What Are the Common Ring Main Unit Types and Uses

Ring main units serve as a vital component in medium voltage power distribution systems and are designed in a variety of different structural and functional ways to meet different application needs. Different types of ring main units have been created to meet different surroundings—indoor or outdoor, high humidity or dusty— and to meet various functional needs, such as high dependability or lower servicing. As a professional power equipment supplier, GPSwitchgear tailors every type of ring main unit to ensure reliable performance in a variety of contexts, from remote industrial parks to urban commercial complexes. Each type solves a specific distribution problem, so let's review the most common types of ring main units and their typical applications.

SF6 Insulated Ring Main Unit Type: High Reliability for Harsh Environments

The SF6 insulated ring main unit type is known for replacing air insulation with the use of SF6 gas for insulation. SF6 gas is great at providing insulation, extinguishing arcs, and restricting moisture, dust, and other corrosive gases from coupling with high voltage apparatuses. The compact design (30-50% smaller than air insulated units) makes it easier to use in tighter locations. It is maintenance free for 5 to 8 years as the sealed gas chamber is stable, at which point gas may be replaced. It can be used in outdoor power distribution to the coast (salt spray corrosion resistance), industrial parks (high dust and chemical vapor), and urban underground power grids (wet environment). An example is using an SF6 insulated ring main unit type in a chemical industrial zone to power production lines while preventing the internal components from sustaining damage from corrosive gases. Gas pressure monitoring sensors for leak detection and gas pressure monitoring sensors for gas pressure monitoring offer dual tier monitoring which is essential in a chemical production facility. This also increases the reliability of the switchgear for small outdoor SF6 ring main units used urban underground power distribution and industrial parks.

Solid Insulated Ring Main Unit Type: Environmentally Friendly & Minimal Maintenance

Instead of using gas or air insulation, this type of Ring Main Unit encapsulates high-voltage components with epoxy resin and other solid insulating materials. As such, this type of Ring Main Unit is considered environmentally friendly because it does not emit greenhouse gases such as SF6, and it does not pose any risk to the environment due to gas leakages. Furthermore, the insulating solid materials do not age or become brittle, and their resistance to extreme temperatures allows the unit to function within a broad temperature range of -40° to 60° Celsius. For more than 20 years, the solid insulated ring main units require and maintenance and servicing because no gas pressure checking or insulating material replacement is needed. It is used indoors and in environments with sensitive power distribution such as residential areas, hospitals, and data centers. For example, solid insulated ring main units in data centers provide uninterrupted power to the servers.

The solid insulated ring main unit type from GPSwitchgear also utilizes high-strength epoxy resin. This improves impact resistance for more challenging environments, such as near subway lines, where frequent vibrations occur.

Cost-Effective Indoor Dry Environments with Air-Insulated Ring Main Units

Also referred to as the conventional air-insulated model, the air insulated ring main unit type has dry air as the insulating medium. Because of its uncomplicated structure, minimal development costs, and ease of maintenance, this type of ring unit gains popularity. Since internal parts can be directly reached, inspected, and repaired without special gas handling tools, it provides ease to the user. Nevertheless, it has greater space requirements compared to SF6 or solid insulated counterparts since air has a lower insulation efficiency. The air insulated ring main unit type is a perfect fit for dry and spacious indoor places such as power distribution rooms in commercial buildings, offices, and schools. Consider a shopping mall power room; the air insulated ring main unit type can be serviced off-peak, at night, to avoid any disruption to the business. The people at GPSwitchgear have designed this type to optimize air circulation, thereby limiting the chances of moisture condensation in the unit and making it usable in slightly humid places such as underground parking lot power distribution rooms. This is a significant improvement in terms of unit functionality.

Compact Outdoor Ring Main Unit Type: Space-Saving for Outdoor Distribution

This type of compact outdoor ring main units is engineered with outdoor installation in mind while ensuring reduced size and weather resistance. Designed with fully enclosed metal cases, these compact units can withstand rain, snow, dust, and direct sunlight. Compact variants usually occupy less than 2 cubic meters of space and can be installed in narrow areas, such as roadside green belts or corners of buildings. Furthermore, the compact outdoor ring main unit type also comes equipped with anti-condensation heaters and lightning protection to stand reliable use within more extreme conditions. Power distribution for street lights and shops located in urban residential areas and for rurally located open fields are several typical applications for the compact outdoor ring main units. Considerable miniature outdoor power stations are avoided and instead a few compact outdoor ring main units are placed along the mini residential community roads to each supply power to 2-3 residential buildings. Where outdoor environments are concerned, GPSwitchgear’s compact outdoor ring main unit type will use corrosion resistant aluminum alloy casings which will increase the service life to over 15 years.

Data-Driven Intelligent Ring Main Unit for Smart Grids

Data-Driven Intelligent Ring Main Unit for Smart Grids. The seamless integration of advanced monitoring, communication, and control functions positions it as a cornerstone of smart power grids. Equipped with an array of sensors, it captures real-time data on current, voltage, temperature, and load. Through communication modules (4G/5G, fiber optics), it links to the power grid’s SCADA system or the cloud for remote monitoring, control, and fault diagnosis. Smart Intelligent Ring Main Units automatically detect and isolate system faults (short circuits or overloads) in mere seconds, minimizing outage duration. Applications span smart cities (real-time urban power grid monitoring), smart industrial park energy optimization (power adjustment for real-time needs), and large commercial complexes with managed peak load. For example, in a smart industrial park, it optimizes energy and cuts costs by adjusting the power supply to factories according to real-time production needs. This type of intelligent ring main unit incorporates AI for fault prediction by analyzing data and forecasting risks for proactive maintenance, further enhancing grid efficiency.