Ring Main Unit (RMU)
A compact factory-assembled HV switchgear set for ring-type or radial distribution networks.
An RMU is a compact MV switchgear set at distribution points where distribution transformers connect to the MV network.
Combines: load-break switches, fuse-switch combinations or circuit breakers for transformer protection, busbar connections for ring topology. Enables flexible reconfiguration and supply continuity.
Configurations: 3-way, 4-way, 6-way. Modern types use SF6 or vacuum technology. See grounding guide for RMU grounding.
QDTB manufactures RMUs up to 24 kV / 630A, used in urban distribution and public facility projects.
Related Products
Related Terms
Switchgear
Equipment for switching, controlling, and protecting electrical circuits including breakers and relays.
Distribution Transformer
A transformer stepping down voltage from the distribution network (11-33 kV) to utilization voltage (400/230V) for end consumers.
Prefabricated Substation
A factory-assembled complete substation integrating transformer, switchgear, and protection for rapid installation.
More Terms Starting with “R”
Reactor
An inductive device in power systems to limit current, absorb reactive power, or filter harmonics.
Rectifier Transformer
A transformer designed to supply rectifier/inverter loads with enhanced harmonic and DC magnetization handling.
Voltage Regulation
The change in secondary voltage from no-load to full-load as a percentage, indicating voltage stability.
Rated Capacity
The maximum continuous power output a transformer can deliver at specified conditions without exceeding temperature limits.
More in “Components & Accessories”
Bushing
An insulated device allowing a conductor to pass through a grounded barrier while maintaining insulation integrity.
Busbar
A metallic strip conducting electricity within switchgear, transformers, and distribution equipment.
HV/LV Bushing
High-voltage and low-voltage insulated conduits for transformer winding connections through the grounded tank.
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