Ring Main Unit (RMU) is a compact, sealed for life metal-enclosed switchgear widely used in Urban Power Distribution Network. A Ring Main Unit includes a combination of one or more Load Break Switch (LBS) cum Earth Switch as incomer and outgoing feeder and  Vacuum Circuit Breaker with associated Disconnector and Earth Switch for load feeders.

Depending on the requirement, RMU is available in different voltage ratings and are suitable for both indoor and outdoor installation.

All the switching devices and the busbars are enclosed in a sealed for life SS enclosure filled with SF6 to make the design compact while ensuring a high level of safety and reliability and also a maintenance-free system. Some of the key features of the RMU includes SF6 gas insulation, compact and modular construction, integral protection system, fully extendable options, and low maintenance.

Applications of Ring Main Units

The Ring Main Units are used in underground cable distribution network at the load connection and junction points of a ring-type distribution network. Ring Main Unitare also suited for use in the following applications:

  • Compact secondary substations
  • Wind power plants
  • Solar power plants
  • Small industries
  • Hotels, office buildings, residential housing complex, shopping centers, business centers, hospitals, airports etc.

Advantages of Ring Main Units

The ring main unit is an innovative solution that makes it easier to manage the numerous challenges of electrical distribution. RMU is an all-in-one solution and is safe, easy to install and maintenance free switchgear helping the utilities improve reliability & uptime of the network and reduce the operational costs.

  1. Feature-Rich Compact Designs: Ring Main Unit is an SF6 insulated compact Switchgear equipped with SF6 Switch disconnector and vacuum circuit breaker. Its compact design requires least possible space to install and operate.
  2. Time and Cost Savings: RMU is a complete switchgear and is easy to install, saving installation and commissioning time. Independent of climate and resistant to environmental conditions, the operation and maintenance costs of these units are also low.
  3. Safety and Performance: Modern compact design and latest technology of the RMU ensure complete safety, connectivity, reliability, and efficiency.
  4. Smart Capabilities: When fitted with Intelligent Electronic Devices and Communication capabilities the RMU is easy to integrate with Distribution Management System and in building a Smart Grid solution.

In the modern urban power distribution system, Ring Main Unit is widely used across India and around the world to efficiently meet the growing needs of reliable energy. It’s one solution with comprehensive capabilities.