1. “Free Critical Power” for Energy Efficient Data Centers
Presented by:
Henk Mulder
GE Critical Power 1
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

2. What is “Free Critical Power” ?
“ Free critical power” is the opportunity to reduce energy consumption in data centers by using the reliable utility grid power system to help minimize the power conversions in the critical power system, especially the UPS.
This “free critical power” is achieved with a multi-mode AC UPS (also called eco mode) that only converts power when the utility power quality is outside the voltage tolerance of the critical IT loads.
Multi-Mode UPS is UPS capable of delivering highly efficient and reliable power by intelligent fast switching (<2 ms) between Double Conversion (VFI) and Eco Mode (VI). 2
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

3. “Free Cooling” & “Free Critical Power”
Weather Maps
Cooling System
IT Cooling Specs
“Free” Critical Power
Utility Grid Power Quality
Critical Power System
IT Power Specs 3
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

4. Datacenter – Critical Power System
Utility/Power Critical Load %
99%
Critical Power System – High Reliability
= GE Product
Power Monitoring
Control System (PMCS)
Utility Grid
IT/Server Loads
Input
Swgr
UPS
Ouput Swgr
PDU
Xformer
Power Supply
Backup
Generator
Parallel
Switchgear
Energy
Storage
When
“100%”
Get
“100%”
“Free” Critical Power from Utility to the Load 4
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

5. How can an IT Server Ride-through a 20 ms outage with no voltage?
IT Server power supply
How can an IT Server Ride-through a 20 ms outage with no voltage?
How can an IT Server Ride-through a 20 ms outage with no voltage?
Source: Delta Products Corp Link
A capacitor is included as part of Switch Mode Power Supply (SMPS) The capacitor provides energy storage for a ride-through of ms during a complete voltage outage. 5
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

6. What Voltage Tolerance is required by IT Equipment/Servers?
The ITI (CBEMA) curve
What Voltage Tolerance is required by IT Equipment/Servers?
ITI CBEMA Curve - Defines voltage immunity of IT equipment with plot of voltage tolerance vs. time
Prohibited Region – events in this over voltage region may cause damage to IT equipment
No Damage Region – events in this under voltage region may cause IT equipment to stop operating, but no damage
Ride Through - No voltage (zero voltage) up to 20 ms is allowed on ITI (CBEMA) curve
Curve updated by EPRI & IEEE Std 446 in 2000.
Source ITIC: 6
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

7. CBEMA curve vs. disturbance
ITI(CBEMA) curve vs. disturbances 7
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

8. Power Conversion in Data Centers
Typical AC Critical Power System ... 3power conversions
Typical Critical Power System Efficiency
90-95%
Double Conversion UPS
92-96% 4
15kVac
400Vac
400Vac
400Vac 1
400Vac 2 3
Utility
MV/LV transformers
Switchgear
PDU
Equipment Efficiency
98-99%
“Free” Critical Power … 1 conversion with Multi-Mode UPS (eBoost)
“Free” Critical Power System Efficiency
97-98%
15kVac 1
400Vac
400Vac
400Vac
400Vac
Utility
MV/LV transformers
Switchgear
UPS w/eBoost
PDU
Equipment Efficiency
98-99%
99.0%
2-8% improvement in Critical Power System Efficiency 8
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

9. Traditional Double conversion
On-Line Double Conversion UPS keeps the rectifier and inverter in the circuit and under load, resulting in significant switching and heat losses
2.5-3% 3-4% % = % Energy Losses 9
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

10. e high efficiency (up to 99%) Boost fast transfer to inverter <2ms
What is eBoostTM?
"GE's eBoost feature expands a classic mode On-Line Double Conversion UPS System to a multi-mode UPS capable of maximizing operating efficiency commensurate with the stability of utility voltage and frequency.
GE's eBoost topology provides bypass line filtering along with keeping the UPS output transformer and filter capacitors energized to provide passive transient filtration and power factor correction while under critical load. This technology provides extremely fast switching between the UPS bypass line and UPS inverter as required, in less than 2ms.
Fast transfer time
LC filter
Efficiency up to 99% 10
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

