Task source
(With economy develops) , the urban electric energy consumption is increased day after day especially the load density downtown rises more quickly as for this problem , some town s increase the voltage of the power grid whose distribution voltage class is improper or it is difficult to repair in their plans for construction and reform of power grids.Our construction of urban power grid shall absorb some foreign useful experience; both the domestic and foreign technology and economy prove the scheme of 24KV is superior to that one of 12KV. This not only lies in the comparison of 24KV and 12 kV but also the power supply radius and capacity almost is once more than those of the latter. Meanwhile the former lowers the loss, unit capacity construction capital and maintenance expense avoids the overhaul and saves the investments. In Chinese cities of high load density if the extension of 12 kV is used continuously, it will be difficult to carry on. In the construction of urban grid, the scheme from 12 kV upgrade to 24 kV is the future development trend, now some provinces and cities have begun to test that scheme.
XBZ2 intelligent/XBJ2 compact box-type substation of 24 kV (20KV) has passed the type test, it is a new generation of 24KV box type substation that is developed by Tianjin Electric Drive Design Institute, Electric Control and Distribute Equipment Institute of china electrical equipment industry association together with more than 70 national enterprises based on the situation of our country , to meet the demand of national increasing of economy development and of the state grid. Intelligent /compact box type substation of 24 kV (20KV).
Overview
XBZ2 intelligent /XBJ2 compact 24kV(20kV) box substation (hereinafter referred to as box substation) absorbs the advantages of foreign box substation, adopts new technology, leading electrical components and high and low voltage automation technology, and meets the requirements of power grid automation and power sector in China. Box-type substation is composed of high-voltage switchgear, distribution transformers, low-voltage switchgear, electric energy metering equipment and power compensation devices assembled in one or several boxes. Intelligent modules are installed on the high-voltage and low-voltage sides to meet the automation requirements of distribution network, and realize remote control, telemetry, remote communication, remote adjustment and computer system management.
This equipment is suitable for urban high-rise buildings, residential quarters, factories and mines, municipal construction, highways, street lamps and other places, and temporary construction. This product has the characteristics of strong complete set, short installation period, small occupied area, low investment, less maintenance, safe and reliable operation, beautiful appearance, long service period and easy coordination with the surrounding environment.
Model and meaning
Use environmental conditions
Normal usage conditions for outdoor box transformers
a) The ambient air temperature shall not exceed+40 ℃ ,and the average temperature measured within 24hours shall not exceed+35 ℃ . The minimum ambient air temperature can be-10 ℃ , -25 ℃ . It should consider sudden changes in temperature.
b) Sunlight radiation of up to 1000W/m2 (sunny noon) should be considered.
c) The altitude does not exceed 1000m.
d) The surrounding air can be contaminated by dust, smoke, corrosive gases, steam, or smoke. The pollution level shall not exceed Level III.
e) Ice cover shall not exceed 1mm for level 1, 10mm for level 10, and 20mm for level 20.
f) The wind speed shall not exceed 34m/s.
g) Consideration should be given to condensation and precipitation.
h) The induced electromagnetic disturbance voltage in the secondary system shall not exceed 1.6kV.
Special usage conditions
Normal usage conditions exceeding 3.1 should be resolved through coordination between the manufacturer and the user
The main technical parameters
Ur: high voltage side: 24kV; low voltage side: 0.4kV
auxiliary circuit: AC 110V, 220V, 380V；; Dc 24V
Transformer rated capacity: 100,125,160,200,250,315,400,630,800,1000,1250,1600kVa
Rated current (Ir): high voltage side: 400,630 A; low voltage side: 2500A max
The rated frequency (fr): 50HZ
The rated short-time withstand current (Ik):
High-voltage switchgear: 16kA 2s(4s), 20kA 2s(4s)
Low voltage switchgear: 15kA for 315-500kVA
30 kА for 630-1600kVA
Test time: 1s
When the transformer capacity is less than 315kVA, the test is exempted.
Enclosure protection level: not less than IP23D
Structural features
1. This design considers the territory, environment and variety of customer demands, it employs the modular structure combined with following types.
According to the HV switch connecting with the power grid: ring net type, terminal type, HV energy metering type, LV energy metering type.
