[box-type substation should be pay attention to the application and design] : 1 box substation overview and application of box type substation is also called the outdoor substation, also known as combined substation, because of its flexible combination, easy to transport, migration, easy installation, short construction period, low operating cost, cover an area of an area small, the advantages of no pollution, free maintenance, widespread attention.
Agricultural network construction...
Overview and application of box substation
Box substation is also called outdoor complete set of substation, also known as combined substation, because it has flexible combination, easy to transport, migration, installation convenience, short construction period, low operating cost, small occupation area, no pollution, free of maintenance and other advantages, has been widely valued.
Site construction (transform), is widely used in urban, rural 10 ~ 110 kv medium and small change (distribution), factories and mines and mobile operation by electrical substation construction and retrofit, because of its easy to in-depth load center, reduce power supply radius and improve the quality of the terminal voltage, especially suitable for rural power grids transform, known as the target mode of the construction of the substation in the 21st century.
Characteristics of box substation
1.1.1 technology advanced security can be * body part adopts the current domestic leading technology and craft, shell generally adopts aluminium zinc steel plate, frame with a standard container material and production process, good anti-corrosion performance, guarantee the 20 years does not rust, photosensitive plate adopts aluminium alloy gusset plate, sandwich with fire-resistant insulation materials, the casing installation of air conditioning and dehumidification equipment, equipment operation is not affected by natural climate environment and pollution of the outside world, can guarantee in 40 ℃ ~ + 40 ℃ under the conditions of normal operation.
The casing a device USES the unit vacuum switchgear, dry type transformer, dry type transformer, vacuum circuit breaker (spring operating mechanism), and other domestic leading technology equipment, the products have no exposed live parts, insulation structure for the whole, can achieve zero accident getting an electric shock, total station can realize oil-free operation, high safety, two by microcomputer integrated automation system, which can realize the unattended.
1.1.2 high automation intelligent total station design, protection system adopts microcomputer integrated automation substation equipment, installation, which can realize "four control", namely, telemetry, remote communication, remote control, remote regulating, each unit shall be independent operation function, protection function is all ready, can be set up the operation parameters of the distance, to control the casing humidity, temperature, and meet the requirements of the unattended.
1.1.3 factory design, as long as the designer according to the actual requirements of substation, make a design of the main wiring diagram and the box outside equipment, can select box change specifications provided by the manufacturer and model, all the equipment installation and commissioning of plant a qualified, truly achieve factory substation construction, shorten the design and manufacturing cycle;
Field installation only requires box positioning, cable connection between boxes, outgoing cable connection, protection fixed value verification, transmission test and other debugging work, the entire substation from installation to operation only takes about 5-8 days, greatly shortening the construction period.
1.1.4 flexible combination mode box substation due to the compact structure, each box constitutes an independent system, which makes the combination mode flexible, we can all adopt the box type, that is, 35kV and 10kV equipment installed in all the boxes, constitute the whole box substation;
35kV equipment can also be installed outdoors, and 10kV equipment and control and protection system box can be installed inside. This combination method is especially suitable for the old transformation of the agricultural network, that is, the original 35kV equipment does not move, only the installation of a 10kV switch box can meet the requirements of unattended.
1.1.5 the investment of provincial and quick-response box-type substation (35kV equipment outdoor layout, 10kV equipment box installation) is 40% ~ 50% less than that of integrated substation of the same scale (35kV equipment outdoor layout, 10kV equipment indoor high-voltage switch room and central control room).
1.1.6 the small area of the above example to illustrate, because the selection of box-type substation no housing construction volume, substation area reduction of about 70m2, in line with the national land saving policy.
1.2 application of box-type substation in the construction (transformation) of agricultural network in the construction (transformation) of agricultural network, the box-type substation model is widely used.
For example, a newly built 35kV terminal substation somewhere in xinjiang has a main transformer capacity of 2 * 3150kVA and a three-phase double-winding power transformer without excitation voltage regulation. The voltage grade is 35 + + 2 * 2.5% / 10.5kv.
35kV overhead feed line is used once, and 35kV vacuum load isolation switch and fast fuse are used together on the high voltage side of the main transformer to replace 35kV vacuum circuit breaker, reduce the cost, and realize linkage brake separation when fuse one-phase fuse and phase-out operation.
The 10kV part adopts the layout of box-type distribution station, and the 10kV cable goes out for 6 times, one of which is the reactive power compensation circuit and one of which is standby.
Both 35kV and 10kV busbars are connected by single busbar without segmentalization.
The transformer is set at the inlet side of 35kV, with a capacity of 50kVA and a voltage level of 35/5% / 0.4kv.
The electrical secondary system of the box-type distribution power station adopts the microcomputer integrated automation system.
Problems needing attention in the design of 2 box substation
2.1 the minimum net fireproof distance between the main transformer and the box shall be met as stipulated in the code for the design of 35-110kv substation, and the minimum net fireproof distance between the building with second-grade fireproof grade and the transformer (oil immersed) shall be 10m.
In the face of external walls of transformers, combustible medium capacitors and other electrical equipment (in line with the requirements of the firewall), when the total height of the equipment plus 3m and 3m on both sides of the equipment are not set within the scope of Windows and doors and no openings, the net distance between the wall and the equipment is not limited;
If in afore-mentioned limits although do not open door window commonly, but when setting fire door, criterion the fire prevention net distance between this wall and equipment should be equal to or be greater than 5m.
Distribution equipment of the lowest rated as secondary, box-type sub-station boxes within a system structure of vacuum switchgear unit, each unit adopts special structure aluminum decorative doors, each interval has double protection at the back of the plate, can open the door, we work in the design, the main transformer and the case between minimum fire interval recommended in 10 m, in order to ensure the safe operation of the substation.
2.2 the outgoing line of 10kV cable shall be laid with steel tubes for aesthetic appearance. The box body of 10kV box distribution station in the substation is generally designed with cement pavement around it, and the terminal pole of 10kV line is generally 10 meters outside the substation wall.
If the cable is buried directly and leads to the line terminal pole, it will bring great inconvenience to the maintenance.
Therefore, the outgoing line of 10kV cable should be laid through steel pipe to facilitate the maintenance and repair of users.
If the terminal pole of 10kV line is far from the substation, the outlet line of 10kV cable from the box body to the enclosure of the substation must be laid through steel pipe.
A new type of overvoltage protector is installed on the line terminal bar at the outlet end of the cable to prevent overvoltage.
3 conclusion
Box-type substation in recent years, is the site construction (transformation) and the direction of the main substation construction, but there are some deficiencies, such as the casing for the extension of the margin between the small, repair the space is lesser, etc., however it to economic and practical advantages of being more widely used, its deficiencies will be improved in the unceasing development.
