◆ Main circuit scheme
The main circuit of GGD cabinet is designed with 129 schemes and 298 specifications in total (excluding the schemes and specifications derived from the functional changes of auxiliary circuits and the changes of control voltage).
Including:
GGD1 type 49 schemes and 123 specifications
GGD2 type 53 schemes and 107 specifications
GGD3 type 27 schemes and 68 specifications
The main circuit scheme is selected and compiled by consulting the opinions of the majority of design and use departments, adding the scheme required by the power plant. The rated current is increased to 3200A, which is suitable for distribution transformers of 2000kVA and below. In addition, GGJ1-GGJ2 capacitance compensation cabinet is designed to meet the need of reactive power compensation, with 4 main circuit schemes and 12 specifications in total.
◆ Auxiliary circuit scheme
The design of auxiliary circuit is divided into two parts: power supply scheme and power plant scheme. There is enough space in GGD cabinet to install secondary components.
◆ Selection of electrical components
◇ The GGD cabinet mainly adopts relatively complete electrical components that can be produced in batches in China, such as ME, DW15, DW17, DW45, CM1, NM1, etc. At the same time, according to the principle of economy and rationality, some available old products, such as DZ20, are retained with full consideration of feasibility. Do not use obsolete products.
◇ HD13BX and HS13BX rotary operated knife switch are special components designed to meet the needs of the special structure of GGD cabinet. It changes the operation mode of the mechanism, retains the advantages of the old products, and is a practical new electrical component.
◇ If the design department selects new electrical components with better performance and better technology according to the needs of users, because the GGD cabinet has good installation flexibility, it will not cause difficulties in manufacturing and installation due to the renewal of electrical components.
◇ In order to further improve the dynamic stability of the main circuit, ZMJ type combined busbar clamp and insulation support for GGD cabinet are equipped. The bus clamp is made of high-strength and flame-retardant PP0 alloy material thermoplastic, with high insulation strength, good self-extinguishing performance and special structure. It can be easily combined into a single bus clamp or a double bus clamp by adjusting the building block. The sleeve type molded structure is used for insulation support, with low cost and high strength, which solves the defect of insufficient creepage distance of the old product.
Structure Introduction
◆ The cabinet body of GGD AC low voltage distribution cabinet adopts the type of general cabinet. The frame is partially welded and assembled with 8MF cold-formed section steel. The frame parts and special supporting parts are supplied by the designated manufacturer of section steel to ensure the accuracy and quality of the cabinet body.
The components of the general cabinet are designed according to the module principle, and have 20 mold mounting holes. With high universal coefficient, the factory can realize pre-production, which not only shortens the production cycle, but also improves the work efficiency.
◆ The heat dissipation during the operation of the GGD cabinet shall be fully considered in the design. There are different number of cooling slots at the upper and lower ends of the cabinet. When the electrical components in the cabinet are heated, the heat rises and is discharged through the upper slot, while the cold air is constantly replenished into the cabinet from the lower slot, making the sealed cabinet form a natural air duct from the bottom to the top to achieve the purpose of heat dissipation.
◆ According to the requirements of modern industrial product design, the GGD cabinet adopts the golden section method to design the appearance of the cabinet and the partition size of each part, making the whole cabinet beautiful and fresh.
◆ The cabinet door is connected to the frame with a rotary movable hinge, which is convenient for installation and disassembly. A mountain-shaped rubber and plastic strip is embedded at the folding edge of the door. When the door is closed, the strip between the door and the frame has a certain compression stroke, which can prevent the direct collision between the door and the cabinet body, and also improve the protection level of the door.
◆ The instrument door with electrical components is connected with the frame with multi-strand soft copper wire, and the mounting parts in the cabinet are connected with the cabinet frame with knurled screws. The whole cabinet forms a complete grounding protection circuit.
◆ The surface of the cabinet body is sprayed with plastic, with strong adhesion and good texture. The whole cabinet is in matt color, avoiding glare effect and creating a more comfortable visual environment for the on-duty personnel.
◆ The top cover of the cabinet can be removed when necessary to facilitate the assembly and adjustment of the main bus on site. The four corners of the cabinet top are equipped with lifting rings for lifting and shipping.
◆ The protection grade of the cabinet is IP30, and users can also choose between IP20 and IP40 according to the requirements of the use environment.
Installation and use
After the product arrives at the receiving place, it should first check whether the package is intact, and timely notify the relevant departments to find out the reason if any problem is found. For products that are not installed immediately, they should be placed in an appropriate place according to the provisions of normal use conditions.
◆ Product installation
The installation of the product shall be carried out according to the installation diagram (see Figure 2). The foundation channel steel and bolts shall be prepared by the user. During the installation of the main bus, the lapping surface shall be repaired flat, cleaned, coated with neutral vaseline or other measures, and then the bolts shall be fastened.
◆ After installation, the following items shall be inspected and tested before putting into operation.
◇ Check whether the cabinet top paint falls off and whether the cabinet is dry and clean.
◇ Whether the operating mechanism of electrical components is flexible and free from jamming or excessive operating force.
◇ Whether the connection and disconnection of main electrical components are reliable and accurate, and whether the connection and disconnection of auxiliary contacts are reliable and accurate.
◇ Whether the transformation ratio and polarity of instrument indication and transformer are correct.
◇ Whether the bus connection is good, and whether the insulation support, installation parts and accessories are installed firmly and reliably.
◇ Whether the auxiliary contact meets the requirements, whether the fuse core specification of the fuse is correct, whether the setting value of the relay meets the design requirements, and whether the action is accurate.
◇ Whether the contact of the circuit meets the requirements of the electrical schematic diagram.
◇ Whether the protection circuit system meets the requirements.
◇ The insulation resistance measured with a 500V megohmmeter shall not be less than 10 megohm.
◆ Precautions for use
◇ This product is not installed against the wall, operated on one side (front), and opened on both sides for maintenance of low-voltage distribution cabinet. Only qualified personnel can enter or open the maintenance channel and cabinet door of the product for operation, inspection and maintenance.
◇ After multiple closing and opening of the air circuit breaker, the main contact will be burned locally and produce carbon substances, which will increase the contact resistance. The air circuit breaker should be regularly maintained and repaired according to its operating instructions.
◇ It is forbidden to open and close the disconnector with load.
Factory data and accessories
The manufacturer shall provide the following documents and accessories when supplying
◆ Delivery list
◆ Product certificate and factory test report
◆ Operating instructions
◆ Relevant electrical drawings
◆ Description of main components
◆ Cabinet door key, operating handle and spare parts specified in the contract.
Ordering instructions
When ordering, the user shall provide:
◆ Main circuit distribution system diagram and layout plan, rated working voltage, rated working current, protective device setting current and necessary technical parameters.
◆ Mark the specifications of incoming and outgoing cables.
◆ Model, specification and quantity of main electrical components in the switch cabinet.
◆ If the bus bridge or bus duct is required between the switch cabinets or the incoming cabinet, the specific data such as span, height from the ground, etc. shall be indicated.
◆ When the switch cabinet is used under special environmental conditions, it shall be specified when ordering.
◆ Surface color of switch cabinet and other specific requirements.
