole construction can't more than 200 kw of power equipment, the hole equipment 200 kilowatts, The power of cement concrete plant is about 400KW, and some construction sites use tunnel boring machine, shield, TBM and other large equipment, which is more than 1000KW. The load will be larger.

• 3. Traditional way of tunnel construction power system

Generally, 380v low-voltage power supply is used within the power supply range of 380v (i.e., within 1,000 meters). If the power supply exceeds 1,000 meters, the engineering team will use large cost to put 10KV high-voltage wire into the hole and solve the power supply problem. Some tunnel holes are covered with 3+1 insulated cables, and some construction sites have three separate single-strand cables with circular section. If the tunnel length is as long as 2000 meters, many projects are unwilling to spend a lot of money to buy 10KV high-voltage hole entry, so they have to increase the section area of 380v wire, which increases the project cost invisibility. Some engineering project quality control departments do not allow the use of high voltage into the hole, so we have to use the cable or use our booster high quality oil transformer equipment.

• 4. The traditional scheme of tunnel construction power system

Military forces are still hay come first, as the basis of tunnel engineering, electric power, but if you don't give force power system, difficult construction is impossible, we as a tunnel construction of power system equipment suppliers over the years, sum up experience as follows, within 500 meters of electric power system, the small equipment without basic can meet the construction reform, if more than 1000 meters using 10 kv high voltage into the hole of the cost is too high, and more than 1000 metres using diesel power generation equipment, the cost is to be reckoned with. In the face of today's construction environment, only *** investment, * reasonable cost can win the quality and benefits of the project. In order to lay a foundation in the tunnel engineering construction industry, go further.

• 5. Problem analysis

There are five problems in tunnel construction:

(1) The tunnel construction site is mostly in the original area, so the voltage is generally not high.

(2) Tunnel tunnel construction site multiple distance from the mouth of the transformer far voltage reduction.

(3) The starting current of multi-line remote equipment in the tunnel construction site is large, and the instantaneous voltage drop is large, so that the equipment cannot be started.

(4) The tunnel construction is longer than 2500 meters and is not willing to use 10KV high pressure.