Download Document 7811210

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