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]]>This entry is reviewed by the “Science China” Science Encyclopedia entry writing and application work project.
Voltage class (voltage class) The rated voltage class series of power systems and power equipment. The rated voltage is the normal voltage specified by the power system and power equipment, that is, the nominal voltage related to certain operating characteristics of the power system and power equipment. The actual operating voltage of each point of the power system is allowed to deviate from its rated voltage to a certain extent. Within this allowable deviation range, various power equipment and the power system itself can still operate normally.
The Chinese name of voltage class The foreign name of voltage class is used in power systems and power equipment to define the rated voltage levels of power systems and equipment
table of Contents
1 category
2 Suitable transmission distance and power for different voltages
3 Reasonable configuration of urban power grid voltage levels
classification
General division of voltage levels:
1: Safety voltage (usually below 36V);
2: Low voltage (divided into 220V and 380V);
3: High voltage (10KV-220KV);
4: Ultra-high voltage 330KV-750KV;
5: UHV 1000KV AC, ±800KV DC or more;
The highest AC voltage level in my country is 1000kV (Changzhi-Jingmen line), which was put into operation on December 30, 2008. Transmission lines under construction (Xiangjiaba-Shanghai, Jinping-Sunan UHV DC 800kV), under which there are 500kv, 330kv, 220kv, 110kv, 66kv, 35kv, 10kV, 380/220V, of which 60kV is left over due to historical reasons The ones that come down only exist in the northeast of my country;
The highest DC voltage rating in my country is ±800kV (South Hami-Zhengzhou, Xiangjiaba-Shanghai, Jinping-Southern Jiangsu, Xiluodu-West Zhejiang, Lingzhou-Shaoxing), ±660kV (East Yinchuan-Jiaodong), ±500kV (Gezhouba —Shanghai Nanqiao Line, Tianshengqiao—Guangzhou Line, Guizhou—Guangdong Line, Three Gorges—Guangdong Line), plus ±50kV (Shanghai—Shengsi Islands Line), ±100kV (Ningbo– -Zhoushan Line), China Southern Power Grid has built a ±800kV UHV DC transmission line-Yunguang UHV DC transmission line, and the State Grid Corporation has built two ±800kV UHV DC lines, namely Xiangjiaba-Shanghai ±800kV UHV DC line and Jinping-Sunan ±800kV UHV DC line.
Commonly used voltage levels in my country: 220V, 380V, 6.3kV, 10kV, 35kV, 110kV, 220kV, 330kV, 500kV, 1000kV. The power system is generally composed of power plants, transmission lines, substations, distribution lines, and electrical equipment. Generally, voltage lines above 35kV are called power transmission lines.
Voltage lines of 35kV and below are called distribution lines. The voltage above 1kV is called “high voltage”, and the voltage below 1kV is called “low voltage”.
my country stipulates five safety voltages: 42V, 36V, 24V, 12V, and 6V.
Among the AC voltage levels, 1kV and below are usually called low voltage, 1kV and above, 35kV and below are called medium voltage, 35kV and above, 220kV are called high voltage, 330kV and above, and 1000kV are called ultra-high voltage, and 1000kV and above are called special voltage. high pressure.
Among the DC voltage levels, ±800kV is called high voltage, and ±800kV and above is called UHV [1].
Suitable transmission distance and power for different voltages
Voltage level Transmission distance KM Transmission power KW
0.4KV 0.6 or less 100 or less
6.6KV 4~15 100~1200
10KV 6~20 200~2000
35KV 20~70 1000~10000
66KV 30~100 3500~30000
110KV 50~150 10~50MW
220KV 100~300 100~ 500MW
330kV 200~600 200~800MW (Northwest)
500KV 150~850 1000~1500MW
750KV more than 500 2000~2500MW
1100KV 1000~1500 3000MW and above [1]
1500KV
Reasonable Configuration of Voltage Level of Urban Power Grid
(1) With the increase of load, the adaptability of the voltage level sequence currently used in some areas of my country is limited, and it is necessary to adopt a new voltage level sequence. The implementation of the voltage level configuration requires an in-depth feasibility study according to the specific conditions of the city.
(2) For areas with higher final load density, a gradual transition to a higher medium voltage distribution voltage can be considered. For areas with lower final load density and longer power supply distances, higher medium voltage distribution voltages can also be considered.
(3) In order to avoid affecting the reliability of power supply during the introduction of new voltage levels, the installation of tie transformers can be used to connect power grids with different distribution voltage levels to the grid.
(4) For areas where the new voltage level sequence is adopted, the internationally accepted method of gradual cannibalization can be adopted. After several years of gradual transition, a target voltage level sequence mode can be formed. [2]
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]]>The post Slim Style Switch Power Supply appeared first on Distribution board, circuit breaker, fish tape, cable marker,anti vandal switch, Thermostat: ezitown.
]]>Switch Mode Power Supply (SMPS), also known as switching power supply and switching converter, is a high-frequency power conversion device and a type of power supply. Its function is to convert a level of voltage into the voltage or current required by the user through different forms of architecture. The input of the switching power supply is mostly AC power (such as mains power) or DC power, and the output is mostly equipment that requires DC power, such as personal computers. The switching power supply converts the voltage and current between the two.
Switching power supply products are widely used in industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, communication equipment, power equipment, instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerators, liquid crystal displays, LED Lighting, communication equipment, audio-visual products, security monitoring, LED strips, computer cases, digital products and instruments.