11. Multi-Mode (eBoost) UPS in Parallel System
eBoost also Operates in Parallel Redundant Configuration
UPS Efficiency 99%
Parallel up to 6 UPS modules in eBoost high efficiency operating mode
Redundant Parallel Architecture (RPA) provides up to 4500kVA capacity
All Inverters will transfer in <2 ms, compliant with ITI/CBEMA curves 11
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

12. eBoost™ mode vs ITI(CBEMA) curve
Does eBoostTM mode voltage performance fit within ITI (CBEMA) curve?
ITI CBEMA Curve - Defines voltage immunity of IT equipment with plot of voltage tolerance vs time
Prohibited Region – events in this over voltage region may cause damage to IT equipment
UPS Performance
eBoostTM
ITI (CBEMA) Curve
Double Conversion
No Damage Region – events in this under voltage region may cause IT equipment to stop operating, but no damage
Ride Through - No voltage (zero voltage) up to ms is allowed on ITI (CBEMA) curve
Curve updated by EPRI & IEEE Std 446 in 2000. 12
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

13. Multi-Mode UPS (eBoost) Validation Testing
eBoost Limits
ITI/CBEMA Limits
Double Conversion Limits
Red dots are input captures
Blue dots are output captures 13
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

14. Transfer to inverter initiated
Error detection
UPS output sine-wave is continuously monitored.
In case of instantaneous waveform distortion, lasting at least 500us, the UPS initiates a transfer to inverter.
Load is transferred to inverter following:
Under/Over RMS voltage
Under/Over frequency
Waveform distortion (Error detection)
UPS returns to eBoostTM operation once bypass is back within tolerances
Transfer to inverter initiated
after 500 microseconds 14
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

15. Mains Failure (Power Outage)
Power outage on input mains caused by failure on electrical distribution
load is switched to inverter into 2 ms
load it supplied by battery
Utility - input voltage
Load - output voltage
L1,L2,L3 N Y Δ
UPS
Power supply in eBoost operation
Power supply during input mains perturbation
UPS output
Mains disturbance
Performances vs. CBEMA curve 15
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

16. Cleared fault at UPS input
Short circuit on equipment installed on input mains caused relative voltage drop limited on magnitude and time:
Input mains out of by bypass tolerance, the inverter is switched ON < 2ms
load is supplied by rectifier or battery
Load voltage remains within CBEMA curve
Utility - input voltage
Load - output voltage
L1,L2,L3 N Y Δ
UPS
Power supply in eBoost operation
Power supply during input mains perturbation
UPS output
Mains disturbance
Performances vs. CBEMA curve 16
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

17. Bolted fault (3ph-N) at UPS input
Bolted fault on input mains causes power outage with no energy available for the critical loads:
error detection
load is switched to inverter <2ms
Load is supplied by the battery
Load voltage remains within CBEMA curve
Utility - input voltage
Load - output voltage
UPS output
Mains disturbance
Performances vs. CBEMA curve 17
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

18. Voltage sag
Voltage sag is a voltage drop limited on magnitude ands time, typically caused by peak demand or start-up of large loads like motors:
error detection
load is switched to inverter <2ms
Load is supplied by the battery
Load voltage remains within CBEMA curve
Utility - input voltage
Load - output voltage
UPS output
Mains disturbance
Performances vs. CBEMA curve 18
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

19. High frequency voltage surge
Bypass choke + UPS capacitor = LC filter
The LC filter is able to smooth the high frequency surge coming from the input mains.
UPS input voltage
UPS output voltage
Performances vs. CBEMA curve
Mains perturbation
UPS output L C
Performances vs. CBEMA curve 19
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

20. Fault detection
eBoostTM mode is able to discriminate upstream versus downstream fault
in case of fault on load side the loads remain on eBoost mode
Upstream fault transfer to inverter
Higher short-circuit capability from input mains
Utility - input voltage
Load - output voltage
Load - output voltage 20
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

