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Transcript of -Distributed Generation - A Reliable Power Solution For The Digital Age? Dustin T. Smith Power...
-Distributed Generation -
A Reliable Power Solution For The Digital Age?
-Distributed Generation -
A Reliable Power Solution For The Digital Age?
Dustin T. Smith
Power System 2002 ConferenceImpact of Distributed Generation
Clemson, SCMarch 13-15, 2002
Project Development Manager
Sure Power Corporation
2002
TodayToday
Today: Key macro-economic trend – Everything is digital (digital economy)
Components that have been addressed: IT (networks & software)/Telecommunications (networks & software)/Equipment Manufacturers (reliability of components). Components that have not been addressed: Power
What Do We Want To Accomplish?
Collectively have a better understanding of Applying DG to Mission Critical Facilities.
Reinforce the definitions of common metrics.
Challenge barriers to wide spread use of Distributed Generation. Encourage evaluating Distributed Generation as an option.
Topic Items
Appropriate Use Of Metrics – Reliability vs. Availability vs. Quality
Power Issues Of The Digital Age
Critical Elements Of DG High Availability Power – Mission Critical Applications
Example Schematic - DG Mission Critical Application
Summary - Concepts To Remember
Electric Utility
Built for the Industrial Age (light bulbs and motors).
Ability to support Mission Critical facilities is different in every location.
Facilities
Facilities supporting digital commerce are a critical component of the final product (Integrate the value of Availability into Marketing Plan).
Integration of Product Marketing and Facilitates Planning/Design Groups in conjunction with the Business Plan – Complex Project.
Demands – Volume, Availability & Quality
Scaleable, High Availability (5 9s or greater), CBEMA grade (IEEE 446-1987) power.
Vulnerabilities - Complex systems are much weaker than their weakest link.
Digital equipment power sensitivity (example: eight milliseconds outside voltage curve for microprocessors & more than a 20% voltage deviation for four cycles for semiconductor fabrication = SYSTEM FAILURE). Even short down times equals huge losses. On-Going operations & maintenance are crucial.
Power Issues Of The Digital AgePower Issues Of The Digital Age
Quality - CBEMA CurveQuality - CBEMA Curve
Typical Design Goals of Power Conscious Equipment Manufacturers - CBEMA CURVE
(IEEE 446-1987)
0%
50%
100%
150%
200%
250%
300%
350%
400%
0.001 0.01 0.1 1 10 100 1000
Time in electrical cycles - Logarithmic Scale
Vo
lta
ge
Ex
cu
rsio
ns
(%
)
No
min
al
= 1
00
%
Half Cycle
0.5
ReliabilityReliability
Reliability
The Probability that a system or even a component will operate for a given period of time. Quality is a component of this metric.
Over time, reliability tends toward 0 (all components eventually fail).
For complex systems: Mission length must be known and is most useful for analysis of missions during which equipment may not be repaired or down for maintenance (missions of shorter duration).
R = 1 - Pf (Probability of Failure)
Over Time - All Components Fail
0
1
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Time
Rel
iabi
lity
Reliability ExampleReliability Example
Reliability of Emergency Diesel Generators
– Emergency Diesel Engine Generator Power System Reliability 1987-1993 Grant, G.M., et. al., Idaho National Engineering Laboratory, INEL-95/0035, February 1996
0.75
0.8
0.85
0.9
0.95
1
1/2 hour 8 hours 24 hours
Availability (Unavailability=Q=1-A)
The probability that a system will function at a future instant in time. Quality and Reliability are components of this metric.
Most useful in the analysis of complex, repairable systems with longer mission durations (does not necessarily require defined mission length).
Probabilistic Risk Assessment – Most useful tool in defining Availability (Redundancy/Spare Parts Inventory/SLAs/Staffing).
Utilizes historical performance data for individual components.
Provides specific probability of system availability in the future.
Over time, calculated results have been extremely accurate (I.e. nuclear industry).
Availability is the most useful metric for identifying power performance parameters for mission critical applications.
According to experts in the science of Probabilistic Risk Asseement1, achieving availability levels (in practice) above four 9s (99.99%), likely requires on-site distributed generation.
[1] Steve Fairfax, President of Mtechnology, Saxonville, Massachusetts, USA
AvailabilityAvailability
Application of the NinesApplication of the Nines
In The Digital Economy, Unavailability (1-Availability)
does not equal Down Time (Facility outage may be a magnitude
longer than the original power outage).
Nines Availability Unavailability
"one nine" 90% 10% 876 hours"two nines" 99% 1% 87.6 hours"three nines" 99.9% 1.0.E-3 8.76 hours"four nines" 99.99% 1.0.E-4 53 minutes"five nines" 99.999% 1.0.E-5 5.3 minutes"six nines" 99.9999% 1.0.E-6 32 seconds
Downtime
The PRA gives us an Availability Design Criteria. How do we apply it?
