3RMUs Presently Used What is an RMU? Who operates it? Are there safety concerns?
4RMU OperationOpening/closing of the load break switch or earthing switch:Key/leverPushed to overcome spring forceTurn 90˚ at ~20 N.m (clockwise or counter-clockwise depending on usage)Who operates it?Are there safety concerns?Can it function remotely?
5Project ObjectivesTo design a motorized retrofit for automatic operation of (F&G*) Ring Main Unit (RMU) as per technical specifications provided by TNB Distribution.
7DeliverablesA prototype RMU Motorization Unit for operation of manually operated F&G* Ring Main Units.
8Project ImpactThe proposed system would be able to switch the RMU breakers in a safe manner via remote control.Reduce downtime via remote operation and enhance the safety of TNB’s personnel by eliminating the need for manual operation of the RMU.
9Project Methodology Stages of prototype development: Torque and dimension measurementsStudy of Actuation MechanismGrip frame design and material selectionSensors & AlignmentPower & ControlsTesting & Trials
10RMU Automation Operational Block Diagram Auto/RemoteManual pushrelays &IndicatorsLocal/ManualCWLocal/ManualCCWM1Power Supply UnitMotor Driver w max current limitM228VDC 10ACW/CCWcontrol signalM3MicrocontrollerLoad switch limit switchSCADA
11Components List Power supply unit Grip Frame Motor Mounting Rails AssemblyProgrammable Logic ControllerMotor Driver/controllerAuto/Manual Cam Selector SwitchPush Power RelaysLimit/position SensorsGeared DC MotorsMiscellaneous
12FeaturesLight-weight (require only one person for mounting & installation)Simple gripping and holding mechanismReady for remote and local operationCompletely detachable motor unit for manual operationContinuous Breaker load switch status indicatorMotor over-current protectionResponse time of < 5 secondsMotor interlock operation
13Estimated Costing* per 2+1 RMU (3 motor set) Mechanical works (motor mounting and grip frame) – ~ RM1300Geared motors – 3 x RM700Controller – RM400Motor driver – RM700Sensors and electronics components – RM400Power Supply Unit – RM900 (for prototype only)TOTAL COST – ~RM5000 (without PSU)* For large quantities of order
14Initial survey and testing in ILSAS Load breaker switch sizingInitial motor selection
15Continuation of motor selection Motor mount and torque testing