enclosed switchgear

  XGN2-12(Z) 12kV Indoor Box-type Fixed AC Metal-enclosed Switchgear Product Manual

   1. Product Overview

XGN2-12 (Z) is a 12kV indoor box-type fixed AC metal-enclosed switchgear, a classic fixed switchgear model widely used in the medium-voltage power distribution field in China. With a vacuum circuit breaker as the core breaking component, it adopts a metal armored, compartment-sealed and fixed installation structure. It is designed and manufactured in strict accordance with national and international standards such as GB 3906 "3.6kV～40.5kV AC Metal-enclosed Switchgear and Control Gear" and IEC 60298 "AC Metal-enclosed Switchgear and Control Gear for Rated Voltages Above 1kV and Below 52kV". It features core advantages such as safety and reliability, high breaking capacity, convenient maintenance and good expandability, making it an ideal power distribution equipment for traditional distribution networks, industrial power supply and small substations.

This product is mainly used for power distribution, control and protection of 10kV distribution networks. It can realize functions such as line switching, fault isolation and voltage monitoring. It is widely adapted to scenarios such as urban distribution stations, industrial and mining enterprises, auxiliary power supply of power plants, rail transit power supply and new energy grid connection, and is especially suitable for working conditions with high reliability requirements and frequent operation needs.

   2. Core Structure and Working Principle

    2.1 Core Structure Composition

The product adopts a modular compartment design and front and rear maintenance structure, and is composed of four independent compartments and supporting components as a whole:

1.   Cabinet Frame and Protection  

    (1) The cabinet is formed by CNC bending and welding of high-strength cold-rolled steel sheet/aluminum-zinc coated sheet with a thickness of 2.0~2.5mm. The surface is treated with phosphating rust removal + electrostatic spraying, which is anti-corrosion, rust-proof, high in mechanical strength and has an seismic resistance of Grade 8, adapting to complex terrain and vibration environments.

    (2) The cabinet is divided into four independent metal compartments: circuit breaker compartment, busbar compartment, cable compartment and relay compartment. Each compartment is completely isolated by grounded metal partitions, which effectively blocks the spread of fault arcs and high-temperature gas and prevents fault expansion.

    (3) The front and rear double-door design supports wall-mounted installation. Maintenance operations of all primary and secondary components can be completed on the front/back side without reserving side maintenance space, which greatly improves the space utilization rate of the power distribution room.

    (4) Oriented pressure relief channels are set on the top and each compartment. When an arc fault occurs inside, high-temperature and high-pressure gas can be quickly directed to a safe direction to prevent the cabinet from bursting and ensure the safety of operation and maintenance personnel and surrounding equipment.

2.   Core Components of Primary Main Circuit  

    (1) Vacuum circuit breaker: Standard with ZN28, ZN63 (VS1) and other series of vacuum circuit breakers, optional permanent magnet/spring operating mechanism, rated current covering 630A~3150A, rated short-circuit breaking current up to 20kA~40kA, mechanical life ≥10,000 times. It has the advantages of fast breaking speed, strong arc extinguishing ability and maintenance-free, and can frequently switch load and short-circuit current.

    (2) Isolating switch/earthing switch: Installed with the circuit breaker, adopts manual operating mechanism to realize electrical isolation and safe earthing. It forms mandatory interlock with the circuit breaker and cabinet door through mechanical interlock, strictly implementing the "five prevention" functions.

    (3) Busbar system: Adopts tinned copper busbar/aluminum busbar, with sufficient insulation distance between phases and to ground, creepage distance ≥25mm/kV. Double busbar or single busbar with bypass structure can be customized to meet different power distribution network requirements; the busbar compartment adopts a sealed design to prevent dust and moisture intrusion and ensure long-term insulation stability.

    (4) Cable connection components: The cable compartment has ample space, can adapt to high-voltage cables with a cross-sectional area of 3×300mm² and below, and is equipped with cable clamps, earthing terminals and current transformers for convenient cable installation, earthing and current monitoring.

3.   Secondary Control and Interlock System  

    (1) "Five prevention" mechanical interlock: Realize mandatory interlock through mechanical structures such as connecting rods and latches to ensure:

        ① Prevent closing/opening isolating switch under load;

        ② Prevent incorrect closing/opening of vacuum circuit breaker;

        ③ Prevent connecting earthing wire/ closing earthing switch with power on;

        ④ Prevent closing with earthing wire/earthing switch closed;

        ⑤ Prevent entering live compartment by mistake.

    (2) Secondary relay compartment: Integrates protection relays, ammeters, voltmeters, indicator lights and operation buttons. It can be configured with protection functions such as overcurrent, instantaneous trip, zero-sequence and overvoltage, and supports connection with integrated protection devices and automation systems.

    (3) Operating mechanism: The circuit breaker adopts a spring operating mechanism, which can be operated manually/electrically with small operating torque and reliable closing and opening; the isolating switch/earthing switch adopts manual operation and is equipped with position indicators to visually display equipment status.

    2.2 Working Principle

- Normal operation: The vacuum circuit breaker is closed, the isolating switch is in the closed position, and current is distributed through busbar→circuit breaker→cable→downstream load; the secondary system monitors operating parameters such as current and voltage in real time.

- Opening operation: Trigger the circuit breaker to open manually or electrically to cut off the load current; for maintenance, disconnect the isolating switch and close the earthing switch to realize electrical isolation and safe earthing of the line.

