SC6 Ring Main Unit (RMU)

The 11 KV switchgear incorporated forms a ring main unit consisting of two (or three) switches for incoming cable feeders and one fuse switch for the transformer. The switchgear is of the completely enclosed type, with (SF6) gas sealed insulated chamber or with vacuum interrupters with insulated bus-bar of (800 or 1000 or 1250) AMP rating. The switchgear is provided with inter locks and adequate safety devices to prevent access to the live compartment . Earthing device is of built in type and is provided for earthing the cables. The switch is of a single break type having ON/OFF and earth position with quick make and break features in all positions. The switch is capable of making, carrying and breaking currents under normal circuit conditions which may include specified operating overload conditions and also carrying for a specified time currents under specified abnormal circuit conditions such as those of short circuit . It is capable of making, but not breaking short circuit currents and it has continuous current rating of 630 AMP. The operating mechanism is of local hand control spring assisted type with lockable ON/OFF and Earth positions and indication for switch position. The switch has mechanical interlocking for earthing switch is such that it cannot be closed unless the switch is in the off position and the front doors cannot be open unless the earthing switch IN /ON position. Potential indicators is provided with neon lamps and placed on the cable side in order to indicate whether the cables energized or not .The fuse switches is hand operated totally enclosed in line with the switch panel. The fuse switch is of triple pole with provisions for automatic tripping in case of failure of any fuse. Furthermore re-closing cannot carry out unless the burnt fuse is replaced. The switch fuse is capable of switching ON/OFF the normal load current and has a continuous current rating of 400 Amperes with a cartridge fuse according to the size of the transformer .The switch fuse includes the following :§ Set of insulated bus bar in air insulated bus bar chamber§ One fuse switch 400 Amp rating.§ Three cartridge (HRC) with striker fuse of rating according to transformer rating.Short circuit and earth fault indications is provided on each kiosk with indicating lamps on the front door of the kiosk with cancellation facility.The modular SC6 range is a range of harmonised cubicles equipped with SC6 or vacuum air breaking technology switchgear.These cubicles allow you to produce all your Medium Voltage substation requirements up to 24 kV by superposing their various functions.The result of in-depth analysis of your requirements, both now and in the future, SC6 cubicles mean that you can take advantage of all the features of both a modern and proven technology.The ranges advantagesUpgradeabilitySC6, a comprehensive range¤ a comprehensive offer covering your current and future requirements;¤ a design adapted to the extension of your installations;¤ a product designed to be in compliance with standards constraints;¤ options to anticipate the telecontrol of your installations.CompactnessSC6, an optimised range¤ compact units, with low increment cubicles;¤ rationalised space requirement for switchboard installation;¤ reduction of civil works costs;¤ easy integration in factory-built outdoor substations for which the SC6 is particularly well designed.MaintenanceSC6, a range with reduced maintenance¤ the active parts (breaking and earthing) are integrated in an SF6-filled, sealed for life unit;¤ the control mechanisms, are intented to function with reduced maintenance under normal operating conditions;¤ enhanced electrical endurance when breaking.Ease of installationSC6, a simple range to incorporate¤ reduced dimensions and weights;¤a solution adapted to cable connection;¤simplified switchboard busbar design.Ease and safe to operateSC6, a proven range¤ a three position switch to block incorrect switching;¤ the earthing disconnector has full closing capacity;¤ positive breaking of position indicators;¤ internal arcing withstand in the cable and switchgear compartments;¤ clear and animated display diagrams;¤ switching lever with an anti-reflex function;¤ compartmented cubicles.SC6 Range SwitchUnitSpec.Rated voltagekV12Rated frequency (power frequency)Hz50Rated continuous currentA630Insulation levelRated insulation level at power frequencykV42/4850Hz,1minPeak withstand voltage (1,2 / 50 μs)kV95/110(contact to earthing/Contact to contact)peakShort time withstand currentThermal withstand currentKA/s20/3,25/1Peak withstand currentKA/peak50/60Magnetising current of no load transformerA16Cables off loadA25Maximum breaking shift currentA1750Rated closed loop breaking currentA630Maximum fuse rated currentA125Distance between polesmm200Mechanical endurance timesMain circuittimes2000Earthing circuittimes1000Ambient air temperatureservice-5 +40reserve-40 +70