Ring Main Units

Ring Main Units (RMU) is used for the secondary distribution network. RMUs can be supplied in several configurations suitable for most switching applications in 12/24/36/40.5 kV distribution networks. They are extendible and combined with the modular compact switchgear, they represent a complete solution for 12/24/36/40.5 kV secondary distribution networks. RMUs have identical user interfaces.

It is a completely sealed system with a stainless steel tank containing all living parts and switching functions. A sealed steel tank with constant atmospheric conditions ensures a high level of reliability as well as personnel safety and a virtually maintenance-free system.

RMU offers a choice of either a switch fuse combination or circuit breaker with relay for protection of the transformer. They can be supplied complete with an integral remote control and monitoring unit.

RMUs are designed for use in the following applications:

  • Compact secondary substations
  • Small industries
  • Wind power plants
  • Hotels, shopping centres, office buildings, business centres etc.
  • Light mining applications, airports, hospitals, tunnels and underground railways

Available modules:

Cable switch
Switch-fuse disconnector
Vacuum circuit-breaker
Busbar sectionalizer
Busbar sectionalizer
Direct cable connection
Direct cable connection with earthing switch
Busbar earthing
Circuit-breaker module
Metering module
Metering tariff module

Rated voltage (kV) ..40.5
Rated current 630
Rated short time current 3s (kA) 21