21. Multi-Mode (eBoost) UPS Case Study
(Field operating data from March 2010-April 2012)
eBoost Operating Experience
Category
Data
Comment
Launched
2010
2nd full year
# of Sites Tracked
>20 sites
Using primarily RM&D
Reliability
100%
No load interruptions
eBoost Availability
>92%
Averaging >8000 hrs/year/unit
Unit Operating Hours
>200,000
Growing operating experience
UPS
 UPS
eBoost
Double
Site
System
Output
Multi-Mode
Conversion
Operating
Locations
Configuration
Reliability
Operation
Hours
Comments on Site Operating Experience
Atlanta
2x300 kVA
100%
98% 2%
>15,000
Good utility power quality, unmanned site
Louisville
4x750 kVA
95% 5%
>14,000
Good utility power quality, summer peak
New Jersey
4x500 kVA
82%
18%
>12,000
Utility cap switching , working to minimize 21
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012 21

22. Multi-Mode (eBoost) UPS Case Study
Operating Experience Lessons Learned
Multi-Mode Reliability
Programmable Software
very high reliability (100% on tracked sites) and could exceed double conversion reliability with time
opportunity to optimize operation with programmable software (custom schedule, etc.). Some sites use software, some do not.
US Utility Grid Power Quality
Parts Life
U.S. utility power quality high and suitable for Multi-Mode deployment. Collaboration between utility, UPS OEM and end user can help increase availability
some anticipation of parts life extension (if de-energized) but too early to change recommendation on maintenance/parts life interval at this stage. GE will be tracking and updating.
Operator/Human Intervention
many sites not using due to site decision to disable due to lack of understand benefit (high) vs risk (low). Power savings not direct benefit to site team (don’t get evaluated on power/energy cost).
System Configuration
some system considerations (surge protection, power monitoring/metering, etc.) important to deploy.

23. Power Usage Effectiveness (PUE)
Total Facilities Power
Uninterruptible Power Supply
Generators
Power Distribution Unit
Lighting
Distribution Losses
Voltage Drop
Chillers / Pumps / AHU
Precision Air-Conditioning
Security
PUE =
= 1.53
Total IT equipment usage
Servers
Workstations
Storage Devices
Network equipment
Switches
Supervisory equipment 23
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

24. Impact of UPS Multi-Mode on PUE
UPS Double Conversion Mode
PUE = 1.39
UPS Multi-Mode (eBoost)
IT Equipmen t
IT Equipmen t
65%
72%
50-75% reduction in UPS losses
15-20% reduction in total losses
pt. improvement in PUE
3x reduction in UPS losses 24
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

25. Multi-Mode Energy Cost Savings
Typical Data Center Site Savings
UPS Global Fleet Estimated Savings
eBoostTM
** Equivalent to four (4) Nuclear Power Plants
50k square foot data center (5 MW load)
$.10/kW-hr power cost and 10 year life cycle
$310k annual energy savings
$3.1MM energy savings over 10 year life cycle 25
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

26. Green Grid Position on Multi-Mode UPS
Green Grid Data Center Maturity Model (DCMM) includes recommendation for UPS Multi-Mode (Eco Mode)
Technical presentation “Evaluation of Eco Mode for UPS Systems” at Green Grid Tech Forum in 3/ (on TGG website)
Upcoming detailed TGG white paper on UPS Eco Mode to help with industry understanding and adoption 26
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012

27. EPA Position on UPS Multi-Mode
EPA supporting “Multi-Mode” or Eco Mode as “innovative strategy” for energy savings in UPS
Operating time in Eco Mode (vs Double Conversion) varies with factors but primarily input power quality (esp. Utility Grid) and possibly human behavior
EPA ENERGY STAR uses 25% weighting for Multi-Mode (Eco Mode) and expected to increase weighting with site operating data 27
GE Proprietary. All rights reserved.
Copyright by General Electric Company
Nov 2012