Meaning of Model Designation

G: AC Low-Voltage Distribution Cabinet
G: Fixed Installation and Wiring of Electrical Components
D: Power Supply Cabinet

Operating Environmental Conditions

Electrical Performance

1.Basic electrical parameters

Model	Rated Voltage (V)	Rated Current(A)		Rated Short-Circuit Breaking Current(A)	Rated Short-Time Withstand Current(A)	Rated Peak Withstand Current(A)
GGD1	380	A	1000	15	15	30
		B	600(630)
		C	400
GGD2	380	A	1500(1600)	30	30	63
		B	1000
		C	600
GGD3	380	A	3150	50	50	105
		B	2500
		C	2000

2. Main Circuit Schemes
The main circuit of the GGD cabinet is designed with 129 schemes, totaling 298 specifications (excluding derived schemes and specifications resulting from functional changes of auxiliary circuits or variations in control voltage).

Cabinet Type	Number of Schemes	Number of Specifications
GGD1	49	123
GGD2	53	107
GGD3	27	68

The main circuit schemes are selected based on opinions collected from a wide range of design and user departments. Schemes required for power plants have been added, with the rated current increased to 3150A, making it suitable for power distribution transformers of 2000kVA and below.
In addition, GGJ1 and GGJ2 capacitor compensation cabinets are designed to meet the needs of reactive power compensation, featuring 4 main circuit schemes and 12 specifications in total.

3.Auxiliary Circuit Schemes

The design of the auxiliary circuit is divided into two parts: power supply and consumption schemes, and power plant-specific schemes. The GGD cabinet provides sufficient space for installing secondary components. Meanwhile, NLS has developed a dedicated LMZ3D-type current transformer to meet the requirements of relay protection systems installed in power plants and for special users.

4.Main Busbar

Considering the cost-performance ratio and feasibility of replacing copper with aluminum, double copper busbars are adopted for a rated current of 1500A. The AC low-voltage distribution cabinet complies with standards such as IEC 60439 "Low-Voltage Switchgear and Controlgear Assemblies" and GB 7251.1 "Low-Voltage Switchgear and Controlgear Assemblies".

The overlapping surfaces of the busbars are all treated with tin plating technology.

5.Selection of Electrical Components

a. The main components of the GGD cabinet mainly use ME, DW15, and DZ20 circuit breakers. It also uses electrical appliances developed and produced with imported technologies in recent years, such as products of the CW1, CM1, M, and F series. Obsolete products are not used.

b. The HD13BX and HS13BX rotary-operated knife switches are special components designed by NLS to meet the needs of the unique structure of GGD cabinets. They have changed the operating mode of the mechanism while retaining the advantages of the old products, and are a new type of electrical component.

c. If the design department selects new electrical components with more advanced performance according to user needs, due to the good installation flexibility of the GGD cabinet, it will generally not cause difficulties in manufacturing and installation due to the update of electrical components.

d. To further enhance the dynamic stability of the main circuit, NLS has designed the ZMJ-type combined busbar clamp and insulating support specifically for GGD cabinets. The busbar clamp is thermoformed from high-strength, high-flame-retardant PPO alloy material, featuring high insulation strength, excellent self-extinguishing performance, and a unique structure. It can be easily combined into a single busbar clamp or double busbar clamp simply by adjusting the modular spacers. The insulating support adopts a sleeve-type molded structure, which is low in cost and high in strength, overcoming the defect of insufficient creepage distance in old products.

V. Structural Characteristics

1、The cabinet of the GGD type AC low-voltage distribution switchgear adopts the form of a universal cabinet. The frame is partially welded with 8MF cold-formed section steel. The frame parts and special supporting parts are produced and supplied by our company to ensure the accuracy and quality of the cabinet. The components of the universal cabinet are designed according to the module principle, and there are 20-module mounting holes, with a high universality coefficient. This enables the company to realize pre-production, which not only shortens the production and manufacturing cycle but also improves work efficiency.
2、During the design of GGD cabinets, full consideration is given to the heat dissipation issue during the operation of the cabinet. There are different numbers of heat dissipation slots at both the upper and lower ends of the cabinet. When the electrical components inside the cabinet generate heat, the heat rises and is discharged through the upper slots, while cold air continuously enters the cabinet through the lower slots. This creates a natural ventilation channel from bottom to top in the sealed cabinet, achieving the purpose of heat dissipation.
3
、In line with modern industrial product design requirements, the GGD cabinet’s overall appearance and component division dimensions are designed using the golden ratio, resulting in an elegant and aesthetically pleasing cabinet.
4

