The following figure is the floor plan of the 3rd assembly workshop of Guangdong Cisco General Electric Power Company. The factory size is 277x177 meters and is divided into seven spans. Three spans with a span of 27 meters to the north and four spans with a span of 24 meters to the south. Taking this factory as an example, we will compare the cost of two distribution schemes: dense bus ducts and traditional cable lines.

The 1 # distribution station is placed at the west end of the third span, with the red thick solid line representing the bus duct and the blue line representing the cable from the bus duct junction box to the low-voltage cabinet. Each plug-in box in the bus duct is equipped with a 500 ampere circuit breaker, which is responsible for supplying power to 2 low-voltage cabinets. 64 plug-in boxes are required, and the capacity of each low-voltage cabinet is designed to be 200-250 amperes.

The specifications and quantities of bus ducts and cables required for Factory Building 3 are as follows:

Usage of bus duct

1200A 170 meters

2.1250A 120 meters

3.1000A 670 meters

4.800A 290 meters

Cable usage

5.5x95mm ^ 2 (282A) or 5x70mm ^ 2 (231A) 1500 meters

The price for 5x95mm ^ 2 is 249.5 yuan/meter,

The total price of cable item 5 is 1500 * 249.5=375000 yuan

According to the results of the last bidding, the total price of the bus duct in Building 3 is 1.624 million yuan. Adding 375000 yuan for the cable part, the total price is approximately 1.99825 million yuan. The bus duct is a turnkey project.

The cable load table is as follows

Cable diameter Cable diameter Air current carrying capacity A Buried current carrying capacity A Weight g/m

The following is a plan to use cables instead of bus ducts:

If cables are used instead of bus ducts, in order to achieve the effect of bus ducts, the cable routing is shown in the above figure (not fully illustrated), and the cables have a star shaped diverging structure. The red part should use 5x240mm ^ 2 cable (530A), or downgrade to 5x185mm ^ 2 cable (442A), with the following cable quantities:

1. 5x240mm ^ 2 (530A) 5632 meters

2. 5x95mm ^ 2 (282A) or 5x70mm ^ 2 (231A) 900 meters

According to the price quoted by the cable manufacturer (average price of copper core cable 0.525/1 meter * 1mm ^ 2),

The price for 5x240mm ^ 2 is 630 yuan/meter,

The price for 5x185mm ^ 2 is 487.5 yuan/meter,

The price for 5x95mm ^ 2 is 249.5 yuan/meter,

The price for 5x70mm ^ 2 is 183.75 yuan/meter,

The total price of cables used in Factory Building 3 is:

The total price for using 5x240mm ^ 2 and 5x95mm ^ 2 cables

5632 * 630 + 900 * 249.5 = 3548160 +224550 = 377,2710

Lower the total price for using 5x185mm ^ 2 and 5x70mm ^ 2 cables

5632 * 487.5 + 900 * 183.75 =2745600 +165375 =291,0975

Summary: The total price of the busbar trunking scheme for Building 3 is 2 million yuan, which is basically a turnkey project. The total price for using the cable scheme is 3.772 million yuan. If cost is considered and the capacity is reduced by one level, the total price should not be less than 2.9 million yuan. The cable needs to be dug in a trench (at least W800 X D1000) in the workshop and constructed by oneself, which will pose many hidden dangers and have a short lifespan in the future. Considering the connection between 32 5x240 cables and the electrical cabinet, the low-voltage electrical cabinet needs to be doubled. So the cost of using bus ducts is much lower than using cables