In the field of switching power supply technology, people are developing related power electronic devices.
320W single group switching power supply
320W single group switching power supply
While developing switching frequency conversion technology, the two promote each other to promote the development of switching power supplies in the direction of light, small, thin, low noise, high reliability and anti-interference with a growth rate of more than two digits each year. Switching power supplies can be divided into AC / DC and DC / DC.
Miniature Low Power Switching Power Supply
Switching power supplies are moving towards popularity and miniaturization. Switching power supplies will gradually replace all applications of transformers in life. The application of low-power micro-switching power supplies must first be reflected in digital display meters, smart meters, mobile phone chargers and so on. At this stage, the state is vigorously promoting the construction of smart grids, and the requirements for energy meters have greatly increased. Switching power supplies will gradually replace the application of transformers on energy meters.
Reverse series switching power supply
The difference between an inverting series switching power supply and a general series switching power supply is that the voltage output by this inverting series switching power supply is a negative voltage, which has the opposite polarity to the positive voltage output of a general series switching power supply; The inductor L only outputs current to the load when the switch K is turned off. Therefore, under the same conditions, the current output by the inverting series switching power supply is less than the current output by the series switching power supply.
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]]>The post Low Voltage Capacitor Bank Cabinet appeared first on Distribution board, circuit breaker, fish tape, cable marker,anti vandal switch, Thermostat: ezitown.
]]>TBB0.4 Series Intelligent Reactive Power Compensation Installation is a revolutionary electricity saving product developed by ourselveson the basis of the reference to the structure of opponents from the world. It is equipped with microcomputer control system, which can automatically com pensate the reactive component through intellectualized track.
Basic Principles of the Installation
The automatic reactive-power compensation controller samples thereactive current of the power line. Then the microcomputer n the controller analyzes the sampled current and transmits the control signal to the outputrelay, which controls the special contactor .
of CJ19 type switching capacitor in the compensation cabinet, so as to control the switching of bsmj0.4 serialself-healing type low voltage shunt capacitor and reduce the line loss andimprove voltage quality.
Main Technical indexes
1.Service conditions: Altitude ≤ 2000m. ambient temperature -25℃ ~45℃, humidity ≤ 90% at 20℃ and ≤ 50% at 40℃, and mounting gradient ≤5°.
- Rated voltage: 540VAC, 60Hz.
- Rated output:260Kvar.
- Operating voltage range (0.85-1.10)times of rated voltage.
- Max allowable current: 1.30 times of rated current.
- Number of circuits controlled: 11
- Switching time: 30-90s/time, adjustable.
- Operation method: Automatic, continuous operation.
- When the load varies from 5% to 100% the cosφ value remains over 0.95.
General Description
- Small size facilitates installation and maintenance of equipment is designed specially for reactive compensation of three-phase transformer with rated voltage 380V and capacity 50-1000KVA.
- Controlled by microcomputer and adopting automatic compens ation mode, it has complete functions and reliable performance LEd digital display shows the power factor of power line, ranging from lagging(0.00-0. 99 )to leading(0.00-0.99).
- The set values of Cosφ, delay and over-voltage can be set through three functional set keys on the panel keyboard and shown on the digital display. Concise man-machine dialogue facilitates the operation.
- With pilot lamp indicating the lagging, leading to operate and over voltage, LED hints program input.
- With over-voltage protection function, it is safe in operation. The over-voltage set value has been set at 540V in factory. The users can reset is between 500V and 580V according to their own needs When power line voltage exceeds the set value, Cosφ digital meter is changed automatically and shows the present voltage value of power line. At the same time, it switches off the input capacitors automatically, quickly and step by step. Once the voltage regains normally, This installation will work automatically again.
6. Having strong anti jamming capability it can resist interference pulse of 2000v input directly through power line. The index exceeds national special standard.
7.Protection degree of Low Voltage Capacitor Bank Cabinet:IP54
Main Technical Parameter of Low Voltage Capacitor Bank Cabinet
|
Model |
Rated output (kvar) |
Capacitors |
Dimmensions(mm) H*S*T |
|
TBB0.4-40-3 |
40 |
4stepsx 10kvar |
1700x600x600 |
|
TBB0.4-50-3 |
50 |
5steps x 10kvar |
1700x600x600 |
|
TBB0.4-60-3 |
60 |
6stepsx 10kvar |
1700x600x600 |
|
TBB0.4-80-3 |
80 |
8steps x 10kvar |
1700x600x600 |
|
TBB0.4-100-3 |
100 |
10stepsx 10kvar |
1700x600x600 |
|
TBB0.4-120-3 |
120 |
10stepsx 12kvar |
1700x800x600 |
|
TBB0.4-160-3 |
160 |
10stepsx 16kvar |
1700x800x600 |
|
TBB0.4-200-3 |
200 |
10stepsx20kvar |
1700x800x600 |
|
TBB0.4-250-3 |
250 |
10stepsx25kvar |
1700x800x600 |
|
TBB0.4-300-3 |
300 |
10stepsx30kvar |
1700x1000x600 |
|
TBB0.4-400-3 |
400 |
10stepsx40kvar |
1700x1000x600 |
|
TBB0.4-480-3 |
480 |
12stepsx40kvar |
1700x1200x600 |
CAPACITOR BANK CABINET circuit
Low Voltage Capacitor Bank Cabinet 10
Low Voltage Capacitor Bank Cabinet9
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