GGD Low-voltage switchgear

GGD AC low-voltage distribution cabinet is a new type of low-voltage distribution cabinet designed according to the requirements of the superiors of the Ministry of Energy, the majority of power users and design departments, in line with the principles of safety, economy, rationality and reliability. The inlet method includes the upper and lower sides, the left, middle, right and rear of the cabinet to meet the actual needs of various projects for different incoming lines. At the same time, a fixed position is left in the cabinet to install automatic electromechanical protection boxes for power plants and special users. The product has the characteristics of high segmentation ability, good dynamic and thermal stability, flexible electrical scheme, convenient combination, strong serial and practicality, novel structure and high protection level, and can be used as an upgrade product for low-voltage complete sets of switchgear.

GGD AC low-voltage distribution cabinet complies with IEC439 "low-voltage switchgear and control equipment", GB7251 "low-voltage switchgear" and other standards.

Product model and meaning

GGD□-□□

G: AC low-voltage distribution cabinet

G: Fixed installation and fixed wiring of electrical components

D: Power cabinet

□ (design serial number bit): 1 - breaking capacity is 15kA; 2 - Breaking capacity of 30kA; 3 - Breaking capacity of 50kA (actual number corresponds to specific figures)

□ (main circuit scheme code): The main circuit scheme code (must be combined with the actual number / letter)

□ (Auxiliary Circuit Scheme Code): Auxiliary Circuit Scheme Code (Actual Number/Letter Required)

Structural features:

●The cabinet of the GGD cabinet adopts the form of a general cabinet, the frame is partially welded and assembled with 8MF cold-formed steel, and the frame parts and special supporting parts are supplied by the section steel designated production plant to ensure the accuracy and quality of the cabinet. ●The design of the GGD cabinet fully takes into account the heat dissipation problem during the operation of the cabinet. When the electrical components in the cabinet heat up, the heat rises and is discharged through the upper groove hole, and the cold air continuously replenishes the cabinet from the lower groove hole into the cabinet, so that the sealed cabinet forms a natural ventilation channel from the bottom up to achieve the purpose of heat dissipation.

●GGD cabinet in accordance with the requirements of modern industrial product modeling design, using the golden ratio method to design the shape of the cabinet and the division size of each part, so that the whole cabinet is beautiful and generous, and has a new look

●The movable hinge of the shaft of the cabinet door is connected to the frame, which is easy to install and disassemble. The fold edge of the door is embedded with a mountain-shaped rubber and plastic strip, and the insert between the door and the frame has a certain compression stroke when closing, which can prevent the door from colliding directly with the cabinet and improve the protection level of the door

●The instrument door equipped with electrical components is connected to the frame with multiple strands of soft copper wire. The installation parts in the cabinet are connected with knurled screws between the frame, and the whole cabinet constitutes a complete grounding protection circuit

●The cabinet top coat can be made of polyester orange-shaped baking paint, which has strong adhesion and good texture. The whole cabinet is in matte tone, which avoids the glare effect and creates a more comfortable visual environment for the personnel on duty

●The top cover of the cabinet can be removed when needed, which is convenient for the assembly and adjustment of the main busbar on site, and the four corners of the cabinet roof are equipped with lifting rings for lifting and shipping

●The protection level of the cabinet is IP30, which can be selected between IP20~IP40 according to the requirements of the user's installation site

Electrical performance

1. Basic electrical parameters

2. Main circuit scheme

The main circuit of the GGD cabinet is designed with 129 schemes and a total of 298 specifications (excluding schemes and specifications derived from the functional changes of auxiliary circuits and changes in control voltage).

Among them: GGD1 type, 49 schemes, 123 specifications

GGD2 type, 53 schemes, 107 specifications, GGD3 type, 27 schemes, 68 specifications

The main circuit scheme was selected by soliciting the opinions of the majority of design and use departments, increasing the needs of power plants, and increasing the rated current to 3150A, which is suitable for distribution transformers of 2000KVA and below.

In addition, GGJ1 and GGJ2 capacitor compensation cabinets are designed to meet the needs of reactive power compensation, with 4 main circuit schemes and a total of 12 specifications.

