Ring Main Unit

HXGN-40.5 Box-Type Ring Main Unit

HXGN-40.5 is indoor, metal-enclosed ring main switchgear for 35 kV-class distribution networks. Its box-type assembly is available in two configurations: HXGN-40.5(F) with a load switch, and HXGN-40.5(F.R) with a load-switch–fuse combination for circuits requiring fuse protection.

The F configuration provides 400 A active-load breaking capacity and a short-time withstand rating of 16 kA for 3 seconds. The F.R fuse combination has a rated short-circuit breaking capacity of 31.5 kA. These distinct duties allow the configuration to be matched to the circuit's switching and protection requirements.

Technical Specifications

Rated Voltage	40.5 kV
Rated Frequency	50 Hz
Active-Load Breaking Current (F)	400 A
Cable-Charging Breaking Current (F)	21 A
Short-Time Withstand Current (F)	16 kA / 3 s
Peak Withstand Current (F)	40 kA
Fuse-Combination Short-Circuit Breaking / Making (F.R)	31.5 / 80 kA
Power-Frequency Withstand Voltage	95 kV / 1 min
Lightning Impulse Withstand Voltage	185 kV
Switching Units	F: load switch; F.R: switch-fuse

Key Features

HXGN-40.5(F) load-switch configuration.
HXGN-40.5(F.R) fuse-combination configuration.
16 kA / 3 s short-time withstand for the F configuration.
Metal-enclosed construction for 35 kV-class secondary distribution.

Typical Applications

Wind farms
Industrial and mining-site substations
Large buildings with a 35 kV supply

Installation & Aftercare

Prepare the site, plan routine checks and keep service records.

What needs to be ready before installation?

Provide an indoor foundation and aisle arrangement suitable for operating handles, door travel and cable termination work.
For F.R units, retain access to remove the specified fuse assembly during isolation; coordinate cable bending and earthing space.
Keep the switchroom dry and ventilated, with electrical and pressure-relief clearances taken from the supplied assembly drawings.

What should operators check during routine rounds?

During rounds, inspect external indications and room conditions, and record switching events or fuse operation.

What is covered during planned maintenance?

At scheduled isolation, qualified personnel check switch mechanisms, interlocks, fuse contacts, insulation and earthing connections.
Investigate abnormal heating or a blown fuse before returning the branch to service; replacement fuses must match the coordinated protection design.

Customization Options

Define the electrical configuration and the details needed for your site.

Network arrangement: Incoming ring circuits, transformer feeders, terminal supplies and future extension requirements.
Switching units: Load-switch or switch-fuse arrangement; select the fuse combination for the transformer rating and network fault duty.
Protection & metering: Fuse or relay protection arrangement, CT ratios, metering and fault-indication requirements.
Cable interfaces: Cable count, cross-section, termination type and earthing connections.
Controls & enclosure: Operating mechanism, auxiliary supply and remote signalling; enclosure and site conditions for engineering review.

Project-specific options and accessories are confirmed in the quotation and approved drawings.