The Long Island Power Authority’s (LIPA’s; Uniondale, New York, US) overhead transmission and distribution system (T&D) is first in New York State for reliability, according to criteria used by the New York State Public Service Commission. This is the third year in a row that LIPA has achieved this distinction.
As an overhead electric utility, LIPA continues to lead New York in reliability performance. As of November 2001, LIPA had the best System Average Interruption Frequency Index (SAIFI) value for all overhead NYS utilities. The average LIPA customer went 15 months between service interruptions compared to 12 months for other NYS utilities. LIPA’s service interruptions are 20% less frequent than the statewide average.
As of November 2001, LIPA has the best Customer Average Interruption Duration Index (CAIDI) value for all overhead utilities in New York State. The average LIPA customer interruption was 63 minutes compared to an average of 105 minutes for other New York utilities. That equates to 40% less interruption time than the statewide average.
"LIPA has invested over $592 million over the last four years on capital improvement projects and upgrades to the T&D system and has budgeted over $317 million for 2002. All told that’s nearly one billion in capital spending for system-wide improvements," said LIPA Chairman Richard M. Kessel.
Kessel said that he expects that LIPA’s electric system will be stretched to its very limit this summer during any prolonged heat wave. He pointed out that last August, LIPA’s T&D system delivered a total of 4906 megawatts (MW) of electricity to the Long Island Control Area (LICA) setting a new record for electricity delivered on Long Island. During last summer’s heat wave, the loss of any significant T&D component could have pushed Long Island over the edge and into rolling blackouts.
Kessel added that during a 24-hour period beginning on March 21st of this year high winds of up to 50 MPH buffeted Long Island – yet, only 1611 customers experienced a service interruption resulting from this weather event. Six years ago, similar conditions would have resulted in over 25,000 customers losing electric service. It should be noted that on an average day for this time of year 1500 outages could occur for various reasons. Despite these high winds, LIPA’s 40,000 miles of overhead lines continue to deliver increasing amounts of electricity while insuring that Long Islanders experience fewer and shorter service interruptions.
LIPA has implemented four major initiatives to improve overall system reliability:
LIPA’s vigorous line clearance program plays a major role in the relatively low number of service interruptions. Every year over 90% of all electric service interruptions result from tree limb contact with overhead electric lines. During the last two and one half years, LIPA has spent over $50 million on its tree trim and Wire-Friendly Tree Program, which promotes the use of trees that will have a less adverse impact on LIPA’s electric wires, poles and other components. LIPA’s line clearance program trims tree branches away from electric lines, helps insure public safety, minimizes electrical interruptions and outages, and limits damage from severe storms. It also provides a zone of safety in which line workers can do their jobs, especially during storm events when restoration work is done under hazardous conditions.
Distribution Feeder Reliability
Each year engineers analyze and inspect the worst performing distribution feeders. These feeders are then updated and refurbished to improve reliability. This includes both overhead and underground circuits. This program considers the general condition of the poles, wires and cross-arms in the feeder, the lightning protection, wildlife protection, tree condition and type of construction.
Transmission System Maintenance
LIPA has inspected all of its overhead transmission lines and has implemented a performance improvement program for the overhead transmission system. This includes replacement of wire, improvements in grounding and lightning protection, and replacement of poles where necessary. LIPA is replacing a major portion of one of its major underground transmission cables that imports power from Westchester County to Long Island. LIPA has also upgraded much of its transmission system in central and southern Suffolk County. The transmission system in the Rockaway peninsula has also been significantly upgraded.
In 2001, LIPA revised its entire maintenance program for substations, increasing the frequency of preventive maintenance. Beginning in 2002, LIPA is implementing an industry leading Reliability Centered Maintenance program that will completely re-examine the maintenance needs in substations. Several substations have been added, significantly upgraded or replaced, including substations in Glen Cove, Rockaway Beach, Central Islip, Miller Place, Riverhead, Babylon, Peconic, Southold and Southampton. LIPA is undergoing a major reliability improvement project at its Ruland Road substation, which will significantly improve reliability for much of Nassau and Suffolk Counties.