AC Low Voltage Distribution Cabinet

● Area of application

GGD AC low-voltage distribution cabinet is a new type of low-voltage distribution cabinet designed on the principle of safety, economy, rationality and reliability according to the requirements of the competent superiors of the Ministry of Energy and the majority of power users and design departments. The product has the characteristics of high breaking capacity, good dynamic and thermal stability, flexible electrical scheme, convenient combination, series, strong practicability, novel structure and high protection level, and can be used as an updated product of low-voltage switchgear. GGD AC low-voltage distribution cabinet conforms to IEC439 Low-voltage switchgear and controlgear, GB7251 Low-voltage switchgear and other standards.

● Model meaning

● Electric performance

◆Basic electrical parameters

◆ Main circuit scheme 

There are 129 schemes and 298 specifications for the main circuit of GGD AC Low Voltage Distribution Cabinet(excluding the schemes and specifications derived from the functional changes of auxiliary circuits and the changes of control voltage). Among them, GGD1 has 49 schemes and 123 specifications. GGD2 has 53 schemes and 107 specifications. GGD3 model has 27 schemes and 68 specifications The main circuit scheme was selected by soliciting the opinions of the majority of design and use departments, which increased the scheme needed by power plants. Rated current to 3150A, suitable for distribution transformers of 2000kVA and below. In addition, in order to meet the needs of reactive power compensation, GGJ1 and GGJ2 transmission compensation cabinets are designed, with 4 main circuit schemes and 12 specifications in total.

◆ 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 BGD cabinet to install secondary components. At the same time, NLS has also developed a special LM23D current transformer to meet the needs of power plants and special users when attaching relay protection.

◆Main bus-bar

Considering the price ratio and the feasibility of replacing copper with aluminum, a single aluminum bus can be used when the rated current is below 1500A, and a double copper bus can be used when the rated current is above 1500 A. The manufacturer manufactures the prototype according to this regulation and passes the type test. Of course, the manufacturer can also replace the aluminum bus with a copper bus with the same current capacity according to the requirements of users. The overlapping surfaces of buses are all treated by pond tin process

◆ Selection of electrical components 

▶GGD Type AC low-voltage distribution cabinet mainly adopts advanced electrical components that can be mass-produced in China. At the same time, according to the principle of economy and rationality, some available old products, such as DZ10D and D220, are reserved on the premise of fully considering the feasibility, and obsolete products are not selected.

▶HD13BX and HS13BX rotary operated knife switches are special components designed by NLS to meet the needs of the unique structure of BGGD cabinet. They change the operation mode of the mechanism and retain the advantages of the old products, and are practical electrical components.

▶If the design department selects new electrical components with better performance and more advanced technology according to the needs of users, the GGD Type AC low-voltage distribution cabinet has good installation flexibility, and generally it will not cause difficulties in manufacturing and installation due to updating electrical components.

▶In order to further improve the dynamic stability of the main circuit, NLS designed ZM combined bus clamp and insulation support for GGD cabinet. The bus bar clamp is made of high-strength and high-flame-retardant Pp0 alloy material, which has high insulation strength, good self-extinguishing performance and unique structure. It can be easily combined into a single bus bar clamp or a double bus bar clamp only by adjusting the building block. The insulation support is sleeve-type molded joint with low cost and high strength, which solves the defect of insufficient creepage distance of old products.

● Installation and use

After the product arrives at the receiving place, it should first check whether the packaging is intact, and notify the relevant departments to find the reasons in time when problems are found. For products that are not installed immediately, they should be placed in appropriate places according to the provisions of normal use conditions.

◆ Product installation

 The installation of products shall be carried out according to the installation schematic diagram (see attached figure ), and the basic channel steel and bolts shall be provided by users. When the main bus is installed in a whole row with tin plating, the overlapping surface shall be repaired and leveled, cleaned, coated with neutral vaseline or taken other measures, and then fastened with bolts.

◆The products shall be inspected and tested for the following items after installation and before being put into operation.

▶Check whether the top paint of the cabinet has fallen off and whether the cabinet is dry and clean.

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

▶Whether the on-off of the main and auxiliary contacts of main electrical appliances is reliable and accurate.

▶Whether the ratio and polarity of instrument indication and transformer are correct.

▶Whether the busbar connection is good and whether the insulation supports, mounting 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 reliable and accurate.

▶Whether the contact of the circuit meets the requirements of the electrical schematic diagram.

▶Whether the protection circuit system meets the requirements.

▶Use a 500-volt megohmmeter to measure the insulation resistance value not less than 1 megohmmeter.

◆ Precautions for use

(1) .This product is not installed against the wall, operated on one side (front side), and maintained with double doors. Only qualified professionals can enter or open the product maintenance channel and cupboard door for operation, inspection and maintenance.

(2). air switch after many times, will make the main contact local burns and produce carbon substances, increase the contact resistance, should be regular maintenance and repair of air switch according to its operating instructions.

◆ The manufacturer shall provide the following documents and accessories when supplying:

▶Packing list

▶Product certificate

▶Instructions for use

▶Factory test report

▶Relevant electrical drawings

▶Cabinet door keys, operating handles and spare parts specified in the contract.

●Outline and installation schematic diagram of GGD Type AC low-voltage distribution cabinet