The 2015 SGS Transmission Reliability
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.
In 2015 the SGS Study represented:
- 14 Transmission Systems (13 US, 1 Canada)
- 32% of US/Canada circuits (based on NERC TADS 2010)
- 30% of the US/Canada bulk power circuit miles (based on NERC TADS
- Represents 35% of total non-coincident total US peak MW load in 2007
(the all time US peak, EIA statistics)
Features of the SGS Study:
DELIVERABLES: A 300+ page Study, customized company-specific
Summary (30+ pages), Extended Summary 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.
SIZE: The completed 2013 SGS Study had 20 participating systems and
had the following circuit totals:
2014 participants had approximately 301,121 MW peak transmission
load, serving an estimated 45 million distribution and wholesale
The 2013 SGS Study included approximately 48.5% of US/Canada Bulk
Power transmission circuits based on 2010 NERC TADS (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
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 1 day
Conference during mid-May 2015 in Dallas, TX at a closed participant
conference. Includes participant presentations about internal reliability
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
CABLE: Comparison of cable reliability performance (voltage class,
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. 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.
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 and is competitive with other independent benchmarking forums.
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
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.
2014 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.
There are 30+ operating companies (as defined as FERC Form 1
- American Transmission Company
- Arizona Public Service
- Entergy Transmission
- Exelon Corporation
- Georgia Integrated Transmission System
- Hydro One Networks
- International Transmission Company
- Nebraska Public Power District
- NorthWestern Energy
- Oncor Electric Delivery
- Pacific Gas and Electric
- Salt River Project
- Tennessee Valley Authority
- Xcel Energy
reporting units or public power agencies/coops)
||Number of Circuits
|Load Serving (<230 kV)
|Bulk Power (>= 230 kV)
The 2015 SGS Transmission Reliability