RMU (Gas Insulated / Secondary)
In an electricity distribution grid, a ring main unit (RMU) is a factory assembled, metal enclosed set of switchgear used at the load connection points of a ring-type distribution network. It includes in one transformer protection units, two line switches that can connect the load to either or both main conductors, and a fusible switch or circuit breaker and switch that feed a distribution transformer.
Ring main units can be characterized by their type of insulation: air, oil or gas. The switch used to isolate the transformer can be a fusible switch, or may be a circuit breaker using vacuum or gas-insulated interrupters. The unit may also include protective relays to operate the circuit breaker on a fault.
|Rated Voltage||kV||12 … 40,5 kV|
|Rated Power Frequency Withstand Voltage||kV||10 … 85 kV|
|Rated Lightning Impulse Withstand Voltage||kV||40 … 185 kV|
|Short-Circuit Breaking Current||kA||16 … 25|
|Short-Time Withstand Current, 1/3s||kA||16 … 25|
|Rated Current||A||200 … 630|