1. Development of box substation
Box type substation is also called the outdoor substations, there are also called combined substation, it is the development in the 70 s and 1960 s Europe and the United States and other western developed countries launched a new outdoor unit substation substation equipment, it has a combination of flexible and convenient for transportation, migration, easy installation, short construction period, the advantages of low operating cost, no pollution, free maintenance, power workers around the world attention. Into the mid - 1990 - s, domestic began to appear simple box-type substation, power division also formulated the ministerial standard accordingly, but is not widely used, to the late 90 s, especially after retrofit project launch, scientific research and development, manufacturing technology and scale have entered the high speed development, are widely used in urban and rural 10 ~ 110 kv variable (match) power stations, factories and mines and flow of small and medium-sized operations in substation construction and retrofit, due to its easy to deep into load centers, reduce power supply radius and improve the quality of the terminal voltage, especially suitable for rural power grids transform, known as the transformer substation construction target mode in the 21st century.
2, box substation characteristics
Box-type substation is mainly composed of multi loop high voltage switch system, armoured bus and transformer substation integrated automation system, communication, remote, measurement, capacitance compensation and dc power electric unit, to install a moisture, rust, dust and rodents, thermal insulation, fire prevention, guard against theft, the case closed, movable steel structure, mechanical and electrical integration, closed operation, mainly has the following features:
(1) Advanced technology, safe and reliable:
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 fireproof 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 to 40 ℃ ~ + 40 ℃ environment under normal operation.
The casing a equipment adopts closed high-voltage switchgear (such as: XGN type), dry type transformer, dry type transformer, vacuum circuit breaker, spring operating mechanism, rotating isolating switch, such as domestic leading technology equipment, products with no exposed live parts, is fully enclosed, the insulation structure, completely 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.
(2) High degree of automation:
Total station intelligent design, protection system adopts microcomputer integrated substation automation 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 distance of smoke alarm, satisfies the requirement of unattended. Need to be able to achieve remote image monitoring.
(3) Factory Prefabrication:
When designing, designers substation actual requirements, make a main wiring diagram and equipment design outside the box, you can choose to provide box variable specifications and models by the manufacturer, all equipment factory a installation, commissioning qualified, truly achieve substation construction factory, shorten the design and manufacturing cycle; Site installation only needs box positioning, cable contact between boxes, outgoing cable connection, protection calibration, transmission test and other commissioning work, the entire substation from installation to commissioning only needs about 5 ~ 8 days, greatly shortening the construction period.
(4) Flexible combination mode:
Box type substation structure is relatively compact, each box constitutes an independent system, which makes the combination of flexible, we can all use box type, that is to say, 35kV and 10kV equipment all installed in the box, constitute the whole box type substation; 10kV switch box can also be used only, 35kV equipment can be installed outdoors, and 10kV equipment and control and protection system can be installed inside the box. This combination is especially suitable for the transformation of old stations in rural power grid transformation, that is, the original 35kV equipment does not move, and only one 10kV switch box can meet the unattended requirements. In short, the box substation has no fixed combination mode, and the user can freely combine some modes in actual situation to meet the needs of safe operation.
(5) Saving investment and quick results:
The box-type substation reduces the investment by 40% ~ 50% compared with the conventional substation of the same scale. The civil engineering (including levy fees) of the box-type substation can save more than 1 million yuan compared with the conventional substation by calculating the 4000kVA scale of the single main 35kV substation. From the perspective of completion and production, it is conservatively estimated that if each station is put into operation 4 months in advance, if the average load is 2000kw and the electricity sales profit is 0.10 yuan/kW.h, the net profit can be increased by more than 600,000 yuan in three months. From the perspective of the operation of box-type substation, advanced equipment selection, especially without oil equipment operation, fundamentally thoroughly solve the problem of the leakage of equipment in conventional substation, substation can implement the state overhaul, reducing maintenance workload, can save running maintenance costs about 100000 yuan a year, the overall economic benefit is very considerable.
