The 2010 SGS Transmission Reliability
Benchmarking Study
The SGS Study has set the standard for benchmarking
transmission reliability since 1995. The SGS Study utilizes 5+
years of raw transmission circuit outage data and applies
common rules to all systems to insure the highest integrity of
analysis and comparisons.
The SGS Study is the largest independent benchmarking
comparison forum for electric transmission reliability in the world.
Features of the SGS Study:
DELIVERABLES: A 300+ page Study binder, customized company-
specific Summary (30+ pages) and NERC TADS Supplement, electronic
data files and a 2 day participant conference (deliverables, CD). More
than 30 different reliability performance measures are provided at a
circuit-, voltage class- and system-level.
NERC TADS PERFORMANCE METRICS: The Study has a complete
section utilizing 12 of the 16 NERC TADS metrics (Transmission
Availability Data System) for AC transmission lines. Mandatory NERC
TADS reporting for Bulk Power systems took effect in January 2008, with
the first annual reports in Q3-2009. The SGS Study provides your
system an advance view of its performance under NERC TADS with
benchmarks to the industry and your peers, which are not provided in
any NERC reports View sample NERC TADS report.
SIZE: The completed 2009 SGS Study had 28 participating systems. The
2009 SGS Study had the following circuit totals:
2009 participants had approximately 487,000 MW peak transmission
load, serving an estimated 76 million distribution and wholesale
customers.
The 2009 SGS Study included approximately 54% of US Bulk Power
transmission based on NERC reported mileage (see participation map,
list).
EASE OF PARTICIPATION: Simply provide a down-load of raw
transmission outage data and circuit inventory (see data submission
example). There are no complicated surveys or spreadsheets to
complete. A low commitment of internal time and resources for
participants.
VALIDITY OF COMPARISONS: The Study pools raw outage data and
uses common methods process each participants and to screen major
event days (pooling data).
TIMELY RESULTS CONFERENCE: Results are presented at a 2 day
Conference on May 4-5, 2010 at the Turning Stone Resort in Verona,
NY (central NY state) at a closed participant conference. Includes
participant presentation about internal reliability management practices.
COMPREHENSIVE: Comparisons by voltage class against the industry
average, quartiles, geographic regions, self-defined PEER group and
individual systems (bar chart, trend chart).
GRANULARITY: Precise circuit-level performance measures for
reliability management decision support. Annual and multi-year
averages of circuit level performance.
CUSTOMER and DELIVERY POINT ANALYSIS: IEEE Std 1366 and
other reliability measures and benchmarking are provided for
transmission line outages affecting Customers or Delivery Points by
system, voltage class and individual circuits (example).
OUTAGE CAUSE ANALYSIS: Participant classify their internal outage
cause descriptions into nine Study categories. Analysis is provided at
the voltage class (bar charts, trend charts and tables) and circuit level
output.
CABLE: Comparison of cable reliability performance (voltage class,
individual circuits).
COMPLETE PERFORMANCE METRICS: The Study uses performance
metrics defined by NERC, IEEE and CIGRE working groups, plus
innovative reliability statistics (time between failures).
COST: Participation cost is determined by system size for transmission
owners. Participation is also available for ISOs, RTOs and Regional
Reliability Councils.
To view examples of typical SGS Study output and deliverables and a
discussion of Study applications, click on the following link to view PDF of
slides:
SGS STUDY SAMPLE DELIVERABLES and SLIDES (PDF)
There is a formal project proposal and data requirements documents
which are sent upon request in January.
The STUDY TIMELINE illustrates the data submission process, analysis
phase, conference and support.
2009 SGS Study Participant List
Listing of participants does not constitute an advertisement or
endorsement of the study. Participants are listed to provide an example
of the size and type of systems likely in future years.
- American Transmission Company
- Arizona Public Service
- Dominion Virginia Power
- Duke Power Company
- Entergy Transmission
- Exelon Corporation
- First Energy
- Florida Power & Light
- Georgia Integrated Transmission System
- Hydro One Networks
- Idaho Power Company
- International Transmission Company
- Long Island Power Authority
- National Grid USA
- Nebraska Public Power District
- New York Power Authority*
- Northeast Utilities
- NorthWestern Energy
- Oncor Electric Delivery
- PacifiCorp
- Pacific Gas and Electric
- Progress Energy
- South Carolina Electric & Gas
- Salt River Project
- Southern Company*
- Tennessee Valley Authority
- Tucson Electric Power
- Xcel Energy
There are 60+ operating companies (as defined as FERC Form 1
reporting units or public power agencies/coops)

Voltage Class
|
Number of Circuits
|
Circuit Miles
|
Load Serving (<230 kV)
|
12,773
|
180,150
|
Bulk Power (>= 230 kV)
|
3574
|
98,483
|
Total
|
16,347
|
278,633
|
|
The 2010 SGS Transmission Reliability
Benchmarking Study