Construction Plan for 380V Power System in Tunnel

1、 Introduction to Tunnel Construction Situation

Tunnel construction generally starts with the slope of the tunnel entrance, followed by the construction of the water interception gutter, the advance of the entrance of the large pipe shed, grouting of the large pipe shed, drilling, discharging explosives, blasting, excavation and hook machine hazard removal, slag removal, supplementary blasting, initial support, inverted arch or cushion layer, drainage board, geotextile, waterproof board, secondary lining, water ditch cable trough, and bottom plate.

2、 Introduction to Electrical Equipment for Tunnel Construction

Large air compressors at the tunnel portal, the overall ventilation fan in the tunnel, the lighting in the tunnel, the early drilling, and the need for high-power and high-volume air compressors, such as Atlas air compressor, Sany Heavy Industry air compressor, XCMG air compressor, Kaishan air compressor, five ring air compressor, etc. are common in the construction site, the second lining construction shotcrete machines such as Atlas cement soil shotcrete machine, CNC movable rock drill, etc., delivery pumps, tunnel water pump, if there are several electric welders in the support period, the general construction in the tunnel will not exceed 150KW of electrical equipment, the portal equipment is 200KW, the power of cement concrete material plant is about 400KW, and some construction sites use tunnel boring machines, shield machine, TBM and other large equipment, the load will be larger if it exceeds 1000KW.

3、 Traditional methods of tunnel construction power system

Generally, 380V low-voltage power supply is used within the range of 380V power supply (i.e. within 500 meters). If it exceeds 500 meters, the engineering team will use high costs to insert 10KV high-voltage lines into the tunnel to solve the power supply problem. Some tunnels use 3+1 insulation wrapped cables, while some construction sites use three separate circular cross-section single stranded cables. If the tunnel length is long, such as 2000 meters, and the project is not far away, spending a lot of money to buy 10KV high voltage to enter the tunnel will have to increase the cross-sectional area of the 380V wire, which invisibly increases the project cost.

4、 Traditional Scheme Problems of Tunnel Construction Power System

As the basic guarantee of the tunnel project - power supply, the army has not moved food and grass first. But if the power system is not awesome, there is no way to talk about the construction. As a supplier of supporting equipment for the power system of tunnel construction for many years, we sum up the experience as follows: in the power system within 500 meters, small equipment can basically meet the construction without modification. If more than 500 meters use 10KV high-voltage power to enter the tunnel, the cost is too high, and if more than 1000 meters use diesel power generation equipment, the cost cannot be underestimated. In the face of today's construction environment, only precise investment and reasonable costs can win the quality and benefits of the project. Only then can we establish a foundation in the tunnel construction industry and go further.

5、 Problem analysis

There are three major problems in the power system for tunnel construction:

1. Tunnel construction sites are mostly located in remote areas, so the voltage is generally not high

2. The construction site inside the tunnel is far away from the entrance of the tunnel, and the transformer has low voltage

3. The construction site inside the tunnel has multiple lines and remote equipment. When the starting current is high, the voltage drop is large, which makes the equipment unable to start.

4. Construction inside the tunnel: The tunnel is over 2500 meters long and unwilling to use 10KV high voltage

6、 Problem Solution

We offer you three sets of solutions:

1. By using a 380V booster, the voltage compensation is increased by 60-100V to a certain value (safe value). When the motor starts, the voltage of the contactor coil will not trip at a low voltage value, and it can be started. After starting, the voltage will drop to around 400V, and 380V will be guaranteed after the load is applied.

2. We will use one 380V to 1200V booster and one 1200V to 400V transformer produced by our company. The 1200V voltage is transmitted through 95 square millimeters to a distance of 2000 meters and then subjected to voltage reduction treatment to transform 1200V into 400V, thereby reducing the line current and minimizing line loss. Enable the end device to operate normally. This requires the wires to be insulated properly.

3. (Suitable for high-precision equipment) We use a voltage regulator from our company to stabilize the voltage. The voltage is raised to a certain value, and the equipment starts with a voltage drop. We compensate for the voltage drop and adjust it before the contactor trips. The equipment starts normally and the voltage returns to its normal value.

7、 Successful case presentation

1. Ma Zhu Expressway and China Railway 11th Bureau of CCCC First Highway Engineering Co., Ltd. use our company's products in Hubei.

2. Beijing Shenyang High speed Railway and China Railway Fifth Bureau 1500 meter equipment with a power of 300 kilowatts

3. Yangling Avenue High speed Railway, China Railway First Bureau Equipment Power 300KW, Distance 1500 meters

4. Shijiazhuang Metro, China Railway Seventh Bureau, equipment 110 kW distance 1000 meters.

5. Hubei Huanhonghu Expressway, China Railway 12th Bureau, equipment power of 100 kW, distance of 1800 meters.

6. Shaanxi Liupanshui Railway, China Railway 12th Bureau, equipment of 100 kW, distance of 2000 meters

7. Zhejiang Shunji Group, Zhangyong Expressway, equipment of 200 kW, distance of 1400 meters

8. Fujian Longnan High speed Railway, China Railway Eleventh, equipment power of 200 kW, distance of 1600 meters

9. Jinliwen Gas Transmission Tunnel, Zhongshui 12th Bureau, equipment of 75 kW, 2000 meters away from the entrance of the tunnel

10. Zhangjiakou Expressway, China Railway 11th, equipment of 75 kW, distance of 2400 meters

8、 Thanks to the unit

Department of Civil Engineering, Shijiazhuang Railway University

Shijiazhuang Zichang Industrial Control Equipment Co., Ltd

The strong support and trust from Sany Heavy Industry, XCMG Group, China Railway Group, China Communications Construction Corporation, and China Water Resources Group towards our company.