、The cabinet door is connected to the frame via rotating movable hinges, facilitating easy installation and disassembly. A mountain-shaped sealing strip is embedded in the door’s folded edge. When the door is closed, the sealing strip between the door and the frame undergoes a certain compression stroke, preventing direct collision between the door and the cabinet while improving the door’s protection class.
5、The instrument door equipped with electrical components is connected to the frame using multi-strand flexible copper wires. Mounting parts inside the cabinet are connected to the frame with knurled washers, forming a complete grounding protection system for the entire cabinet.
6、The cabinet surface is treated with a high-voltage electrostatic spraying process, featuring strong adhesion and a premium texture. The entire cabinet has a matte finish, avoiding glare and creating a comfortable visual environment for on-duty personnel.
7、The cabinet’s top cover can be removed when necessary to facilitate on-site assembly and adjustment of the main busbars. Lifting rings are installed at the four corners of the cabinet top for hoisting and transportation.
8、The cabinet’s protection class is IP30. Users can also select a protection class between IP20 and IP40 according to the requirements of the operating environment.

VI. Installation and Usage
When the product arrives at the receiving locations, first, check whether the packaging is intact. If any problem is found, promptly notify the relevant departments to investigate the cause. For products that will not be installed immediately, they should be placed in an appropriate place in accordance with the regulations for normal use conditions.
1

、Product Installation

The installation of the product shall be carried out in accordance with the installation diagram. Foundation channel steel and bolts shall be provided by the user. During the installation of the main busbar, the contact surfaces shall be smoothed, cleaned thoroughly, and coated with neutral Vaseline or treated with other appropriate measures, followed by secure bolt tightening.

2

、After the product is installed and before it is put into operation, the following items of inspection and testing need to be carried out.

A. Check for paint peeling on the cabinet surface and ensure the interior of the cabinet is dry and clean.
B. Verify that the operating mechanisms of electrical components are flexible, with no jamming or excessive operating force.
C. Confirm that the switching of main electrical components is reliable and accurate, as well as the switching of auxiliary contacts.
D. Ensure that instrument indications, transformer ratioses, and polarities are correct.
E. Check that busbar connections are in good condition, and that insulation supports, mounting parts, and accessories are firmly and reliably installed.
F. Verify that auxiliary contacts meet requirements, fuse element specifications are correct, circuit breaker settings comply with design requirements, and their actions are accurate.
G. Confirm that circuit connections conform to the requirements of the electrical schematic diagram.
H. Ensure that the protection circuit system meets requirements.
I. Measure the insulation resistance with a 500V megohmmeter; the resistance shall not be less than 1MΩ.

3、Operational Precautions

A. This product is a freestanding low-voltage distribution cabinet designed for single-sided (or double-sided) operation and double-sided maintenance. Only qualified professional personnel are permitted to access the maintenance aisle or open the cabinet door for operation, inspection, and maintenance.
B. After multiple closing and opening operations, the main contacts of the air circuit breaker may suffer local burns and carbon deposition, leading to increased contact resistance. Regular maintenance and inspection of the air circuit breaker shall be performed in accordance with its user manual.

VII. Product Completeness

The manufacturer shall supply the following parts and accessories with the product:

a. Packing List
b. Product Certificate of Conformity
c. User Manual
d. Factory Test Report
e. Relevant Electrical Drawings
f. Cabinet Door Keys, Operating Handles, and Spare Parts Specified in the Contract
VIII. Ordering Instructions
Users should provide the following information when placing an order:
1

、All models of the product (including the main circuit scheme number and the auxiliary circuit scheme number).
2、Combination sequence diagram of the main circuit system.
3
、Electrical Schematic Diagram of the Auxiliary Circuit.
4

、List of components inside the cabinet.
5
、Other special requirements that are inconsistent with the normal usage conditions of the product.