3. Auxiliary circuit scheme

The design of the auxiliary circuit is divided into two parts: the power supply scheme and the power plant scheme. There is enough space in the GGD cabinet to install secondary components, and NLS has also developed a dedicated LMZ3D current transformer to meet the needs of power plants and special users when installing relay protection.

4. Main busbar

When the rated current is 1500A and below, a single copper bar bus is used. When the rated current is greater than 1500A, double copper bar busbars are used. The lap surfaces of the busbars are treated with tin enamel process.

5. Selection of electrical components

a. GGD cabinets mainly use more advanced electrical components that can be mass-produced in China. Such as ME, DZ20, DW15, CW1, CM1, etc.

b. HD13BX and HS13BX rotary operated knife switches are special components designed by NLS to meet the needs of the unique structure of GGD cabinets, which change the operation mode of the mechanism, retain the advantages of old products, and are a practical model electrical component.

c. If the design department selects new electrical components with better performance and more advanced technology according to the needs of users, because the GGD cabinet has good installation flexibility, it will generally not cause manufacturing and installation difficulties due to updating electrical components.

d. In order to further improve the dynamic stability of the main circuit, the bus support of the GGD cabinet adopts a special ZMJ type combined bus clamp and insulation support. The busbar clamp is thermoplastically formed from high-strength, high-flame retardant PPO synthetic material, with high insulation strength, good self-extinguishing performance, and unique structure, which can be easily combined into a single busbar clamp or double busbar clamp by simply adjusting the block-type block. The insulation support is a sleeve molded structure, which has low cost and high strength, increases the creepage distance, and has better safety.

Conditions of use

1. Ambient temperature -5~+40°C. The average temperature in 24 hours is not higher than +35°C.

2. Indoor installation and use, the altitude of the use site shall not exceed 2000m.

3. The relative humidity of the ambient air should not exceed 50% at the maximum temperature of +40°C, and a large relative humidity is allowed at the lower temperature, such as 90% at +20°C, and the effect of condensation should be taken into account due to the change of temperature.

4. The inclination of the device and the vertical surface does not exceed 5 when installed. , and the whole set of cabinets is relatively flat (in line with GBJ232-82 standard).

5. The device should be installed in a place where there is no violent vibration and shock, no conductive dust and gas that destroys insulation, and is not enough to corrode electrical components.

6. When the user has special requirements, it can be negotiated with the manufacturer to solve it.

Installation and use

After the product arrives at the receiving location, first of all, the packaging should be checked to see if it is intact, and the relevant departments should be notified in time to find the cause.

1. Product installation

The installation of the product should be carried out according to the installation diagram, the foundation channel and bolts are prepared by the user, and the lap surface should be repaired and leveled during the installation of the main busbar, treated cleanly, coated with neutral petroleum jelly or other measures, and then fastened with bolts.

2. After the product is installed, the following items need to be inspected and tested before it is put into operation. a. Check whether the top paint of the cabinet has fallen off, and whether the cabinet is dry and clean.

b. Whether the operating mechanism of electrical components is flexible, there should be no jamming or excessive operating force.

c. Whether the on/off of the main electrical appliance is reliable and accurate, and whether the on/off of the auxiliary contact is reliable and accurate. d. Whether the ratio and polarity of the instrument indicator and the transformer are correct.

e. Whether the bus connection is good, and whether the insulation supports, mounting parts and accessories are firmly and reliably installed.

f. Whether the auxiliary contact meets the requirements, whether the core specifications of the fuse are correct, whether the setting value of the relay meets the design requirements, and whether the action is accurate.

g. Whether the contacts of the circuit meet the requirements of the electrical schematic. h. Whether the protection circuit system meets the requirements.

i. The insulation resistance value measured by a 500v megaohm meter shall not be less than 1 megaohm.

3. Precautions for use

a. This product is a low-voltage distribution cabinet that is not installed against the wall, single-sided (front) operation, and double-sided door maintenance. The maintenance passage and cabinet door of the product must be entered or opened by qualified professionals for operation, inspection and maintenance.

b. After the air circuit breaker is closed and divided many times, it will cause local burns to the main contact and produce carbon substances, so that the contact resistance increases, and the air circuit breaker should be regularly maintained and overhauled according to its instruction manual.