System reliability in 2012, excluding major storms, was overall better than or equal to statewide performance in 2011, and utilities met stray voltage testing and inspection requirements, according to the New York Department of Public Service (DPS).
The DPS presented its assessment of electric reliability performance in the state for 2012 in its “2012 Electric Reliability Performance Report,” given to the state Public Service Commission (PSC) on June 13.
According to the report, staff primarily relies on two metrics commonly used in the industry to measure reliability performance: the system average interruption frequency index (SAIFI or frequency) and the customer average interruption duration index (CAIDI or duration).
The performances of Consolidated Edison Company of New York (Con Edison), New York State Electric and Gas (NYSEG) and Rochester Gas and Electric (RG&E) improved slightly as compared with 2011.
Calendar year 2012 was by far the worst year for storm effects in the 24 years of staff recordkeeping, the DPS added, noting that Superstorm Sandy caused the overwhelming majority of the storm-related outages last year.
Of the more than 726 million hours of customer interruptions that have occurred since 1989, more than 23% – or 168 million hours – can be attributed to Sandy during October and November 2012. Sandy’s effects were focused on the downstate region, including the Hudson Valley, New York City and Long Island. In total, more than two million customers were affected by the event, the DPS added.
Beside Sandy, several other storms affected New Yorkers last year, including snowy wind events in January and severe thunderstorms in July, August and September. While those storms were excluded from the reliability performance calculations because they are circumstances over which the utilities have limited control, some spillover effect in the periods following the storm may have affected the overall performances, the DPS added.
With respect to individual utility performance in 2012, all companies met their reliability performance mechanism (RPM) targets except for Con Edison, which failed to meet several metrics.
The company attributes its failure to achieve its duration performance to underground cable and primary feeder failures as well as increased network interruptions and additional response times during Sandy, the DPS added. Outages caused by major storms are not excluded from network system performance measures under Con Edison’s RPM and the company is seeking exclusion of those storm-related outages from its network performance measures.
Con Edison also failed major outage RPMs related to the shutdown of 11 networks during Sandy and is seeking exclusion for those events on the “major storm” exclusion, the “catastrophic event” exclusion, which exempts any incident resulting from a catastrophic event beyond the company’s control such as natural disasters, and the “generation/bulk transmission” exclusion, which exempts any incident where problems beyond the company’s control involving generation or the bulk transmission system is the key factor in the outage.
“Hurricane Sandy was the worst storm in Con Edison’s history, five times worse than Hurricane Irene,” a company spokesperson told TransmissionHub on June 18. “We sought and received mutual aid from all over the country, and our men and women worked around the clock to restore service to customers. We have taken steps in the wake of this storm to harden our system to limit the number and duration of outages, and our storm hardening efforts will continue for years.”
The DPS said that Con Edison continues to implement various relief and reliability programs to improve its network system performance. Thus far, staff has noted a corresponding reduction in outages caused by equipment failures by 19%, reflecting those investments.
As a result of Sandy, Con Edison has increased its storm hardening efforts to protect the transmission, substation and distribution systems. The DPS also said that transmission projects are underway to upgrade the steel lattice towers, reinforce feeder runs to substations and replace line and dead end splices on transmission feeders. Those three projects would strengthen the transmission facilities making them less prone to failure during high wind events.
Several immediate storm hardening projects have been implemented for substations that are designated in flood zones, including sealing of troughs and conduits. The company has also increased its efforts to address the underground and overhead distribution system, including installing submersible transformers and network protectors, the DPS added.
NYSEG’s 2012 frequency performance was the best out of the last five years and it performed better than its five-year average in duration performance. The last rate case settlement agreement that the PSC approved included an increased number of vegetation clearing miles to be completed each year by the company, which the company exceeded in 2012.
The DPS further noted that NYSEG is working towards a full-cycle distribution vegetation management plan, which it expects will provide reductions in interruption due to tree contacts and improvements in restoration.
NYSEG should continue to focus on improving its distribution vegetation management program and reducing tree-related outages, the DPS added, noting that the company also continues its focus on proactive replacement of aging infrastructure, which it expects to yield continued improvement.
Encompassing the period from 2008 to 2012, NYSEG has expended nearly $80m on the transmission and distribution infrastructure reliability program, nearly doubling the budgeted amount of $42m.
RG&E performance in 2012 was consistent with its five-year averages in frequency and duration, and will continue its vegetation management efforts along distribution and transmission infrastructure, the DPS added.
The company continues to focus on underground cable replacement and other reliability projects, including pole replacement, for 2013, and is proposing a more aggressive vegetation management strategy along its distribution infrastructure.
The DPS also said that National Grid plc subsidiary National Grid USA performed slightly worse than its five-year averages in frequency and duration, although its performance is still within acceptable tolerances.
The company continues to address issues concerning reliability through various infrastructure improvement programs, including adding distribution automation infrastructure, and its existing inspection and maintenance program.
National Grid’s vegetation maintenance program continues to show overall progress, due in part to its enhanced hazard tree maintenance program, which identifies trees for removal outside of the standard tree trimming envelope.
Central Hudson Gas & Electric, meanwhile, had its best frequency performance of the last five years in 2012, with its duration performance about the same as the five-year average, meeting the RPM target.
While tree contacts continue to be the leading cause of interruptions, the company continues to improve as a result of its more aggressive vegetation management programs, the DPS added. Furthermore, Central Hudson is experiencing fewer equipment failures, which is credited to infrastructure replacement programs.
Orange and Rockland (O&R) also experienced its best frequency performance of the last five years in 2012, and its duration performance was better than the five-year average, the DPS said. Tree contacts and equipment failures are the leading causes of outages in the company’s service territory.
The DPS added that O&R continues to address those through infrastructure improvement programs such as installing reclosers and sectionalizing switches as part of its enhanced distribution automation program, the construction of new substations, enhanced tree trimming and selective undergrounding of critical overhead lines.
Con Edison and O&R are subsidiaries of Consolidated Edison (NYSE:ED). NYSEG and RG&E are subsidiaries of Iberdrola USA, which is a subsidiary of Iberdrola S.A. Central Hudson’s holding company is CH Energy Group (NYSE:CHG).