Box-type fixed AC metal-enclosed switchgear

Product Introduction

The XGN15-12 unit-type AC metal-enclosed ring main switchgear (hereinafter referred to as the ring main unit) is a new high-voltage electrical product independently designed and developed by us, based on the introduction of advanced foreign technology and in accordance with the requirements of domestic rural power and urban network upgrades. All technical performance indicators fully comply with IEC62271-200:2003 and GB3906 standards.
The main switch, operating mechanism, and components of the ring main unit adopt ABB's original parts or the SFL-12/24 switchgear assembled domestically with imported components. It can also be equipped with ABB's original HAD/US type SF6 circuit breaker or VD4-S type vacuum circuit breaker according to user requirements. The operation methods include manual and electric.
The cabinet is riveted after processing by CNC machine tools, with a protection level of IP3X, and features reliable mechanical interlocking and anti-misoperation functions. This product is characterized by its small size, light weight, attractive appearance, simple operation, long lifespan, high parameters, no pollution, and minimal maintenance.
The XGN15-12 unit-type AC metal-enclosed ring main switchgear is suitable for use in 50Hz, 12kV power networks for the reception and distribution of electrical energy. The main switch inside the cabinet is an SF6 switch.

Model Meaning

Main Technical Parameters of Vacuum Circuit Breaker

Structural Features

Cabinet Structure
◆ The ring main unit cabinet is riveted from 2mm thick aluminum-zinc coated steel plate (or cold-rolled plate after spray painting). There are two pressure release holes at the rear of the cabinet, one for the cable compartment and another for the load switch/busbar compartment. This structure maximizes the safety of personnel and the reliability of operating equipment.
◆ Each compartment ◇ Busbar Compartment
The busbar compartment is located at the top of the cabinet and connects adjacent switchgear.
◇ The load switch is an independent unit, filled with SF6 gas.
◇ Cable Compartment
Approximately 75% of the space is used for cable connections, fuses, grounding switches, and CT/PT installation.
◇ Mechanism Compartment and Interlocking
This compartment contains the operating mechanism, mechanical interlocks, position indicators, auxiliary contacts, trip coils, voltage indicators, and interlocks.
◇ Relay Box
The relay box is located at the top of the cabinet and is optional. It is used to install special devices such as meters, relays, and motor units.
◇ Circuit Breaker Compartment
A circuit breaker (SF6 or vacuum) can be installed below the load switch.
◆ Pressure Release
◇ Upper Pressure Release
The upper release is used to vent gas pressure generated during internal arc faults in the busbar and load switch compartments.
◇ Lower Pressure Release
The lower release is used to vent gas pressure generated during internal arc faults in the cable compartment. ◆ SFL Type Load Switch (ABB Original Part)
The SFL type load switch features double-break, rotating moving contacts, with SF6 gas as the arc-extinguishing medium. The moving and fixed contacts are housed in a reinforced molded epoxy resin enclosure. At the operating shaft outlet, there is a transparent heat-formed plastic end cover, allowing visual status inspection.
Each switch is permanently sealed after being filled with SF6 gas at 1.4 bar pressure (SFL means "Sealed For Life"). Gas leakage can be checked using a helium detector. The switch can be installed vertically or horizontally. In unit-type cabinets, the typical installation is horizontal, with a steel partition between the cable compartment and the busbar compartment.
This installation method encloses the switch housing in grounded steel plates and isolates the busbar from cable connections, meeting the strictest safety requirements for operation and maintenance.
In the event of an internal arc, a structurally weak point at the rear of the housing will burst open, directing arc gases out of the switch. Subsequently, the arc venting flap at the top of the cabinet will open, guiding the overpressure gases outside the cabinet.

Interlocking

The switchgear is equipped with the following interlocks:
1. When the load switch is in the closed position, the grounding switch operation is locked; 2. When the grounding switch is in the closed position, the load switch operation is locked;
3. The front door of the ring main unit can only be opened when the grounding switch is closed; in all other cases, the front door is locked.

Operation

For switchgear equipped with a load switch, operation is performed using a dedicated operating handle on the front of the switchgear. The operating mechanism has two operation holes on the front: the upper one for the grounding switch and the lower one for the load switch. During operation, rotating the handle clockwise closes the switch, while counterclockwise rotation opens it. An electric opening/closing device can also be added for remote control. (Note: Sometimes the load switch does not include a grounding switch; the grounding switch operation hole is then used for cabinet door unlocking.)
For switchgear equipped with a combined apparatus, the operation sequence is the same as above, except that the load switch opening operation is performed using a manual opening button. The combined apparatus cabinet has an additional lower grounding switch, which operates simultaneously with the upper grounding switch via a linkage. When closing, it releases residual small currents on the lower fuse base to improve safety during fuse replacement.

Outline Dimensions