Why Diesel Electric Propulsion ? System alternatives. Technical features Why Diesel Electric Propulsion? TYPICAL ARGUMENTS: Fuel Savings Offshore: 25 - 40% reduction! Reduced maintenance cost More on board maintenance Safety Redundant Propulsion with FP Azimuths Design Improved design due to DEP IGBT = Insulated Gate Bipolar Transistors What makes diesel-electric propulsion attractive? Indications that diesel electric propulsion is more favourable : • Operation modes with low load during longer periods • Large on board electrical load • Dynamic positioning • High demands for low noise and vibrations • High demands for manoeuvrability • High demands for redundancy and availability • Etc. Choice of propulsion system for a vessel “The hull and propeller type is chosen on basis of the needed hydro-dynamic efficiency” “The propulsion system is chosen on the basis of the the operational profile (or special demands) to the vessel” Lips: Shaft and rudder (CP) Schottel: Hub Azimuth (FP) FP = Fixed Pitch CP = Controll. Pitch Choice of propulsor Conventional Controllable Pitch Propeller (CPP) Typical for Diesel mechanical propulsion system High ratings Low cost (?) Also with Diesel electric Propulsion Schottel: Tunnel thr.(FP) Aquamaster: Azimuth (FP) Contra rotating Schottel: Azimuth (FP) Twin Propeller FP = Fixed Pitch CP = Controll. Pitch Hybrid Diesel electric Propulsion Choice of propulsor Azimuth Thruster(s) Typical for Diesel Electric Propulsion system Controllable or fixed pitch With or without nozzle Contra rotating, Duo propeller POD Schottel: Tunnel thr.(FP) Aquamaster: Azimuth (FP) Contra rotating Schottel: Azimuth (FP) Twin Propeller FP = Fixed Pitch CP = Controll. Pitch Reduced Fuel Consumption Specific Fuel Consumption: High load on running diesels Improved SFC 360,0 350,0 Spesifikt forbruk (g/kWh) 340,0 330,0 320,0 31 0,0 300,0 290,0 280,0 270,0 260,0 250,0 240,0 230,0 220,0 21 0,0 200,0 1 90,0 1 80,0 1 70,0 1 60,0 0 500 1 000 1 500 2000 2500 3000 3500 4000 4500 5000 effekt (kW) 12M32C/600rpm 1xCAT 3508BTA 2xCAT 3508BTA 5500 6000 Reduced Fuel Consumption Propeller Efficiency: Optimum Propeller Efficiency with speed control Reduced Fuel Consumption Savings: Drastically improved propeller efficiency at low load! Equal or better propeller efficiency at high load! CPP contra FP? Improved Specific fuel consumption (?) Losses: Typically 10 - 12 % from shaft to shaft. Total: Typical ROV vessel: 25 - 40% reduction compared to conventional systems!! Coast guard vessels ?? Diesel mechanical propulsion Twin screw, CP conventional propellers Diesel engine Generator set Gear with clutch Generator Y/D Starter Propeller (CP) Tunnel thruster (CP) Y/D Starter Diesel electric propulsion Twin screw – FP azimuth thruster GPA Generator Power Adaptation Power Management (PMA 300) Integrated Automasjon Thrustercontrol Short circuit analysis •Harmonic analysis Diesel electric propulsion Typical single line diagram Diesel engine Generator Main Switchboard Transformer (12 pulse) Frequency converter Propulsion motor Propeller (FP) Tunnel thruster (FP) Hybrid Propulsion An golden compromise? HYBRID PROPULSION Single screw - System layout Hybrid Propulsion Twin Screw, CP propellers HYBRID PROPULSION Twin Screw - System layout Winch Bow Thruster 2200 kW Stern Thruster 883 kW Winch Shaft Generator Motor 5300 kW Azimuth Thruster 2200 kW Motor 5300 kW Shaft Generator Stern Thruster 883 kW Vessels suited for diesel electric propulsion Offshore vessels Research vessels Navy/ Coast guard vessels MASTERDRIVES Water Cooled Frequency Converter 6 Pulse and 12 Pulse operation Voltage: 690 V Power: 1200 kW 800 kW 630 kW Width: 1840 mm 1540 mm 1540 mm 440 V 710 kW 630 kW 1840 mm 1540 mm Additional 300 mm for internal cooling unit Standard Height 2100 mm Depth 640 mm The unit is the most compact on the market! MASTERDRIVES Parts of a Frequency Converter Transformer Rectifier Capacitors Inverter Output Generator Power Adaptation System Generators GPA GPA GPA GPA Main Switchboard Conv. Transformer Freq. Converter Propulsion Motor GPA GPA Generator Power Adaptation System P G 170 ms t [ms] Next generator GPA f U M GPA - The ultra fast dynamic load limtation system. The system adapts and limits the propulsion power according to the actual available generator capacity. The GPA is not a part of the PMS (Power Management System) Pre-charge Circuit The pre-charge circuit limits the in-rush current on start-up to a minimum by pre-charging both the converter transformer and the capacitors. D y d Pre-Charge Contactor Pre-Charge Reaktor Converter Transformer Frequency Converter Line Side Rectifier Inverter on the Motor Side Propeller Drive Motor Non heavy consumer Frequency Converter Propulsion System... Power Consumption Only - takes active power (kW) only from the main supply (and some excitation current for the converter transformer if present) Pre-Charge Circuit - converter transformer and DC-voltage capacitor bank - via the auxiliary supply. - main circuit breaker can be closed without any in-rush current. - in-rush free current start-up GPA System (Generator Power Adaptation) - fast acting monitoring and control system - no more power consumption than available from the highest loaded generator - no generator is overloaded - possible to run the propulsion on one small generator ...as a Non Heavy Consumer Type of Frequency Converter Harmonic feedback 6-pulse rectifier 12-pulse rectifier Active Front End 6-pulse rectifier Current harmonic feedback Single 6-pulse Diode Rectifier Brigde Transistor Inverter Brigde (IGBT - Insulated Gate Bipolar Transistors) 12-pulse Rectifier Current harmonic feedback Double 6-pulse Diode Rectifier Brigde Transistor Inverter Brigde (IGBT - Insulated Gate Bipolar Transistors) Active Front End Current harmonic feedback Transistor Rectifier Brigde Transistor Inverter Brigde (IGBT - Insulated Gate Bipolar Transistors) ”Back to Back” Quasi 24-pulse rectifier Current harmonic feedback 24-pulse 12-pulse -7,5° 12-pulse +7,5° +30° +30° Optimal when: Pload= 50% Pload= 50% Additional phase shift between transformers give 24-pulse feedback Harmonic Voltage Level Typical Calculated Values Harmonic Voltage Level 14 % 6-pulse 12 % 12-pulse AFE 10 % 8% 6% 4% 2% 0% 5 7 11 13 17 Harmonic Order 19 23 25 System solution Harmonic feedback Typical THD: •6-pulse: 16+% •12-pulse: 7-8% •q24-pulse: 3-5% •q36-pulse: low For Further Improvement: •230 / 450V Filters