Rated voltage: 12kV or 24kV (marked as 12~24 means that the series covers these two voltage levels, but 12kV is the most widely used).
Rated current: Common ones are 630A, 1250A, etc.
Rated frequency: 50Hz.
Rated short-circuit breaking current: Load switch cabinet is usually 20kA or 25kA (effective value).
Rated short-circuit closing current: Usually 50kA or 63kA (peak value).
Rated short-time withstand current: Usually 20kA or 25kA (effective value), duration 3s or 4s.
Rated peak withstand current: Usually 50kA or 63kA (peak value).
Rated insulation level:
1min power frequency withstand voltage: 42kV to ground and phase-to-phase (12kV cabinet), 65kV or 70kV (24kV cabinet); 48kV (12kV cabinet), 79kV (24kV cabinet) at isolating break.
Lightning impulse withstand voltage: 75kV to ground and phase-to-phase (12kV cabinet), 125kV (24kV cabinet); 85kV (12kV cabinet), 145kV (24kV cabinet) at isolating break.
Main circuit resistance: ≤ standard value (the specific value depends on the rated current and design, usually in micro-ohm level).
Protection level: The outer shell usually reaches IP3X or IP4X; the internal compartment reaches IP2X; the high-voltage fuse barrel reaches IP6X.

Fixed installation: All main components (load switch, grounding switch, fuse, busbar, cable connector, etc.) are fixedly installed in their respective compartments. Maintenance or overhaul requires power off, which is the biggest difference from the removable (handcart) switch cabinet.

SF6 gas insulation:

The core switch component (usually a three-position load switch) is installed in a sealed stainless steel or high-quality aluminum-zinc plate welded gas box.

The gas box is filled with SF6 gas at a slight positive pressure (0.04~0.05 MPa) as an insulating and arc-extinguishing medium.

Advantages: Small size, excellent insulation performance, not affected by the external environment (such as dirt, condensation), safe and reliable, maintenance-free (under good gas box sealing).

Three-position load switch:

Core component! It integrates the three functions of isolation, connection (closing), and grounding in one switch body, which are realized through a set of operating mechanisms.

Clear workstations: With three distinct positions of "on-off-off-grounding".

Reliable operation: Spring energy storage operating mechanism, fast opening and closing speed, stable performance.

Reliable interlocking: There is a forced mechanical interlock between the three workstations to prevent misoperation (such as preventing the disconnector from opening and closing with load, preventing the grounding switch from closing with power on, and preventing the grounding switch from closing when it is closed).

Modular design:

The basic units (such as incoming line unit, outgoing line unit, metering unit, PT unit, contact unit, etc.) have similar structures and are easy to combine and expand.

The main busbar is connected through the busbar connector between the cabinets to form a ring network power supply system.

Compartment division:

Main busbar room: Located at the upper back or top of the cabinet, it runs through all cabinets.

SF6 gas tank (switch room): The core part, including three-position switches and possible fuses.

Cable room: Located at the bottom of the cabinet, used for the connection of incoming and outgoing cables (usually with live display, lightning arrester, etc.).

Low voltage room/mechanism room: Located at the front or lower side of the cabinet, it is used to install operating mechanisms, control protection components (relays, instruments, terminal blocks, DTU, etc.), and secondary wiring.

Instrument room (optional): Located at the upper front of the cabinet, it is used to install instruments, indicators, etc.

Each compartment is separated by a metal partition to improve safety.

Fuse combination electrical solution:

Outgoing cabinets often use a combination of "load switch + high-voltage current limiting fuse" (i.e. "-F" circuit).

Fuses are used for short-circuit protection of load equipment such as transformers, and load switches are used for opening and closing normal currents and providing obvious isolation breaks.

The fuse is usually installed in or under the gas box, and has a striker-linked tripping mechanism with the switch (the fuse triggers the load switch to open when it melts).

Safety features:

"Five-protection" interlocking: Forced mechanical interlocking ensures safe operation (preventing accidental opening and closing of circuit breakers/switches, preventing opening and closing of isolating switches with load, preventing closing of grounding switches with power on, preventing power supply when the grounding switch is closed, and preventing accidental entry into live intervals).

Pressure relief channel: A pressure relief device (such as a bursting disc) is designed on the top of the gas box. When a serious fault occurs inside and overpressure occurs, the pressure can be released in a directional manner to protect the safety of the operator.

Observation window: An observation window is usually provided on the front door panel or mechanism panel to observe the switch position indication and energy storage status indication.

Reliable grounding: The cabinet is equipped with a main grounding bar, and the metal parts of each compartment are reliably grounded.

Operating mechanism:

Spring energy storage operating mechanism (manual or electric) is usually used.

Manual operation: Energy storage and opening and closing operations are performed through the operating handle (front door panel or side), the operating force is moderate, and there is a clear "click" sound to indicate that the energy storage is completed.

Electric operation (optional): Equipped with motor-driven energy storage, remote opening and closing operations can be realized (commonly used in places with high automation requirements).

Position indication: Clear switch position (on/off/grounding) indication and energy storage status indication.

Expandability and application:

Easy to form a ring network power supply system (N units).

Applicable to terminal distribution stations (such as box transformers, industrial and mining enterprises, communities, commercial centers, public facilities, etc.).

Distribution automation functions (telemetry, telesignaling, remote control, fault detection/location/isolation) can be realized by adding DTU/FTU.

Line entry mode: both upper and lower lines are available.

Installation mode:

Mainly suitable for indoor installation.

It can also be used in semi-outdoor (such as in box-type substations) under the condition of meeting the protection and operating environment requirements (such as installing rain covers and controlling environmental temperature and humidity).

In summary, the core advantages of HXGN-12~24 fixed ring network cabinets are:

Compact structure and small footprint.

SF6 gas insulation, reliable performance, and long maintenance-free cycle.

Three-position switch has high integration, simple operation, and reliable interlocking.

Modular design, flexible combination, and easy expansion.

High safety (five-protection interlocking, pressure relief channel).

Mature technology and relatively economical cost.