Why Ring Main Unit (RMU) Matters in Power Distribution

Introduction

A smart ring main unit might be the ideal medium-voltage switchgear for residential complexes or industrial situations that require greater control.

A typical ring main unit, or RMU, is a medium-voltage switchgear used in electrical power distribution networks. They provide continuous power while also allowing you to switch power sources in the event of a repair or an emergency. The newly developed smart RMU provides safe grid connectivity and integrates smart sensors for continuous system monitoring.

The Basics of Ring Main Unit (RMU)

A Ring Main Unit (RMU) is a medium-voltage cabinet with input and output cable compartments. It isolates these discrete compartments using single breakers attached to cables leading to transformers. Each compartment has a load breaker and a protection fuse attached. Smart RMU cabinets come standard in two, four, and six-compartment configurations.

Each cabinet will have several sorts of switches that can serve a variety of functions. For example, one switch may power a distribution transformer while another connects to a load. These highly compact power distribution devices are used for medium-voltage power applications. Smart RMUs can be built for a variety of topologies, with the 24kV distribution network being the most popular nowadays. It’s critical to understand that each cabinet or unit is a fully sealed system.

Types of Ring Main Unit

There are three types of ring main units that you should be familiar with. These are gas-insulated, air-insulated, and solid-insulated. Each is important for a specific type of application. This is why you must understand the distinctions between them, so you can select the best smart RMU for your specific needs.

Gas-Insulated RMU

Gas-insulated RMUs are ideal for both indoor and outdoor secondary distribution networks. ABB’s SafeRing and SafePlus RMUs, for instance, ensure reliable performance up to 40.5kV, providing continuous protection for your electrical equipment. They are appropriate for use in power plants, industrial zones, transformer substations, and other applications. These types of RMUs are the most commonly used on the market today.

Air-Insulated RMU

Air-insulated RMUs are airtight cabinets with a vacuum load switch as the primary switch. These metal enclosures are extremely durable and designed to withstand harsh environments. They are ideal for industries, enterprises, high-rise structures, and residential complexes.

Solid-Insulated RMU

Solid-insulated RMUs are commonly made with oil as the insulating medium. They are specifically engineered to endure corrosive and harsh situations. It is suited for use in oilfields and mining operations.

Importance of Ring Main Unit (RMU)

Smart RMUs are perfect for assisting you in addressing the numerous difficulties of power distribution. These all-in-one solutions provide safe switchgear that is simple to install for a variety of voltages.

They are designed to resist extreme environmental conditions and may be used both indoors and out. These intelligent RMU systems provide improved protection against overload currents, phase-to-phase fault currents, and ground contact currents.

Applications of Ring Main Unit (RMU)

RMUs are used in a variety of underground cable transmission network applications where medium voltage power distribution is required. They are in high demand among companies that require a continuous and consistent power source and can afford the unit’s higher upfront cost.These include residential complexes, commercial centres, hospitals, resorts, airports, metros, solar power plants, wind power plants, tiny secondary substations, and many more. They’re perfect for reducing downtime because any interruption in the power supply may be quickly replaced using manual or automatic switching.

Conclusion

RMUs are an essential part of any contemporary power distribution system. They protect the system from overloads and short circuits while also providing steady power and isolating malfunctioning equipment when problems arise.

ARC Technologies offers the ABB medium-voltage ring main unit. Contact us to learn more about our offerings.

FAQs

An RMU is a medium-voltage switchgear that ensures continuous power, enables safe switching during maintenance or faults, and protects against overloads. Smart RMUs add sensors for real-time monitoring and control.

ABB’s SafeRing and SafePlus RMUs are used in residential complexes, industries, substations, power plants, airports, hospitals, and renewable energy projects, both indoors and outdoors.