- Fault protection: When a short circuit, overload and other faults occur on the line, the protection relay acts to trigger the circuit breaker to open quickly, cut off the fault circuit and avoid fault expansion; after fault elimination, manual reset can be performed to restore power supply.

   3. Core Specifications (Full Coverage，customizable)

| Parameter Category | Core Specifications | Detailed Description |

|--------------------|---------------------|----------------------|

| Rated Voltage | 12kV | Adapted to China's 10kV distribution network standard |

| Rated Frequency | 50Hz | In line with power frequency grid standard |

| Rated Current | 630A / 1250A / 1600A / 2000A / 3150A | Covering all scenarios from small-scale distribution to large-scale industrial loads |

| Rated Short-circuit Breaking Current | 20kA / 25kA / 31.5kA / 40kA (3s) | Vacuum circuit breakers with different breaking capacities can be selected according to requirements |

| Rated Peak Withstand Current | 50kA / 63kA / 80kA / 100kA | Corresponding to the peak withstand capacity of short-circuit breaking current |

| Main Switch Type | Vacuum Circuit Breaker | Optional ZN28, ZN63 (VS1) and other models, spring/permanent magnet mechanism |

| Insulation Level | Power Frequency Withstand Voltage: 42kV/1min; Lightning Impulse Withstand Voltage: 75kV | In line with GB 311 standard to ensure insulation reliability |

| Protection Grade | IP30 (Cabinet) / IP67 (Circuit Breaker Terminal) | Prevent fingers from touching live parts; dustproof and waterproof for circuit breaker terminal |

| Cabinet Dimensions | Height: 2200~2300mm; Width: 1000~1200mm; Depth: 1200~1500mm | Customizable size according to configuration |

| Mechanical Life | Circuit Breaker: ≥10,000 times; Isolating Switch: ≥5,000 times | Long service life of core components and long maintenance-free cycle |

| Working Environment | Temperature: -25℃～+40℃; Humidity: ≤95% (no condensation); Altitude: ≤2000m (customizable for high altitude) | Adapt to most indoor environments; enhanced insulation for high altitude areas |

| Implementation Standards | GB 3906, IEC 60298, GB 311, DL/T 404 | Fully comply with national, industrial and international standards |

   4. Core Product Advantages

    4.1 Ultimate Safety Protection and Controllable Operation Risk

1. Complete "five prevention" interlock: Mechanical mandatory interlock eliminates personal and equipment accidents caused by human misoperation at the source.

2. Arc fault protection: Compartment isolation + directional pressure relief channel effectively curb fault spread and ensure the safety of operation and maintenance personnel.

3. Excellent insulation performance: Increased creepage distance and sufficient insulation spacing adapt to harsh environments such as high humidity and pollution, with stable and reliable insulation.

4. Metal enclosed structure: Fully metal shell earthing prevents electric shock and external environmental interference, ensuring safer operation.

    4.2 Strong Performance and Adaptability to Complex Working Conditions

1. High breaking capacity and large current: The vacuum circuit breaker has strong breaking capacity, meeting the requirements of large current scenarios such as large substations and industrial loads.

2. Adaptability to frequent operation: The circuit breaker has a long mechanical life, suitable for industries requiring frequent switching such as iron and steel and chemical industry.

3. Flexible busbar configuration: Support single busbar, double busbar, single busbar with bypass and other structures, adapting to various power distribution networks.

4. Full working condition compatibility: Can operate stably in environments such as -25℃~+40℃, high altitude and high humidity without special environmental restrictions.

    4.3 Convenient Maintenance and Low Life-cycle Cost

1. Compartment maintenance design: Each compartment is independent, can be repaired in partitions without affecting the operation of other circuits.

2. Double-sided maintenance layout: Front and rear doors, wall-mounted installation, no side maintenance space required, high space utilization rate.

3. Maintenance-free core components: The vacuum circuit breaker arc extinguishing chamber is maintenance-free, and the overall structure has no vulnerable parts, with low maintenance cost.

4. Visual monitoring: Equipped with position indicators and instrument windows to visually check equipment status and facilitate daily inspection.

    4.4 Intelligent Expansion for the Future

1. Intelligent upgrading: Can integrate temperature sensing monitoring, arc protection, online monitoring modules to realize equipment state perception.

2. Automation docking: Support communication protocols such as Modbus and IEC 61850, and can be seamlessly connected to distribution network automation systems.

3. Compatibility with various protection devices: Can cooperate with mainstream integrated protection devices and measurement and control devices at home and abroad to meet the needs of smart grids.

   5. Typical Application Scenarios

1. Urban distribution network: As incoming, outgoing and sectionalizing switches of 10kV distribution stations to realize power distribution and fault isolation.

2. Industrial and mining enterprises: Used for power distribution in factories, mines, metallurgy and other industries to protect important loads such as motors and fans.

3. Auxiliary power supply of power plants: As switchgear for auxiliary power supply of power plants to ensure reliable power supply for auxiliary systems of generator sets.

4. Rail transit: Used for traction power supply systems of subways, light rails and other rail transit to provide stable and reliable power distribution guarantee.

5. New energy grid connection: As grid-connected switchgear for photovoltaic, wind power and other new energy power stations to realize safe transmission of new energy power.

6. Infrastructure: Applied to places with high power supply reliability requirements such as airports, hospitals and data centers.