Transformer and distribution project is a transformer and distribution system of transformer and distribution equipment for inspection, installation of the construction process.
Transformer and distribution equipment is a general term for transformer equipment and equipment equipped with its main role is to transform the voltage and distribution of electricity, by the transformer, circuit breakers, switches, inductors, reactors, capacitors, as well as high and low-voltage distribution cabinets and other components.
Transformer and distribution equipment installation indoor, outdoor and pole three kinds, are generally installed in the indoor (substation or substation).
(1) transformer installation
①, transformer handling: single weight within 10t transformer is generally used in cars and cranes for handling.
②, transformer inspection: general use of automobile cranes or chain cranes for lifting core, lifting cover inspection.
③, transformer drying: transformer drying time depends on the transformer moisture degree and the choice of drying process. Transformer drying methods such as short-circuit drying and eddy current drying.
(2), circuit breakers, disconnect switches, load switches, reactors, capacitors, high-voltage distribution cabinets, etc., the handling and installation of the general use of mechanical construction.
2, bus, insulators
(1) bus
Adopted in places where the current is large, divided into hard bus and soft bus two kinds. Hard busbar is also known as busbar, soft busbar and includes a combination of busbar.
Bus according to the material can be divided into copper bus, aluminum bus, steel bus three.
Bus according to the shape can be divided into strip, slot, closed plug and heavy several.
(2) insulators
The main role is to insulate and fix the busbar and conductor. Can be divided into indoor and outdoor two kinds, as well as hanging string insulators. Indoor insulators have 1 to 4 holes, and outdoor insulators are 1, 2 and 4 holes.
Insulators are generally mounted on high and low voltage switchgear, bus bridges, walls or supports.
①, low voltage pin insulator. In the 500V overhead lines for insulation and fixed wire.
②, low-voltage butterfly porcelain insulators. Used for terminal, tensioning, corner pole of overhead line below 500V as insulation and fixed wire.
③, terminals (wire nose). There are two kinds of copper and aluminum.
3, control equipment and low-voltage appliances
Electrical control equipment is mainly low-voltage panels (screens), cabinets, boxes of the installation, as well as various types of switches, low-voltage electrical appliances, panels and cabinets, wiring, terminals and other power and lighting engineering commonly used control equipment and low-voltage appliances installation.
The distribution box (panel) can be divided into power distribution box (panel) and lighting distribution box (panel) two kinds according to different uses. According to the installation can be divided into open (hanging) and concealed (embedded), as well as half-open and half-concealed installation. According to the production material can be divided into iron, wood and plastic products, the field is more iron distribution box.
Distribution box (panel) according to the product division of stereotyped products (standard distribution box, disk), non-stereotyped complete sets of distribution boxes (non-standard distribution box, disk) and the field production and assembly of the distribution box (panel). Standard distribution box (panel) is assembled by the factory complete sets of production; non-standard distribution box (panel) is based on the design or actual needs of customized or self-made. If the design is non-standard distribution box (panel), generally need to use the design of the power distribution system to the factory processing customized.
(1) power distribution box
Power distribution box used to be called the power distribution box, due to the latter name is not very accurate, so in the new preparation of a variety of national standards and norms, uniformly known as the power distribution box.
There are many models of power distribution box, XL-3, XL-4, XL-10, XL-11, XL-12, XL-14 and XL-15 are old models. XL-15 type are old products, are still in production and use
(2) Lighting distribution box
Lighting distribution box is suitable for industrial and civil buildings in the AC 50Hz, rated voltage of 500V below the lighting and small power control circuits for the line overload, short-circuit protection and the line for normal conversion.
Because the state only on the lighting distribution box with a unified technical standards for review and identification, and do not do a unified design, and a wide range of domestic manufacturers, so many specifications, models. Selection of standard lighting distribution boxes, should consult the relevant catalogs and electrical design manuals and other books.
4, motor
Motor is the generator and motor collectively, the construction project is referred to in the motor motor. More types of motors, according to the different power supply can be divided into two categories of DC motor and AC motor.
Direct current motors are mainly used for higher speed requirements or the need for large starting torque on the production machinery.
AC motors are widely used, according to the different power supply is divided into single-phase motors and three-phase motors.
Synchronous motors are mainly used to drag the larger power or speed constant machinery. Asynchronous motor according to its structure is divided into two types of squirrel cage and wire-wound.
In accordance with the requirements of the code, the motor must be inspected after installation to test the insulation, such as insulation is low or unqualified motor must be dried.
5, cable laying
According to the function and use, the cable can be divided into power cables, control cables, communication cables, etc., the classification of cables is shown in Table 1. According to the voltage can be divided into 500V, 1000V, 6000V, 10000V, and higher voltage power cables.
