Box-type substation is a new type of equipment that can penetrate the load center as power and distribution. Its application has just begun in our country, it adapts to the power system transmission and transformation equipment to the oil-free, small, low loss, low noise, complete sets, no pollution, maintenance-free direction, Rapid and convenient, reliable operation, easy to move, less investment, etc., more and more by the user's trust and affirmation, is being widely used.
Second, the structural performance of box-type substation
Box-type substation is composed of high-voltage switchgear, transformers, low-voltage switchgear and power compensation devices in one or several boxes to form a compact variable distribution complete sets of devices. It is mainly used to replace the traditional civil construction substation, Box Type Transformer Substation to achieve variable distribution function. At present, it is mainly used for 3-35KV power distribution system users. High-voltage lines into the box-type substation, after high-voltage switch, from the transformer into a low pressure, and then by the low-voltage main switch and branch switch to the final power equipment. Box variable specifications more specific can be classified as:
1) from the wiring program points: can be divided into single-ended circuit, Box Type Transformer Substation double-ended circuit, ring network three programs.
2) according to the use of conditions: can be divided into both indoor and outdoor forms.
3) by structure: can be divided into one and split. Integral mainly used for outdoor, split mainly used for indoor.
4) from the shell points: can be divided into steel shell, composite panel shell, Box Type Transformer Substation aluminum alloy shell and so on. Third, the characteristics of box-type substation
Box-type substation for the combination of complete sets of products, Box Type Transformer Substation it compared with conventional equipment has the following characteristics:
1) compact, investment province, less land. As the box change is the distribution of several large parts of the layout of the box, through the optimization of design, a reasonable combination of the insulation between the parts greatly reduced. Compressed area and floor space. Box change area of about 6-10M2, Box Type Transformer Substation can be placed directly on the green belt. The design data show that compared with the traditional civil substation, the use of box change can reduce the area of about 80%, and save land acquisition and housing costs about 60%.
2) easy to install, fast construction. Box of the main components and secondary wiring are assembled in the factory, and commissioned by the commissioning and factory test after passing to the scene, the installation only to be suspended in the civil base to be fixed, one day can be installed Put into operation, greatly simplifies the installation, greatly reduce the workload, speed up the construction progress, Box Type Transformer Substation shorten the installation period, saving construction costs, with significant economic value.
3) higher reliability and safety. Ordinary conventional substation electrical equipment, due to long-term outdoors, the insulation and the conductor easily due to atmospheric pollution and deterioration. And the box change due to the characteristics of structural design, Box Type Transformer Substation conductor, internal insulation, contact parts are completely enclosed in the box, the shell of the protection level can generally be IP2X and IP3X or higher, not susceptible to external pollution, , Salt damage, fog, animal and external damage caused by the accident and the higher reliability. The box does not have exposed exposed conductors exposed to the outside of the box, and does not cause shortsheets and electric shock hazards. High pressure side has a complete five anti-measures, Box Type Transformer Substation with mechanical and electrical chain, high security.
4) Universal interchangeability. High and low voltage equipment and components can choose a variety of famous or imported products; transformers can choose dry or oil-immersed transformers, electrical components, versatility, interchangeable Strong sex.
5) easy operation and maintenance. Each room has automatic lighting device, transformer room with rail and transformer car, easy to install the transformer, replace, open the door to the high and low pressure room can be maintained.
6) access to the cable flexible. Box Type Transformer Substation High-pressure introduction using cable or overhead line, low voltage leads to the use of cable, the introduction of the cable can be buried directly or channel laying to high voltage power supply and users can also lead to the poles.
Fourth, equipment selection
1) high voltage switchgear
Box change in the high-voltage switchgear configuration in two ways: one is the circuit breaker, the other is the load switch plus fuse. As the circuit breaker bulky, expensive, and maintenance workload and other reasons, the general design, the recommended choice of the second way. Only in the higher requirements when using the first way. High-voltage switchgear can be used domestic switch or import switchgear.
Transformers can be used oil-immersed transformers or dry-type transformers. Recommended dry-type transformers. Dry-type transformers with low loss, low noise, no oil and other characteristics, to avoid the leakage of traditional oil leaching products, the explosion to the environment pollution, no fire hazards, with good environmental value. Select the transformer, the proposed transformer with temperature was, temperature control, fan and zero sequence protection equipment.
3) low voltage switch
Low voltage switch variety, the user can be optional according to need to recommend low-voltage switch with tripping coil and leakage protection.
Protection of the configuration can be configured according to the needs of users, the proposed box has the following monitoring, alarm, control and protection means:
High-voltage equipment set high-voltage current limiting fuse protection, single-phase short circuit protection, overload protection and five security protection.
Transformer set high temperature start fan and trip protection (high voltage switch trip) and zero sequence protection.
Box Type Transformer Substation Low-voltage equipment installation Main switch has over-current trip, shunt trip, branch switch over-current trip and leakage protection.
Box set to set the emergency trip button and accident sound and light alarm. Sound and light alarm signal from the transformer short circuit, zero sequence, temperature protection, high voltage circuit breaker fault protection, low voltage main switch overcurrent protection, branch switch overcurrent and leakage protection.
Fifth, the application prospects
Because the box-type substation has the advantages of small footprint, quick and convenient installation, excellent electrical performance and mechanical performance, beautiful appearance and low investment, it can be used in urban public buildings, concentrated residential areas, factories, mines and oil fields , Construction sites, roads, ports and other low-voltage distribution sites. Is expected in the near future there will be a broader application prospects.