Ring Main Unit

RM6 is an indoor gas-insulated switchgear

up to 24kV for secondary distribution

networks. It meets all distribution needs in more complex

network configurations

Features

• Standard: IEC 62271-200
• Rated voltage: Up to 24 kV
• Frequency: 50 or 60Hz
• Rated current busbar: 630A
• Rated current for Load Break switch: 630A
• Rated current for Circuit breaker 200A (for transformer protection) ,630A (for Feeder Protection)
• Busbar system: Single
• Short circuit rated current: Up to 21kA 1 sec
• Internal Arc Classification: Up to 20kA AFLR with options
• Loss of service continuity: LSC 2A
• Partition class: PM

RM6 meets the definition of a “sealed pressure system” as laid out by the IEC standard.

RM6 is made up of the following elements:

1. A stainless steel tank filled with SF6 gas (at 0.23 bar relative pressure), sealed for life and containing the busbar and all live switching components such as the switch disconnector, the earthing switch, the fuse switch combination or the circuit breaker
2. One to four (five optional) cable compartments with interfaces to connect to the network or the transformer
3. User interface with single line diagram, actuators and LV components
4. Manual or motorized operating mechanism compartments
5. Earthing circuit with visible earthing contacts

Range description

Operating conditions and standards

IEC 62271-200

(AC metal enclosed switchgear and controlgear for rated voltage above 1 kV and up to and including 52 kV)

• Switchgear classification: PM class (metallic partitioning)
• Loss of service continuity: LSC2 class
• Internal arc classification up to A-FLR 20kA 1 sec. (Please refer to section referring to internal arc performance for precise values)

Switch disconnectors

• Class M7/E3
• 100 CO cycles at rated current and 0.7 p.f.
• 1000 mechanical opening operations.

Circuit breakers:
200 A feeder or 630 A line protection

IEC 62271-100 (high voltage alternating current circuit breakers)

• Class M1/E2
• 2000 mechanical opening operations,
• 0-3 min.-00-3 min.-CO cycle at rated short circuit current

Other applicable standards

IEC 62271-100 (high voltage alternating current circuit breakers)

• Switch-fuse combinations: IEC 62271-105: alternating current switch-fuse combination.
• Earthing switch: IEC 62271-102: alternating current disconnectors and earthing switches.
• Electrical relays: IEC 60255.

RM6 Protection Index

• Tank with NV parts: IP67
• Front face + mechanism: IP3X
• Protection against mechanical impact: IK07