Reliability
Significant Improvement:
Entergy’s reliability has improved significantly in recent years as a result
of the company’s efforts. The improvement has occurred since the company
introduced a new outage reporting system in 1998 that greatly increases the
accuracy of reported outages. In addition, Entergy significantly increased
reliability spending beginning in 1999. The improved reliability is especially
significant when considering the number and degree of adverse conditions that
affect Entergy’s service territory.
SAIFI and SAIDI:
Electric utilities primarily use two industry-wide reliability indices. The
System Average Interruption Frequency Index (SAIFI) captures the frequency or
number of interruptions experienced by a typical customer, while the System
Average Interruption Duration Index (SAIDI) captures the duration or total
number of minutes of interruptions experienced by a typical customer.
The Challenge:
Entergy’s reliability improvement gains have proven more difficult to attain
with each year that has passed since 1998. The easy fixes have been corrected,
so what remains to be solved are the more difficult reliability problems.
Entergy must continue to:
• manage the reliability improvement effectiveness of all the improvement
efforts
• fund the existing basic reliability improvement programs
• find ways to provide additional opportunities for reliability improvement.
Entergy Programs to Improve Reliability:
Entergy’s System 2004 SAIFI score has improved 48 percent since 1998. The
system 2004 SAIDI has improved 39 percent in the same timeframe. The increase
in 2004 is attributed to significant weather increases. The improvements can
be attributed to several actions Entergy has taken in recent years:
• Updating the TACTICS program, an acronym for Targeted Actions Centered
Toward Improving Customer Satisfaction. TACTICS seeks to uncover the root
cause of distribution devices experiencing repeated outages. The program finds
repeatedly offending devices and corrects the root causes of failure.
• Continued emphasis on the Targeted Circuit program, which concentrates
annual improvement work on the worst performing feeders across Entergy’s
system. A small number of poor-performing feeders can significantly impact a
reliability index. This program strives to concentrate work on the feeders
providing the greatest opportunity for improvement.
• Establishment of infrastructure / maintenance programs to focus on
maintaining a properly functioning electric distribution system. These
programs, which satisfy the requirements of the National Electric Safety Code,
consist of regular inspections and appropriate replacements of key equipment,
such as poles, capacitors, regulators, reclosers, underground cables, etc.
• Creation of the Backbone Feeder Inspection program, which provides for
inspection of the main circuit backbone on a cycle bases. This initiative
promotes a low cost “patrol and fix-what-is-broken” effort which prevents
waiting for a feeder’s performance to degrade before giving it reliability
improvement attention.
• Improvements to the company’s vegetation management process in order to move
away from reactive trimming and establish a system to trim each electrical
distribution feeder proactively, based on its own unique trim cycle.
• Entergy is exploring two new ways to enhance performance through technology.
First, distribution automation can detect an outage and perform intelligent
decision-making to reconfigure the system, cutting the outage time for many
customers to only a few minutes instead of the longer time needed currently to
manually reconfigure the system. Second, fault-monitoring technology can
pinpoint a fault’s location so response personnel can get there quicker and
reduce the outage length.
Entergy Reliability Compared with Other Utilities:
Like other utilities across the nation, Entergy’s reliability is adversely
affected by vegetation, lightning and animal contacts. But Entergy's
percentage of outages from these causes is nearly 25 percent more than for
other utilities across the nation. This is due in part because Entergy’s
service territory is located in the South and Southeast. In addition, Entergy:
• Serves many rural areas where population is sparse, requiring longer lines;
• Contains several of the most vigorous vegetation growth zones in the
continental United States;
• Is subjected to some of the most intense lightning activity in the
continental United States, exceeded in intensity only by the Florida peninsula;
• Experiences some of the highest rainfall amounts in the nation;
• Has one of longest vegetation growing seasons in the nation.
Despite these adverse conditions affecting reliability, Entergy has made
steady progress in recent years. And the company will continue to strive to
improve its reliability record. The best method to sustain reliability
improvement is to approach it from the long-term perspective, maintaining
reliability programs at a stable level, year after year.
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