13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 1 Harmonic and Distributed Generation Interaction Issues in the U.S. Navy All-Electric Ship Program Center for Advanced Power Systems Florida State University Dr. Thomas Baldwin, P.E.

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 2 Motivation Drivers Newer Naval ships require significantly larger amount of energy and power (much greater than commercial ships) Pulse weaponry High-tech, high-power military loads The need for higher installed power places demands on: Energy conversion Power delivery system Prompting a move to a common energy / power platform Military requirements dictate the need for Low signatures (enemy identification) Non-interference (compatible with military operations) Damage tolerance (recovery and sustainability)

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 3 System Level Performance Electric Ships are more than electric-drive systems Includes power generation, distribution, and controls Other loads: Pulse-power and pulse-energy weaponry Electro-magnetic assistance launch (EMAL) Communication, computer, radar, and sonar Hospitality and service loads Power system design must be reliable and survivable Graceful degradation Operational after attack damage USS Cole - negative experience for the US Navy

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 4 System Philosophy Currents ac – conventional technology, common machines dc – electronic loads, energy storage, fuel cells hybrid – best of both worlds? Issues of controllability stability harmonics protection Challenges conversion between current forms losses

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 5 System Philosophy Distribution system topologies radial network traditional method for general electrical loads on ships loop-radial network improvement to reliability and handling pulse loads zonal network mesh (open or closed) network divided into controllable zones power electronic devices (PEBBs) couple the zones together controlled power flows, frequency/voltage conversions, filtering

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 6 Electric Ship System Concept Ship Service Power Main Power Distribution Propulsion Motor Drive Generator Prime Mover Power Conversion Module  Electric Drive  Reduce number of Prime Movers  Fuel savings  Reduced maintenance  Technology Insertion  Warfighting Capabilities VisionIntegratedPowerSystemIntegratedPowerSystem AllElectricShipAllElectricShip ElectricallyReconfigurableShipElectricallyReconfigurableShip  Automation  Reduced manning  Eliminate auxiliary systems  steam  hydraulics  compressed air Increasing Affordability and Military Capability Courtesy, ONR

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 7 Reconfigurable, Survivable Power Systems  Power Density  Energy Density  System Efficiency  Resource Management and Control Challenges: POWER GENERATION MODULE FUEL CELL POWER DISTRIBUTION MODULES ZONAL ELECTRICAL DISTRIBUTION SYSTEM Ship Service Inverter Module (SSIM) Ship Service Converter Module (SSCM) SYSTEM CONTROL Power Port Control Power Port LOAD SOURCE PEBB POWER ELECTRONIC BUILDING BLOCK COMBATREADINESS CASUALTY SHIP WIDE ELECTRICAL OUTAGE COMBAT ELECTRONICS SHUT-DOWN RECOVERY OF SUPPORT & THEN COMBAT TIMELINE MILLI-SECONDSSECONDSMINUTES + COMBATREADINESS CASUALTY ISOLATION OF DAMAGE/ RECONFIGURE ELECTRIC PLANT TIMELINE < 100 MILLI-SECONDS DETECT FAULT ~80 MICROSECONDS 2-8 SAMPLES COMBAT SYSTEMS STAY ON LINE ~ 1 MICROSECOND PER SWITCH TODAY FUTURE Courtesy, ONR

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 8 Integrated Power System Approach Flexible and Scaleable Power System Power Generation Module Power Distribution Module PGM-4 PDM-1 Propulsion Motor Module Propulsion Motor Module PGM-4 Propulsion Motor Module Propulsion Motor Module PGM-4 PDM-4 PDM-1

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 9 Technology: PEBBs Power Electronic Building Blocks may consist of ac/ac, ac/dc, and dc/dc converters performs multiple power system functions power flow control voltage transformation network protection serves as interface and controller between distribution zones to energy storage systems, fuel cell generation to pulse loads (e.g., EMAL, pulse weapons)

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 10 Technology: Propulsion Drives Propulsion Drives Move to propulsion pods pm synchronous machines ac induction motors dc homopolar motor Drive technologies ac / dc-bus / ac converter ac / dc converter dc / dc converter cyclo-converter

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 11 Harmonic Noise Well-known fact that converters and drives inject harmonic signals onto the electrical network supply-side noise can impact sensitive loads and network control and protection load-side noise can impact machine performance, insulation life, and mechanical bearings Cyclo-converters also introduce inter-harmonic signals as a function of the input and output frequencies

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 12 Typical Harmonic Levels Cyclo-converter at zero speed, showing classical harmonics