(6) Small area:
Taking a 4000kVA single main substation as an example, the construction of a conventional 35kV substation takes up about 3000m2 and requires large-scale civil engineering. The box type substation is selected. The main transformer box and switch box occupy a minimum area of 100m2, including 35KV and other equipment occupy a maximum area of 300m2, which is only 1/10 of the area of the same scale transformer substation. It can be installed and put into production by making full use of streets, squares and corners of factories, in line with the national land conservation policy.
(7) Beautiful appearance, easy to coordinate with the environment:
Body shell adopts aluminium zinc steel plate and container manufacturing technology, design aesthetics, on the premise of guarantee the power supply reliability, select box-type substation shell color, easy to harmony with the surrounding environment, especially suitable for urban construction, such as: urban residential district, railway stations, ports, airports, parks, green belts, such as population concentration areas, it can be used as stationary substation, also can be used as mobile substation, adorn and beautify the environment.
3. Introduction of Xintai 35kV Container Substation
35KV Chengdong Substation is one of the larger container substations in Shandong Province and even in China. It was installed in 2000 and put into operation in only 15 days after installation and commissioning. Focus on four sets of the container station all high voltage equipment, "one" glyph, garden layout, is very spectacular, from left to right in turn of 35 kv switch box, the main transformer box, 10 kv switch box (with control), 10 kv switch box (with compensation capacitor), main transformer box and switch box with capacitor box top structure of interlayer monitor, lower part has into the outlet box, in place to ensure that electrical equipment ventilation cooling; Kyn type hand-car vacuum circuit breaker is selected for 35KV high-voltage circuit breaker, XGN switchgear is selected for 10KV high-voltage switchgear, and dry equipment is used for main transformer, transformer and voltage transformer, so as to fully realize oil-free operation and fundamentally avoid power failure maintenance caused by equipment leakage. The box is equipped with smoke alarm system and remote image monitoring system, the alarm signal and image uploaded to the dispatching for 24h monitoring, can prevent fire, explosion and other accidents and spread, in addition to rain prevention, dust prevention, prevention of small animal entry and other protective measures.
The secondary equipment adopts DSA microcomputer protection and control system, which is distributed. The system integrates the functions of protection, remote control, telemetry and remote communication, and the protection current and measurement and control current are input respectively. The device case is molded into the whole plate, which has the characteristics of compact structure, good sealing, anti-interference and strong seismic ability. In terms of software design, the protection module is completely separated. The large screen displays accident report, alarm information and remote message and telemetry information. The value setting is simple and reliable. The above equipment selection greatly improves the degree of automation of power supply, but also reduces the cost of operation and maintenance, in line with the needs of electric power development.
4, box substation application prospects and prospects
In recent years, box-type substation is the main direction of the current transformation of rural power grid and the construction of substation in the future. However, there are still some deficiencies in some aspects. Specific manifestations are as follows:
(1) the fire problem: box-type substation as a general rule, be fully sealed unattended operation, all the equipment run without oil, and is equipped with a distance of smoke alarm system, and the casing are fire hazards, such as: cable, compensating capacitor, etc., once the emergency fire, is not conducive to ventilation, fire fighting and rescue, should consider to design automatic fire extinguishing system, but this will increase the box-type substation manufacturing cost.
(2) Capacity expansion problem: box type substation is limited by volume and manufacturing cost, and the expansion margin of outlet interval is small. If you want to add 1 or 2 outlet intervals in the original box body, it is more difficult, and the box body must be added to do it.
(3) maintenance problems: box type substation manufacturing considering the manufacturing cost and box volume limit, so that the box type substation maintenance space is small, is not conducive to equipment maintenance, especially accident repair, this is the box type substation congenital deficiency, is unable to overcome the shortcomings.
In short, looking to the future, box substation in China's vast cities, rural areas, industrial and mining enterprises, public building facilities will be widely used, it will be with its cheap and high-quality advantages by more and more people used, so that the operation level of China's power grid to a new level.
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