High‑voltage Central‑mounted Switchgear_High‑Voltage Complete Switchgear_Product

Product Overview

HXGN‑12/24 Type Box‑type Fixed Fully‑enclosed Switchgear is our self‑developed three‑phase AC 50 Hz vacuum load‑break switchgear with rated voltage 12/24 kV, also referred to as vacuum ring main unit. It is suitable for ring‑network power supply of 10/24 kV systems, as well as power supply and distribution systems in industrial‑mining enterprises, high‑rise buildings, residential quarters, etc. The main switch adopts vacuum arc‑extinguishing principle, featuring high breaking capacity and reliable performance, especially suitable for frequent‑operation scenarios.

The vacuum ring main unit consists of two cabinet types: vacuum load‑break switch cabinet and vacuum load‑break switch‑fuse combination unit cabinet. Both vacuum load‑break switch and vacuum load‑break switch‑fuse combination unit adopt vacuum arc‑extinguishing principle. Moving and fixed contacts are enclosed inside vacuum interrupters. During breaking, metal vapor diffuses rapidly to extinguish vacuum arc at zero‑crossing point of power supply. Its dielectric strength recovers much faster than air, hence excellent breaking performance and high operational reliability. The transfer current of air load‑break switch (gas‑producing or gas‑pressure type) combination unit is generally only around 1000 A, while the transfer current of vacuum load‑break switch‑fuse combination unit can reach 3150 A (higher values available), delivering superior operational safety and reliability.

This product complies with relevant provisions of IEC298, GB3906, GB3804 and other standards.

Technical Parameters

Project Name	Unit	Load‑break Switch	Fuse‑combination Unit
Rated Voltage	kV	12(24)
Rated Frequency	Hz	50
Rated Current	A	630,	125
4 s Thermal‑Stable Current (RMS)	kA	20	31.5
Rated Dynamic‑Stable Current (Peak Value)	kA	50	80
1 min Rated Power‑Frequency Withstand Voltage	kV	42 (65) Between Poles
1 min Rated Power‑Frequency Withstand Voltage	kV	48 (79) Across Breaking Contacts
Lightning Impulse Withstand Voltage	kV	75 (125) Between Poles
Lightning Impulse Withstand Voltage	kV	85 (145) Across Breaking Contacts
Protection Rating		IP3X

* All products are custom‑made, and parameters are for reference only.

Normal Use Condition

Ambient temperature: ‑35°C ~ 45°C

Altitude: ≤1000 m

Relative humidity: daily average ≤95%, monthly average ≤90%

Seismic intensity: ≤Grade 8

Service location: Indoor, free of fire and explosion hazards, severe pollution and chemical corrosion.

Note: Special written instructions shall be submitted upon order if the above normal service environmental conditions are exceeded.

This product can be designed to connect to computer interfaces to realize on‑line centralized monitoring and control of power system.

Product Features

The ring main unit is assembled with 8MF profiles, and the full‑frame mounting modular holes have a pitch E=20 mm.

Lead‑seal pins are fitted on the door and instrument door of the metering cabinet. The fuse‑combination unit cabinet is equipped with striker‑pin fitted fuse links. Under short‑circuit conditions, the striker pin strikes the tripping mechanism to realize rapid breaking for effective protection of electrical equipment.

The ring main unit is internally equipped with FZN21‑12D or FZN25‑12 vacuum load‑break switch, which is integrated with disconnector, vacuum load‑break switch and earthing switch. Both the disconnector and earthing switch feature visible isolating gaps.

Complete and reliable mechanical linkage and interlock devices are provided for the disconnector, vacuum load‑break switch, earthing switch and cabinet door to effectively prevent mis‑operation and guarantee safe maintenance. Both manual and electric operations are available.

The ring main unit is front‑operated and can be wall‑mounted.

Five‑prevention interlock function--Power‑on operation: The load‑break switch can only be closed after the cabinet door is closed and locked, and the earthing switch is switched to the OPEN position. Power‑off operation: The earthing switch can only be closed when the load‑break switch is at the isolated position. When the earthing switch is closed, the insulating partition shall be fully inserted before the cabinet door can be opened. Reliable interlock exists between vacuum interrupter and isolating knife; the isolating knife and earthing knife are mutually linked, and interlocked with cabinet door. The insulating partition is also interlocked with the cabinet door.