According to the type of built-in transformer: oil- immersed full- seal transformer and dry- type transformer.
According to the type of HV switch: vacuum type load switch and combination unit switch gear, SF6 load switch and combination unit switch, gas-filled switchgear
According to the material of box body (enclosure) : metallic enclosure and non- metallic enclosure The metallic enclosure and frame are welded with the beam channel and steel I beam, the side wall and top cover is of two-layer assembly, the outer has the hoisting pin and mounting pin, the metallic door has the good earthing line and the under frame and foundation has the connecting earthling conductor. There are doors installed on both sides of transformer, which facilitate the installation and repair of the transformer; and safe and isolating net doors to prevent person entering into electrical isolating area by mistake and guarantee the safety of equipment and human.
2. Good heat insulation and ventilation measures are available: all sides of the box are of double-layer structure, and the top layer of the box is also provided with heat insulation materials, which effectively reduces the indoor temperature rise caused by sunshine. The side door of the high-pressure room is provided with an automatically controlled ventilation fan, which can ensure the safe operation of the transformer under full load in high temperature season.
3. The HV switchgear af HV side provided with five-prevention measures and there is an energized reliable lock with the transformer compartment to ensure the human security. can reach IP23D; It has good rain-proof performance.
4. Convenient operation and maintenance
There are some visible marks outside of the box type substation , indicating the HV compartment, through opening the compartment doors, they can be easily operated and repaired, each compartment has the automatic lighting device even the compartment of transformer is used for installing , maintaining and changing the transformer in addition LV compartment is of force connection and for repairing the channels.
5. Nice appearance and durability
The enclosure is made of AL-plates and color steel sandwich plates, it is given the pre- treatment and plating treatment , besides, it also can be nonmetallic enclosure made of a glass fiber and special cement and with the special technology so it has the obvious advantage like the strong plasticity
of appearance, corrosion resistance, heat isolation and sound isolation etc. The surface coating is beautiful and durable, with high cohesion and soft color sense.
Type test
3pcs samples of XBJ2 intelligent XBJ2 compact box-type substation of 24kV(20kV) have passed the type test conducted by National Center of Ouality Supervision and Inspection for Electrical Control and Distribution Equipment, and they have met the requirements of relevant standards.
Key features and innovations
XBZ2 intelligent /XBJ2 compact 24kV(20kV) box substation is creative and leading as follows:
1)There are intelligent modules isntalled at HV and LV circuits,they can pass the operation information and control signal to the upper machinevia the field bus or intelligent controller to realize the remote control，remote sensing，remote signaling， remote regulating and system management.It covers the serious shortage of domestic similar products in the intelligent control.The wireless MODEM employs GPRS mode te connect with the user's mobile phone，so that user can monitor the operationsituation of box-type substation anywhere，anytime.
2)It uses the solid-encapsulated isulating switch，which has the features such as the high reliability zero disicharge,zero pollution，free maintenance,small volume and light weight，etc., besides，this switch is more environmental protection and safe.
3)The innovation point rests with that the Cu-A1 composite bus is used as the carrying-current conductor in the substation which can lower the consumption of Chinese limited copper resource to the larger extent.
4)It is designed with the assembled structure，with the features of strong completeness，high production efficiency，short installation period and low transportation cost.
5)It uses the nitrogen spring instead of the traditional windproof hook，can solve such problem that the traditional windproof hook easily comes off； and this spring is very nice and takes te convenience for the operation.
6）XBJ2 compact box-type substation of 24KV，through the structure optimization of the high voltage components like the HV load switch fuse， presents the perfect combination unit that is placed into the oil tank of transformer and immersed in the oil.LV switchgear is minimized to reduce the volume of combined substation，so its floor space is only 1/3~1/5 that of usual products.The box body of transfomer can disperse the heat naturally if it is exposed in the air，therefore，it has the good operation conditions.
What's more，it possesses the outstanding advantages like the high mechanical strength，low loss，low noise，low tmperature rise，strong overload capacity，etc., its structure presents the type of Chinese character.
7）XBJ2 compact 24kV(20kV) box-type substation has applied for one invention patent and eight utility model patents in many innovations such as control principle, structure and new components, which have been accepted.
