What is Power Distribution?

Power distribution (power distribution) is a link in the power system that is directly connected to users and distributes energy to users. The power distribution system consists of power distribution substations, high-voltage power distribution lines, power distribution transformers, low-voltage power distribution lines, and corresponding control and protection equipment.

[pèi diàn]

English name: power distribution

Chinese name: power distribution

Definition:

High and low voltage power distribution project, as its name implies, is connected to high voltage power distribution cabinets, low voltage switch cabinets, and power distribution equipment that connects cables. Generally, power supply bureaus and substations use high-voltage power distribution cabinets, which are then reduced by transformers to low-voltage switch cabinets, and low-voltage switch cabinets to the power distribution boards. Control boxes and switch boxes are nothing more than the assembly of protective devices such as switches, circuit breakers, fuses, buttons, indicators, meters, and wires into an integrated power distribution device.

High and low voltage power distribution projects generally follow the operating specifications of performing their process week on all and part of the live panels:

1. The maintenance equipment should be separated from the running equipment by obvious signs;

2. The secondary windings with current transformers and voltage transformers should have permanent and reliable protective grounding;

3. When working on the secondary circuit of an operating current transformer, the following safety measures should be taken:

(1) In order to reliably short-circuit the secondary coil of the current transformer, short-circuit tabs and short-circuit wires must be used, and the use of wire winding is prohibited;

(2) It is forbidden to perform any work on the circuit and wires between the current transformer and the short-circuit terminal;

4. When working on the secondary circuit of the voltage transformer in operation, the following safety measures should be taken:

(1) During the secondary circuit energization test, in order to prevent the reverse voltage from being changed from the secondary side to the primary,

In addition, the fuse should be removed once;

(2) Before the circuit is energized or withstand voltage test, the watchkeeper and related personnel should be notified, and someone should be assigned to guard the scene and inspect

Check the circuit and confirm that pressure can be applied only when no one is working;

5. The staff who check the power failure protection and secondary circuit are not allowed to perform any switching without the permission of the staff on duty.

Brake operation.

General requirements for design

(1) From the planning to completion of the power distribution room, the general steps are as follows: determine the size and structure; determine the location; determine the detailed structure; inspect and acknowledge the architectural drawings; construction; complete the building acceptance; power distribution room equipment construction, such as lighting , Air conditioning, fire alarm, etc .; final acceptance.

(2) The design of the substation should be carried out in accordance with the project development plan, so that the long-term and the short-term are combined, and the near-term is the most important. The relationship between the near-term construction and the long-term development should be properly handled, and the possibility of expansion should be properly considered. The design of the substation must be based on the overall situation, take into consideration the overall situation, and comprehensively consider and determine the design plan in accordance with the nature of the load, power capacity, engineering characteristics, regional power supply conditions, and environmental protection and energy saving requirements.

(3) To determine the size and structure of the power distribution room, the function of the power distribution room (transformation, switch station, control, multi-function) must be determined first, and then the installation location must be determined. From the economic point of view, the installation site is expected to be at the load center. Generally, after the main equipment is decided, the remaining building space is fully utilized, so that the approximate building design drawing can be obtained, but for the construction, a detailed structure drawing is required, and the drawing must be approved by the electrical engineer. Construction can be carried out after the construction drawings are completed, and large distribution rooms should be checked frequently.

The grounding electrode should be buried on the concrete foundation in a timely manner. After the completion of the building part of the power distribution room, it should be checked and accepted, and then the auxiliary engineering construction is continued until the final completion.

(4) In order to ensure the safe and reliable operation of electrical equipment, the products used in the design must meet the current national or industry sector product standards. With the continuous development and progress of the country's science and technology, electrical products such as electrical equipment and equipment change rapidly. There are many manufacturers. Electrical engineers must choose between conservative and aggressive.

For equipment selection, priority is given to the use of energy-saving complete sets of equipment and stereotyped products, which are the fundamental measures to implement the state's measures to save energy and ensure design quality. Because the production plant can guarantee the quality of the complete set of equipment through the advanced equipment and technical processing and assembly of skilled workers, as well as good test conditions, it is generally economical and reasonable to choose the complete set of equipment and shaped products.

(5) The type of substation shall be determined according to the condition of the power load and the surrounding environment. For buildings with a heavy load, substations or semi-open-air substations should be attached; however, buildings with a distributed load should be equipped with combined complete substations; and in high-rise or large civil buildings, indoor substations or combined Complete substations; residential areas of large and medium-sized cities with small and dispersed loads should be provided with independent transformer substations; residential areas of small and medium-sized cities and towns with environmental allowances should be installed on pole-type or high-topped substations when the transformer capacity is 315kVA .

14.1.3 Location Selection 1. The following factors should be considered in the location of the transformer room

(1) It should be close to the load center. The shorter the power distribution distance, the smaller the power loss and voltage drop, and the less construction and material costs.

(2) Short power supply distance and easy power supply. When existing buildings or buried objects cause obstacles to construction, comprehensive consideration should be given to the power supply route and the location of the power distribution room should be studied and determined.

(3) The surrounding environment is good. It should not be installed in dusty places, high temperature and humidity places, next to machines with large vibrations, places with severe salt damage around the equipment, or places subject to flooding. However, when unavoidable, appropriate measures should be adopted. In addition, it should not be installed in the place where flammable and corrosive gas may occur and stay. The power distribution room should be located in Classes 0, 1, and 2; otherwise, the electrical products should be explosion-proof structures or explosion-proof construction. The height of the power distribution room in such places from the ground to the first floor should be above 600mm.

Cables should be used for the incoming and outgoing lines of outdoor box-type substations and combined complete substations. The power distribution station should set up auxiliary production houses.

(4) Easy access for equipment. Vehicles should be easily accessible when updating, adding or repairing equipment.

(5) Easy to expand. Considering the increase of load equipment and capacity in the future, the installation site should be left with the possibility of expansion.

(6) It should be avoided as much as possible in the place where the foundation is poor. When it can't be avoided, it is necessary to improve the foundation or piling. In addition, the location of the power distribution room should have no impact on its adjoining ground and have no impact on future development.

(7) The substation should not be located in an explosion-hazardous area, and should not be adjacent to a fire-hazardous area. Otherwise, attention should be paid to explosion protection and fire prevention.