The 11kV/12kV CCV indoor ring main unit is used to control the network and protect the distribution transformer. It assembled SF6 gas compact design. The ring main unit is a compact medium voltage, virtually maintenance free component, used for typical ring networks with the following features:
1. Ability to carry rated current continuously.
2. Ability to interrupt fault currents on the circuit breaker.
3. Ability to switch normal load currents on the circuit breaker.
4. Safe and reliable operation with interlocking between earth switch and disconnectors.
5. The RMU shall be so designed that it prevents the operator from making advertent contact with live parts when operating.
Design and Construction
1. The RMU is designed for future extension on one or both sides.
2. All external surfaces is coated with one coat of epoxy polyester type thermosetting powder paint.
3. The RMU is suitable for tropical conditions or frigid conditions. It is complete with suitable cable termination adapters for XLPE cables, operating handles and necessary facilities for cable testing.
4. Busbar conductors is radiused to minimise di-electric stress concentrations and is made of copper.
||Power Frequency withstand
|Lightning Impulse withstand Voltage (peak value)
||Rated short circuit breaking current (peak)
||Rated closed-loop breaking current
||Rated cable charging interrupting current
||Rated line cable charging interrupting current
||Rated off circuit transformer breaking current
||Rated making current (peak)
||Rated withstand current (peak)
||Rated short time withstand current
||Rated short time withstand time
||SF6 rated pressure (20℃)
||SF6 Annual leakage rate
||Secondary circuit rated power voltage
||Secondary citcuit 1min power frequency voltage
||RMU panel indoor installation
||RMU panel with outdoor enclosure