Schneider Electric and PNM Team to Modernize Substations
By John Blaylock, Schneider Electric
Switchgear provide protection for the grid, and over time require upgrades to protect those workers who venture into those electrical substations, too. Upgrades are also needed to ensure system reliability and ultimately reduce unplanned outages and downtime.
Following is a case study from utility Public Servce Co. of New Mexico (PNM) and Schneider Electric, which teamed up on a project to modernize PNM’s switchgear to meet modern electrical standards.
Now more than ever, today’s “always on” wired, digital environment relies in part on a dependable, electrical grid. For years, PNM, like many electric utilities, maintained and extended it switchgear equipment lifecycle due to budget limitations, the rising cost of downtime and other factors.
In 2013, PNM made the decision to upgrade its old circuit breakers-some dating back 50 years or more-and eliminate asbestos-containing materials from its Albuquerque-area substations. Asbestos was formerly used by many electrical equipment manufacturers for its insulating property and resistance to electrical current and fire.
“The main drivers for the start of this project were to eliminate worker exposure to asbestos as well as increase reliability and reduce maintenance costs by going to a vacuum breaker technology,” said Mike Prescott, substations craft supervisor at PNM. “Eliminating asbestos exposure provides health benefits to employees and reduces compliance costs for the company.”
The utility, which serves more than 500,000 residential and commercial customers in New Mexico and parts of Nevada, turned to Schneider Electric’s Electrical Distribution Services team for help. Schneider Electric disposed of the utility’s aging breakers, installed a cost-effective direct replacement solution in 276 new medium-voltage circuit breakers, and safely removed asbestos-containing materials in more than two dozen substations over five years. PNM is budgeting to replace additional legacy circuit breakers at substations throughout their electrical system.
“They wanted the safety and reliability of modern equipment,” said Skip Hicks, Schneider’s senior services sales engineer who inked the original contract. “PNM was proactive in looking for a solution for their aging infrastructure before it became a big problem.”
PNM’s Prescott, who supervised the breaker installation and asbestos abatement, said that Schneider Electric’s turnkey solution, existing designs for their switchgear equipment-with more than 150 available-and customer service set the company apart from the competition.
“They actually shipped a breaker to us to get hands-on with it and see its components; a very thoughtful move on their part,” he said.
Modern switchgear = more reliability, less maintenance
The average lifecycle of a circuit breaker is about 30 years. Some of the breakers PNM disposed of dated as far back as the late 1950s. Replacing the old ones with new breakers meant that PNM not only enhanced equipment reliability, but also lowered costs for maintenance and monitoring.
|Magnum medium-voltage circuit breaker|
Installing new switchgear, however, usually means that the existing conduits above and below the old equipment must be moved, which is a laborious and expensive process.
Schneider Electric omitted this time-consuming step through a direct replacement solution that left the original footprint intact. PNM’s eight different types of medium-voltage circuit breakers were replaced with Schneider Electric’s Magnum direct-replacement breakers, which fit with any brand of medium-voltage switchgear. Magnum circuit breakers work with existing breaker compartment components and rack into a switchgear-lineup with the existing compartment cells. The original bus/structure needs no modification.
“We chose to replace only the circuit breakers instead of a complete switchgear replacement mainly for cost and reliability considerations. The switchgear cubicles have few moving parts and were generally in good repair, so there was no major reliability improvement to gain by doing a complete replacement,” Prescott said. “Replacing an entire switchgear would become a month-long project, where we could do a complete breaker replacement in five days.”
In addition to installing dozens of new circuit breakers, Schneider Electric oversaw the safe removal of asbestos-containing materials in some of the PNM substations. It subcontracted an experienced and licensed asbestos remediation company in Albuquerque to remove and dispose of the affected material, which included dust and debris from some of the old circuit breakers.
|Worker removes asbestos from old circuit breaker|
During removal, the asbestos abatement professionals worked in accordance with OSHA standards and sampled and monitored the air to ensure a safe working environment.
The safe and quick removal and disposal of asbestos enabled the installation of the new circuit breakers in an organized and timely manner-a factor especially important when downtime needs to be as minimal as possible.
“They were able to get up to speed very quickly and enabled them to be very responsive,” said Prescott.
PNM’s investment to upgrade equipment and its commitment to a safe working environment will pay dividends through a more reliable, secure and easier to maintain system for its many commercial and residential customers throughout New Mexico and beyond.
Work on the multi-million-dollar project is expected to be completed in 2018.
John Blaylock is vice president, modernization and consulting services, US Services, for Schneider Electric.