1 40 MW 20 MW 15 MW 11 MW5 MW HFAC Baseline Architecture: modeling status R. Hebner A. Ouroua Center for Electromechanics The University of Texas at Austin ESRDC/Purple team meeting 20 August, 2010 Arlington, VA

2 Starboard Power Distribution Bus Stern Cross-hull Disconnect Zonal Ship’s Service Loads Port Power Distribution Bus Special Load Auxilary PGM 2 Main PGM 2 Main PGM 1 Auxilary PGM 1 Starboard PM VSD Port PM High Power Pulsed Load Energy Storage Bow - Stern Disconnect HFAC Architecture Top-level Electrical One-line Diagram (Common to all 3 Architectures)

3 Zone 1 Loads Radar Load Auxilary PGM 2 Main PGM 2 Main PGM 1 Starboard PM VSD Port PM High Power Pulsed Load Energy Storage HFAC Architecture Main Features 240 Hz, 4.16 kV Zone 2 Loads Zone 3 Loads Zone 4 Loads High-frequency transformers (size reduction) HF-PCM1 GT ATG MTG Auxiliary PGM 1 High pole-count (less back iron) (size reduction) High speed generator & no gear box (size reduction) High-frequency bus

4 Generation power80 MW Distribution frequency240 Hz Distribution voltage4.16 kV Prime moversGas turbines 2x 36MW/3600rpm twin-shaft 2x 4MW/~14400rpm single-shaft GeneratorsSynchronous wound-field cylindrical rotor 2x 45MVA /3600rpm /8-pole /0.8Pf 2x 5MVA /14400rpm /2-pole /0.8Pf Propulsion (x2) 6-pulse passive rectifier Filter and voltage regulator Current-controlled hysteresis PWM inverter Permanent-magnet synchronous propulsion motor (36.5MW/120rpm) Service loads4 Zones (22 total loads) Special loadRadar load Pulse loadFree Electron Laser (FEL) Energy storage 100 MJ Flywheel module 100 MJ Li-ion battery module Switch gears 3-phase AC breakers Semiconductor switches (DC breakers) HFAC baseline power system definition Note: Prime movers/Generators configuration not optimum for HFAC architecture. Current configuration selected for commonality with 60Hz MVAC and MVDC architectures.

5 Modeling environment Software Packages Matlab/Simulink (yes)Latest version PSCAD (yes)Version newest version = PSCAD X4; Should/can everybody use this version? Saber (no)Too expensive (Single license 1 year lease = $36,750)

6 Modeling approach Develop two models: Model for dynamic analyses (step loads, faults, power transfer,…) Model for top-level analyses (load flow, fuel consumption, size, cost,..) Dynamic model: Keep model simple to reduce data size and execution time use simple topologies and components Use largest simulation time step that: captures dynamic features allows reasonable execution times on desktop PCs 10 μs seems to be a good compromise Model should be representative of a testable system, sub-system, or component Use parameters of existing components whenever possible Top-level system model Extract top-level model from dynamic model Model should have same structure as dynamic model

7 HFAC architecture baseline model Zone 1 Loads Radar Load Free Electron Laser Energy Storage 240 Hz, 4.16 kV Zone 2 Loads Zone 3 Loads Zone 4 Loads HF-PCM1 GT ATG MTG GT ATG GT MTG ~ = ~ = = ~ = ~ PM One-line diagram of modeled system

8 Matlab/Simulink HFAC baseline model

9 Turbo-generator models Gas turbine models Used generic time constant-based models These models are suitable for dynamic analysis and used for testing power installations Model data estimated using published test results from several power plant installations Learning about methods and tests needed to calibrate turbine models when an installation becomes available for testing. Generator models Synchronous machine model with 1 d-axis damper winding 2 q-axis damper windings

10 Propulsion model Controller

11 Service load models HF-PCM1 Zone 1 loads

12 Service load model (cont’d)

13 Pulse load model (Free Electron Laser System) About 25 MW needed for ~3 MW FEL beam Requires several power conversion modules

14 Initial model testing/debugging results Run simple testing/debugging exercise to estimate run-time and check numerical instabilities… Model ran as shown on slide 8 (no energy storage) All 22 service loads (assumed RL) turned on and off and both propulsion power trains on Radar loads and pulse loads turned on and off Load breakers and switches opened/closed through pre-programmed timers Main ring bus segmented (MG1,2 supply power to propulsion, radar, and pulse load; AG1,2 supply power to zones 1 to 4) Initialization run Gas turbines and generators ramped-up to speed Ran overnight Saved final conditions 10 seconds test run Run 10 s scenario turning power on and off to all loads at different times Used final conditions (saved earlier) as initial condition 10 μs time step several scopes were on (adds to computation overhead) Used average performance PC (~4-year old) x64 bit / Intel Q6850 / 3.0 GHz / 8 GB RAM Initial test results 10 s scenario completed in ~ 2h 33min Power levels delivered to various loads ~ as expected Propulsion DC voltages dropped more than expected at high power… Other observations suggesting adjusting control parameters, machine parameters, etc…

15 Some traces to check model Service loads DC buses not filtered Voltage and current levels in some DC loads can’t be checked directly (too noisy) Several other observations… Service loads: transformer voltages and currents as load power turned on/off (in 4 zones) Gas turbine: torque, speed, and power as loads are turned on/off Main DC bus voltage check: ~ 6000 Vpeak (for vLL = 4.16 kV) ~ 4 ms period (for 240 Hz) Zone 1Zone 2Zone 3Zone 4

16 Some traces to check model (cont’d) Speed Phase voltages d-axis voltage EM torque Output power Rectifier DC voltage Rectifier DC current Filter DC voltage DC current into inverter Motor speed Motor phase voltage Motor phase current Motor EM torque Motor output power Main generator 1Propulsion DC link 1Propulsion motor 1

17 On-going and remaining work Add energy storage module to HFAC model Considering adding a Li-Ion battery module (flywheel module also available) Consider approaches to load sharing among prime movers coordinate with other team members Run additional tests… Verify model outputs are as expected (steady state values…) Check machine parameters and collect additional turbine and generator data Simplify model further… Reduce 10 s run time … reduce stored data…run model on faster machines Determine or estimate model validity range Continue model development in PSCAD environment Coordinate work further with MVDC and MVAC teams Set-up scenarios Develop experimental tests to validate model Seek test facilities and/or resources Run tests, improve and validate model Other…