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 13 Typical Harmonic Levels Cyclo-converter at medium drive speed, illustrated interharmonics

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 14 Harmonic Sensitivity Sensitive ship loads radar systems, communication systems computer controls for weapons and navigation technical issues military computer systems have long restart times loss of critical loads are not acceptable to the Navy Currently used harmonic mitigation methods motor-generator sets isolated generation and distribution systems isolating UPS (dc link)

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 15 Harmonic Mitigation Typical Navy ship builder’s experience Design conversion of one class of submarines to an all- electric design electric drive reduced propulsion drive system size and weigh – eliminated the mechanical gearbox power system required extensive harmonic filtering consequence: overall vessel design length increased by 10 feet Novel Course of Action Harmonic zones some zones are permitted to operate with high levels of harmonic distortion zones are separated by PEBB units research of zonal approach is in the initial phase

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 16 CAPS Harmonic Research Program Challenge: increasing prevalence of solid state switching converters on a closely coupled AC or DC network that may create problems of harmonic distortion, resonance between system components and system stability Objective: characterize harmonic levels in an (isolated) integrated power system, which has yet to be built, and address any potential problems prior to construction Task: investigate the effects of harmonics in ship power components and loads, looking at parametric studies, hypothetical operating situation, and new technologies for power conversion, control and filtering Analyze zonal distribution system with mixed levels of harmonic distortion

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 17 CAPS Harmonic Research Program System and model verification initiative USCG Healy EMTDC studies on-board harmonic measurements during maneuvers real-time digital simulation of primary propulsion system Parametric studies on zonal distribution system Simulation studies of converters, drives, and PEBBs Time-domain computer simulations Hardware-in-the-loop tests on prototype power- electronic equipment

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 18 Simulation & Modeling Simulation of tightly-coupled power systems with power electronics and weak generation sources In the utility world, power system problems have been approached through simulation and modeling initially with scale analog models in the last 30 years with digital modeling Ship propulsion systems are modeled digitally using techniques developed primarily for mechanical and control system The heavy use of power electronics in ship systems creates a need to understand the system performance

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 19 USCG Healy Studies Ship power system modeling model development (Aug 2000-June 2001) propulsion load models of ship hydrodynamics propulsion drives, motor, and control system generation control and dynamics model verification (comparison with CG results) (Apr 2001-Nov 2001) performance design criteria ship design-phase simulations recorded data from ship data acquisition system

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 20 USCG Healy Program Ship’s one-line diagram

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 21 Real Time Modeling Utility industry uses real time digital simulation for hardware-in-loop testing of control systems and protective devices CAPS is acquiring a commercial real time simulation system sufficient to model a mid- sized ship system R-T simulator will be evaluated for performance with closely-coupled systems by studying the USCG Healy system Structure a research program focused on advancing the real time simulation capability

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 22 Power Test Bed CAPS is combining real-time simulation with power component testing in a hardware-in-the-loop facility to create a unique testing environment that will: provide capability to control source and load characteristics for hardware under test to emulate an actual power system condition provide dynamic response to equipment under test provide wide range of voltages & frequencies provide the capability to create system configurations that model new designs and applications provide easy reconfiguration capability for diverse equipment under test

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 23 G CAPS Test Facility 115 kV Transmission Lines (2) 30/40/50 MVA Transformers Feeders to Innovation Park Feeders to NHMFL CAPS System kV Main Experimental Bus 5 MVA Transformer 12.47kV / 750 / MW Converter 4-Q Operation DC Experimental Bus Adjustable: 500 to 2000 V 5 MVA Variable Voltage / Frequency Inverter 4160 V AC Experimental Bus (2) 2.5 MW Dynamometers Experimental Loads S 2 MW Bi-Directional Chopper BWX 100-MJ SMES Magnet Energy Storage HTS Substation Gas Turbine Generators (2) 2.5 MW To Perdom Generation Plant To Hopkins Generation Plant 3.5 MVA Transformer 12.47kV / 4160 Levi Steet Substation Utility System FCL 2.5 MVA Transformer 4160 / 450 V M MCC C D C D 5000 hp Motor Test Cell Test Machine and Controls G ~ = ~ = ~ =

13-15 March 2002 Power Systems Conference 2002 Impact of Distributed Generation 24 Summary and Conclusion Only an integrated power system makes economic sense for warships Large-scale use of power electronic devices in close- coupled systems cause harmonic problems at levels rarely encountered in utility or industrial environments All-electric ships need novel concepts for its integrated power system Building of knowledge base for modeling and simulation is needed Real-time simulation with power system components as hardware-in-the-loop will offer unique opportunity to study harmonic issues