Energy Efficient Metal Enclosed Switchgear

I. Product Overview

The XGN15-12 (F)/XGN15-12 (F·R) series of box-type fixed AC metal-enclosed switchgear (commonly known as "ring main units") is a new generation of indoor core power distribution equipment developed specifically for 10kV/12kV medium-voltage distribution networks. The product uses an SF₆ gas-insulated load switch as its core component. The F type is a pure load switch unit, while the F·R type integrates a load switch with a high-breaking capacity fuse to form a "switch-fuse" combined protection unit.

This series of products adopts a composite insulation structure of air insulation + SF₆ gas tank sealing, and 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 Equipment" and IEC 62271-200 "High-Voltage Switchgear and Control Equipment - Part 200: Metal-Enclosed Switchgear and Control Equipment". Its core advantages lie in its ultra-compact structure, high safety level, long maintenance-free period, and wide adaptability to scenarios. It is widely used in urban distribution network ring network power supply, industrial and mining enterprise terminal power distribution, pre-installed substation (box-type substation) high-voltage side, public facility power distribution systems and other scenarios. It is a key equipment for realizing distribution network automation and improving power supply reliability.

II. Core Structure and Working Principle

(1) Core Structural Composition

This product adopts a modular, front maintenance design, and the overall structure consists of the following core components:

SF₆ sealed gas tank:

Made of 3mm thick stainless steel through laser welding, the welds are inspected by helium mass spectrometry to ensure permanent sealing, and no gas replenishment is required during the service life.

It is filled with SF₆ gas at a gauge pressure of 0.045MPa, which serves as the insulation and arc-extinguishing medium for the load switch.

A built-in three-position (closing/opening/grounding) load switch integrates the functions of an isolation switch and a grounding switch.

High-voltage main circuit:

Composed of moving and static contacts inside the gas tank, as well as external high-voltage bushings and busbars, connected by tinned copper bars, with low contact resistance and strong current-carrying capacity.

The F·R type is equipped with a high-breaking capacity current-limiting fuse, installed outside the gas tank, and connected to the load switch through a mechanical linkage device.

Operation and interlocking mechanism:

Adopts a manual spring operating mechanism, with an optional electric operating mechanism, featuring small operating torque and reliable opening and closing.

Equipped with a complete mechanical interlock, strictly implementing the "five preventions" function, namely preventing erroneous opening and closing, preventing opening and closing under load, preventing hanging ground wires with electricity, preventing closing with ground wires, and preventing entering live intervals by mistake.

Cabinet and protection:

Adopts aluminum-zinc coated steel plate or 304 stainless steel for integral bending forming, with the surface treated by electrostatic spraying for corrosion and rust resistance.

The cabinet has a front-opening design, and all maintenance operations can be completed from the front without reserving maintenance space on the sides and rear.

The top is equipped with a directional pressure release channel, which can guide high-temperature and high-pressure gas to a safe direction in case of internal arc faults, preventing the cabinet from exploding.

(2) Working Principle

Normal operation: The load switch is in the closing position, supplying power to downstream loads.

Opening operation: When power outage maintenance is required, the operating mechanism opens the load switch to cut off the load current.

Grounding operation: After confirming that the line is de-energized, switch the switch to the grounding position and connect the grounding wire to ensure the safety of maintenance personnel.

Fault protection (F·R type): When a transformer has a short circuit or overload, the fuse quickly blows, triggering the load switch to automatically open through the mechanical linkage device, cutting off the fault circuit and protecting the transformer and power grid.