We must convert the system Availability/Unavailability
to a specific Probability of system failure!
Availability & Probability of FailureAvailability & Probability of Failure
0
10
20
30
40
50
60
70
80
90
100
99.9% 99.99% 99.999% 99.9999%
AvailabilityUnavailability
Cu
mu
lati
ve P
rob
abili
ty
of
at le
ast
1 F
ailu
re
10-2 10-3 10-4 10-5 10-6
99%
Assumptions:
16 hour mean time to repair
20-year operating life
The Traditional ApproachThe Traditional Approach
UtilitySubstations
BatteryBackup
UPSSystem
CriticalLoad
StandbyGensets
HVACSystemsHVAC
Systems
NormalLoad
EssentialLoad
Note: System availability 99.9% to 99.99%- Grid is prime source of power- Battery is short-term backup-Gensets are secondary source of power
High Availability DG SystemHigh Availability DG System
Note: Desirable System availability: 99.9999%-Prime source of power- Grid is secondary source of power
On-SitePower System
CriticalLoad
Chiller System
NormalLoad
EssentialLoad
( if available )
Utility
Chiller System
NormalLoad
EssentialLoad
( if available )
Utility
Critical Elements Of DG High AvailabilityCritical Elements Of DG High Availability
Basic elements of a high availability power system:
Redundancy
Allows system to operate when individual components fail.
Energy Storage
Maintains power flow to the critical load while additional power sources are dispatched during prime mover failure.
Switching
Detects failures in components (or even subsystems), and connects replacements (very complex and difficult).
All High Availability Designs must use these elements to achieve near-perfect operation with imperfect, real-world components.
Probabilistic Risks Assessment is a proven tool for determining the best balance of these elements and effecting the real-world system performance.
Mission Critical DG systems must be designed from the ground up with the goals, objectives and elements of High Availability in mind, not modified after-the-fact (pound-to-fit).
Additional Elements Of DG High AvailabilityAdditional Elements Of DG High Availability
Additional system performance requirements include:
Precise end user goals and objectives identified.
No single Point of failure
Example: RAID (Redundant Array of Independent Devices)
Independent redundant power paths
All generation available to all of the load, all of the time without switching.
No generation inter-dependencies
Eliminate all potential cascade failures
Design must allow for maintenance and repair (both routine and emergency) without disruption of power to the critical loads.
Benefits of DG In Mission Critical App.Benefits of DG In Mission Critical App.
Benefits of Distributed Generation in Mission Critical Applications
Dedicated operations and maintenance staff
Allows End User to manage their overall operational risk by allowing experts to handle the on-going production and delivery of Mission Critical power
True system High Availability
Efficiency (CHP Process)
Reduction in Environmental emissions
Capitol management (paying for on-site assets, not the Utilities transmission lines
Security
Autonomy/Control
Concepts To RememberConcepts To Remember
“Availability” is the most useful metric for evaluating the application of Distributed Generation power systems with respect to Mission Critical Facilities.
A formal, reviewable, rigorous design process such as Probabilistic Risk Assessment will dictate a design that ensures actual system performance meets the End Users long term system performance expectations (as well as meet business plan marketing objectives).
Table Reference: A Technical and Market Assessment of Premium Power in the Haverhill Cyber-District, Prepared For: Massachusetts Collaborative, Prepared By Planet-TECH Associates, January 2002
Concepts To Remember ContinuedConcepts To Remember Continued
“Availability” - Continued
These types of systems cost lest than the systems that do fail.
Once a system achieves High Availability in design, real-world limits such as common cause failures can be addressed.
Table Reference: A Technical and Market Assessment of Premium Power in the Haverhill Cyber-District, Prepared For: Massachusetts Collaborative, Prepared By Planet-TECH Associates, January 2002
First National Bank of OmahaFirst National Bank of Omaha
The reliability of the ‘six 9s’ computer grade electricity that Sure Power delivers isn’t a luxury for us at First National Bank of Omaha, it’s a critical difference over existing power arrangements that will substantially increase our computer uptime. The result is a tremendous leap in our competitive advantage. With Sure Power, First National can raise our customer’s service expectations while generating higher revenues.
Dennis C. HughesDirector of Property Management
First National Buildings, Inc.
© Copyright First National Bank of Omaha 1999
United States Patent 6,288,456 B1Date of Patent September 11, 2001
[Only DG - Mission Critical Installation with 3rd Party PRA Certification (Availability Higher than Grid + Back-up]