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Alternative DC Storage Examples. Beyond the Lead Acid Battery. Power Quality Applications. Typical UPS system block diagram. Long-term AC alternate source. Genset AC. Double Conversion UPS System. Inverter DC/AC. Automatic Transfer Switch. Critical AC output. Rectifier AC/DC. ATS.
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Alternative DC Storage Examples Beyond the Lead Acid Battery
Power Quality Applications Typical UPS system block diagram Long-term AC alternate source Genset AC Double Conversion UPS System Inverter DC/AC Automatic Transfer Switch Critical AC output Rectifier AC/DC ATS 540 VDC Utility AC 480 VAC DC Energy Storage
Alternatives to Standard Storage • Generator • Preferred method to provide long ride-through (5-48 hours) • Maintenance is required • Noise and exhaust are concerns • Be sure to size properly with UPS • Vendor should have UPS interface experience
Alternatives to Standard Storage • Batteries • For now, batteries are the least expensive mid- term solution • They can also be the weakest link • Service life is always an issue • Hazardous materials disposal is a challenge • Frequent testing and constant monitoring is a requirement • Size and weight are inconvenient in a datacenter
Flywheel DC Energy Storage Can be deployed as the primary DC source or in parallel with traditional batteries in a Battery Hardening configuration. It is different from typical chemical batteries in that frequent cycles do not reduce its life Produces high power output for short durations (20 – 90 seconds)
TV Broadcast • 1 x 160KVA/144kW UPS • 1 VDC XE flywheel • No Batteries • Selection Criteria Green initiative Improved reliability Do not like batteries Floor space / footprint
Green initiative Improved reliability Do not like batteries Floor space / footprint Decatur Memorial Hospital IL - IT Application • 1 x 160KVA/144kW UPS • 1 VDC XE flywheel • No Batteries • Selection Criteria
University of Florida Proton Therapy Institute - Gainesville • 2 x 750KVA/675kW UPS • 8 VDC XE flywheels • No Batteries • Selection Criteria • Small footprint • Reduced Maintenance Cost
Gundersen Lutheran Hospital - IT Application • 1 x 550KVA/495kW UPS • 2 +1 future VDC XE flywheels • No Batteries • Selection Criteria • Small footprint • Green / Sustainability • Reliability • Reduced Maintenance Cost Strives for 100% Renewable Energy The hospital, based in La Crosse, Wis., is halfway toward its 2009 goal, which amounts to $409,000 in annualized savings
University of Massachusetts Medical School - Data Center • 2 x 825KVA / 750kW UPS • 8 VDC XE VYCON Flywheels • No Batteries • Selection Criteria • Small footprint • Green / Sustainability • Reduced Maintenance Cost • Reliability
Delta Dental Insurance - Data Center • Selection Criteria • Floor space / footprint • Redundancy • Extend battery life • Improved system reliability • Ride through to Generator Battery Hardening • 2 x 500kVA / 450kW UPS • 4 VDC XE VYCON Flywheels • Batteries • Dual Bus
Bremerton Naval - Modular Solution for IT • 825kVA / 750kW UPS • 5 VDC XE Flywheels • Outdoor Enclosure • Selection Criteria • Floor space / footprint • HVAC requirement reduced • Reduced maintenance • Improved system reliability • Ride through to Generator
The Principles of Kinetic Energy KE ~ m (rpm)² (for rotational motion) Low Speed More mass means more energy Double mass = double energy “Low-speed” 1800 to 8000RPM High Speed More energy by higher rpm Double rpm = quadruple energy “High-speed” 36000 to 55000RPM All Flywheels are operated well below their design limitations
First Generation Design - Low speed (8,000 RPM) High maintenance with down time required Lengthy commissioning and start up procedure Large flywheel mass (800 LBS) High standby power losses Bearings Flywheel Technology Evolution
250kW Motor/Generator/Flywheel Field replaceable ball-bearing cartridge Field coil Magnetic bearing integrated into field circuit Flywheel, motor-generator rotor Air-gap armature No permanent magnets enables high tip-speed and high output power Smooth back-iron, no slots and low loss Active Power FLYWHEEL
Second Generation Design Ultra high speed - 52,000RPM Liquid cooled - circulation pump Mid range power density Small composite flywheel mass (60 Lbs) No recovery from drop out event Down time to service internal vacuum / filter Bi Annual service with shut down year 1 Flywheel Technology Evolution
Third Generation Design – VYCON High speed - 36000 RPM Air cooled Small steel alloy flywheel mass (120lbs) Annual service requirement 15 mins. no down time High power density Full recovery from drop out event Flywheel Technology Evolution
High Speed, Steel Flywheel ModulePermanent Magnet Motor-Generator Magnetic Levitation
VDC – Simplified One Line Flywheel Module IGBT Power Converter Soft Start To UPSBattery Input DC Monitoring Motor Generator Controls Magnetic Levitation Controller Power Conversion Module Controller Control Panel
Battery HardeningBattery “Whiplash” Prevented Flywheel provides voltage support eliminating battery whiplash Increasing battery life, Improving UPS reliability & Reducing service 98% of disturbances< 10 sec. Gen 10 Nearly 99% of all voltage sags and outages last less than 8 seconds Float Voltage Grid Disturbance w/ flywheel UPS DC Bus Voltage (dc) Coup de fouet = Whiplash 20 0 Time(Seconds)
Alternatives to Standard Storage • Supercapacitors, Turbines and Fuel Cells • All these promising technologies offer continuous power • But some can’t handle large step loads and many are rather inefficient • Typically too expensive vs. batteries (for now!) • Supercaps (some) utilize KOH electrolyte with same disadvantages as batteries • Acidic hazards • Disposal concerns • Gassing on overcharge
Comparison with other storage devices(1) item Conventional Capacitor EDLC Battery (Lead-Acid) Battery (Li-ion) Energy density (Wh/kg) <0.1 0.2~10 10~40 40~80 Power density (W/kg) 10,000 ~100,000 100~5,000 50~130 100~300 Discharge rate ~0.1sec 0.1sec~1min 10min~10h 10min~10h Cycle Life >500,000 >500,000 200~2,000 ~10,000 Shelf Life 5~10year 10~15year 3~5year 5~10year Over discharge ○ ○ × × Environment ○ ○ × △
Comparison with other storage devices(2) Conventional Capacitor EDLC Lead-Acid Battery Cup bucket drum Water in the cup can be applied at one time but volume is not sufficient enough for fire fighting Not applicable Best option for fire fighting Not applicable Sufficient amount of water in the drum but can not be applied at one time for fire fighting EDLC is best storage device for charge and discharge of large amount of electricity in a short period of time!
Load high speed switch commercial power Sag compensation mode Inverter EDLC Dynamic Voltage Compensator (system) Back up Rated Output 10,000kVA Dip comp. time 1sec Rated Voltage 3φ 6,600V Operation On-line method Switch over No interruption (Less than 2msec) Storage EDLC Efficiency over 99% Module 600S1-70C-11P 292×600×395H EDLC Panel System(W:28m-H:2.6m-D:2.3m)
Application for Electric railway (system) Regeneration & Peak cut CAPAPOST(W:4.1m-H:3.1m-D:5.0m) EDLC Bank(600S1-70C×36P×8S)
Load fluctuation Electric Power system ~ Power constant junction engine generator (assume) junction + SG SG EDLC DE DE Load Load to supply Battery EDLC engine engine storage Storage generator generator 自立範囲 Power System Stabilizer (system) Peak cut & Regeneration Stabilize the sharp fluctuations by PSS Input transformer AC/DC EDLC 100kVA AC6600V 、