III. Specification Parameters (Full-Dimensional Coverage，customizable)

Table

Parameter Category

Core Specifications

Detailed Description

Rated voltage

12kV

Adapts to China's 10kV distribution network standard

Rated frequency

50Hz

Conforms to the power frequency grid standard

Rated current

630A

Main circuit rated current, meeting general power distribution needs

Rated short-circuit breaking current

20kA (2s)

Can withstand a short-circuit current impact of 20kA for 2 seconds

Rated lightning impulse withstand voltage

75kV

Protects equipment from lightning overvoltage damage

Main switch type

SF₆ three-position load switch

Integrates closing, opening, and grounding functions, no additional configuration required

Fuse (F·R type)

High-breaking capacity current-limiting fuse

Rated current 100A-200A, can protect transformers of 1600kVA and below

Insulation medium

SF₆ inside the gas tank, external air

Composite insulation, considering both reliability and environmental protection

Protection class

IP30 (internal) / IP65 (gas tank)

Prevents finger contact with live parts, the gas tank is completely dustproof and waterproof

Cabinet material

Aluminum-zinc coated steel plate / 304 stainless steel

Corrosion and rust resistance, suitable for indoor / outdoor (inside box-type substation) use

Single cabinet width

375mm / 500mm

Ultra-compact design, greatly saving power distribution room space

Mechanical life

≥10000 times

Long switch operation life, long maintenance-free period

Working environment

Temperature: -25℃～+40℃; Humidity: ≤95% (no condensation); Altitude: ≤2000m (high altitude can be customized)

Adapts to most indoor environments, insulation enhancement can be customized for high-altitude areas

IV. Core Product Advantages

(1) Safe and reliable, risk controllable

Fully sealed gas tank: The stainless steel gas tank adopts laser welding and helium mass spectrometry leak detection technology to ensure zero leakage of SF₆ gas, the insulation performance is not affected by the external environment, and the operation is safe and stable.

Complete "five preventions" interlock: Double protection of mechanical interlock and electrical interlock fundamentally eliminates personal and equipment accidents caused by misoperation.

Arc fault protection: Built-in directional pressure release channel can effectively relieve pressure in case of internal arc faults, ensuring the safety of operation and maintenance personnel and equipment.

Precise protection (F·R type): The combination of load switch and high-breaking fuse can quickly cut off the power supply when the transformer fails, protecting the transformer from damage.

(2) Compact structure, space efficient

Ultra-compact modularization: The width of a single cabinet is only 375mm, saving about 30% of the floor area compared with traditional switch cabinets, especially suitable for power distribution rooms and box-type substations with limited space.

Three-position integration: The load switch integrates three positions of opening, closing, and grounding, simplifying the cabinet structure, reducing fault points, and improving overall reliability.

Front maintenance design: All operations and maintenance can be completed on the front of the cabinet without reserving maintenance space on the sides and rear, greatly improving space utilization.

(3) Convenient operation and maintenance, low cost

Maintenance-free design: The SF₆ gas tank has a permanently sealed structure, the switch has a long mechanical life, and no regular maintenance is required under normal operation, significantly reducing operation and maintenance costs.

Visual monitoring: The cabinet is equipped with an observation window, which can directly check the switch position and fuse status, and the operation status is clear at a glance.

Intelligent operation and maintenance optional: Can be configured with an intelligent online monitoring module to realize remote monitoring, fault alarm, and remote operation, helping to realize the "unattended" intelligent distribution network.

(4) Strong adaptability, wide scenarios

Flexible combination: Can be freely combined into various functional units such as incoming line, outgoing line, metering, PT, and interconnection to meet the needs of different power distribution networks.

Full scenario coverage: Widely used in urban distribution networks, industrial and mining enterprises, commercial buildings, hospitals, schools, pre-installed substations and other scenarios.

Good compatibility: Can be seamlessly connected with mainstream protection relays and automation systems at home and abroad, making it easy to realize the automation upgrade of the distribution network.

V. Typical Application Scenarios

Urban distribution network transformation: As a ring network power supply unit, it realizes "hand-in-hand" power supply, improves power supply reliability, and reduces the scope of power outages.

Industrial and mining enterprise power distribution: Used for terminal power distribution in factories, mines and other places to protect important production equipment such as motors and fans.

Pre-installed substation (box-type substation): As the high-voltage switch unit inside the box-type substation, it cooperates with transformers and low-voltage cabinets to form a complete power distribution solution.

Public facilities: Applied to shopping malls, airports, subways, hospitals and other places with extremely high requirements for power supply reliability.

New energy access: As the grid-connection switch equipment for new energy power stations such as photovoltaic and wind power, it ensures the safe and stable transmission of new energy power.