Power cables are used to transmit and distribute high-power electrical energy. Control cables are in the power distribution unit to transmit the operating current, connecting electrical instruments, relay protection and control of automatic circuits with
Cable laying methods are as follows:
(1) buried
The cable is directly buried in the ground laying method called buried laying. Buried cable must be armored and anticorrosive layer protection of the cable, bare cable is not allowed to bury the laying. General cable trench depth of not more than 0.9m, buried laying also need to lay sand and cover the top of the brick or protection board.
Buried cable laying procedures are as follows:
Measuring and drawing lines - digging cable trench - sand - laying cable - cover sand - cover brick or protective plate - backfill -Setting marking stakes.
(2) cable laying along the bracket
Cable laying along the bracket is generally in the workshop, plant and cable trench, and the cable is fixed with a card on the installed bracket. The horizontal distance between the power cable bracket is 1m, the control cable is 0.8m. power and control cables can generally be laid in the same trench, the cable vertical laying is generally card, power cable card distance of 1.5m, control cables for 1.8m.
(3) cable laying through the protection pipe
Protection tube will be pre-prepared, and then the cable will be threaded into the tube, the pipe diameter should not be less than the outer diameter of the cable 1.5m, the cable should not be used for the cable, and the cable should not be used for the cable. Less than 1.5 times the outer diameter of the cable. General use of steel pipe as a protection pipe. Single-core cable is not allowed to wear steel pipe laying.
(4) laying on the cable bridge
Cable bridge is a framework for laying cables, through the cable bridge from the power distribution room or control room to the power equipment.
The advantages of cable trays are factory production, serialization, easy quality control, easy to install, after the installation of cable trays and brackets neat and beautiful.
Cable bridge is composed of trays, ladder racks of straight sections, bends through, accessories, and support hangers, etc., is used to support the cable continuity of the rigid structural system of the general term.
6, lightning protection and grounding device
Lightning protection and grounding device consists of grounding pole, grounding bus, grounding jumper, lightning rod, lightning lead, lightning net.
(1) grounding pole
Grounding pole is made of steel pipe, angle steel, round steel, copper or steel plate, generally 2.5m in length, ranging from 3 to 6 per group, directly into the ground, and outdoor grounding bus connection.
(2) grounding bus
Grounding bus laying is divided into indoor and outdoor. Indoor grounding bus is generally fixed along the wall with a card laying. Outdoor grounding bus is generally buried in the ground, ditch digging and filling earth according to the upper mouth width 0.5m, the bottom of the width of 0.4m, depth of 0.75m, 0.34m3 per meter ditch length amount of earth.
Grounding bus more flat steel or round steel as grounding materials.
(3) grounding jumper
Grounding jumper refers to the grounding bus bar in case of obstacles (such as building expansion joints, settlement joints) need to cross the connecting line, or the use of metal components as grounding line needs to be welded connecting line.
High-rise buildings mostly use aluminum windows, in order to prevent side lightning strikes, damage to buildings or injuries, in accordance with the code requirements, the need to install the grounding wire and the wall or column reinforcement connection
(4) lightning rod
Lightning rod is a device to receive lightning, installed in the highest point of the buildings and structures, some important places such as transformer substations, etc., the installation of independent lightning rods, lightning rods made of steel pipe and round steel. steel pipe and round steel made.
(5) lightning lead line
Lightning lead line is from the lightning rod or roof lightning net down along the buildings, structures and metal components lead down the wire. Generally use flat steel or round steel as the lead wire.
Currently most of the building lead wire design using the structural column within the two bars as the lead wire, and the foundation of the reinforcing steel mesh welded to form a large grounding network.
(6) lightning net
Lightning net set at the top of the building, the general use of round steel as a lightning net, some buildings use stainless steel as a lightning net, the cost is higher. According to the specification requirements, high-rise buildings every 3 layers set pressure ring, pressure ring can be used to ring beam reinforcement or another flat steel or round steel in the ring beam for pressure ring, mainly to prevent lateral lightning damage to the building.
7, piping and wiring
Piping and wiring refers to the installation of power supply and control lines from the distribution screen (box) to the electrical appliances, generally open piping and dark piping in two ways.
Explicit piping is fixed with a fixed card will be fixed in the wall, column, beam, roof and steel structure.
Concealed piping is needed to cooperate with the civil construction, the pipe is pre-laid in the wall, roof, beams, columns. Concealed piping has the advantages of not affecting the appearance of beautiful, long service life and so on. Currently commonly used electrical piping pipe materials are welded steel pipe, wire pipe and PVC plastic pipe three.
Electrical concealed piping should be laid along the nearest line, and should reduce bending. Pipes buried in the ground can not be butt-welded, it is appropriate to wear casing welding. Open piping is not allowed to weld, can only use silk.
Wire is the main material in electrical engineering. Insulated wires are divided into rubber insulated wires, PVC insulated wires, nitrile PVC composite insulated wires and so on according to different insulating materials. Insulated wire can be used in various forms of wiring and pipe threading.
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