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Mesa transformer explodes; affects 100,000 homes, businesses by Jim Walsh, Ryan Randazzo and John D'Anna - Jul. 1, 2011 12:00 AM The Arizona Republic A fire at a power substation in east Mesa set off a cascade of electrical failures Thursday that left more than 100,000 homes and businesses without power on a sweltering summer afternoon. Service had been restored to many by late evening. But today will bring new questions about whether service in the area can keep air-conditioners running for an afternoon of even higher temperatures. Thursday's problems began with a fire in an electrical transformer. Though the fire was doused, the extra load placed on other stations led to failures throughout the afternoon. Blackouts hit nearly every area of Mesa and Apache Junction at various times, forcing hospitals to use emergency generators and prompting companies to send thousands of workers home early. Business took a hit as stores and theaters closed, and staffers at nursing homes worried about their most vulnerable residents as the Valley's official high reached 105 degrees. SRP officials estimated that 100,000 to 150,000 homes and businesses lost power at one time or another throughout the day. Officials said they expected most service to be restored by midnight Thursday. As of 10 p.m., there were still an estimated 22,500 customers without power. City officials opened the Mesa Convention Center as an emergency shelter Thursday evening for anyone who needed to escape the heat. Doug Noble, 84, a retired Maricopa County sheriff's deputy, has heart trouble and grew concerned as the temperature reached 100 inside his east Mesa mobile home. He drove to the shelter for respite. "I'm glad this place was here, and I'm glad they have cold water," he said. The fire The fire started about 11:45 a.m. at the Thunderstone substation near Power Road and University Drive in Mesa, SRP spokesman Scott Harelson said. Spokesman Jeff Lane said that the transformers use a type of mineral oil for cooling and that the oil was likely what burned. SRP officials said they don't know what caused the fire, but Mesa Fire Chief Harry Beck said substation fires usually are caused by a surge somewhere on the power grid that damages the transformer. Fire crews could not put out the fire for three hours or more because the power lines first had to be shut down, then grounded to remove static electricity, which can pose a threat to firefighters, Beck said. "The fire itself was rather small and contained in an area where there were not a lot of other things to burn," Beck said. "Once we had the electrical current under control, we put out the fire rather quickly." Of the station's four transformers, only No. 3 caught fire. But although the transformers are designed so that a fire on one does not affect the others, all four were shut down, Harelson said. As the blaze sent billowing plumes of smoke across east Mesa, customers continued to get electricity from SRP as it was rerouted through other substations. But about three hours after the fire started, at 2:11, another SRP substation tripped offline. The Rogers substation northeast of Stapley Drive and University apparently could not handle the demand from all the power being rerouted around the burning Thunderstone station, Harelson said. "It proved to be more load than those transformers could handle," he said. An additional 15,000 customers get power from Mesa's city-owned electric utility. Their power is delivered through the same substation, and they also briefly lost service. SRP began to restore power to the substation, but workers had to manually close electrical switches in several neighborhoods to restore power, which left many people without power into the night. Outages across town Falcon Field Municipal Airport in Mesa was forced to suspend operations for several hours and divert traffic to other airports after the control tower lost power, and nearby Boeing was forced to cease operations for the day and send 4,000 workers home. Mesa City Hall lost power for about 45 minutes before it was restored about 3:30 p.m. At Caffe Boa Bistro near Power and McDowell roads in east Mesa, owners worried that pricey hand-cured meats could be in danger of spoiling. "We're losing business. It's killing us because Thursdays are pretty good for us," Jay Wisniewski said. Larger businesses were hit hard, too. Movie theaters were forced to refund tickets, and the 160,000-square-foot Costco at U.S. 60 and Sossaman, the largest in Arizona, closed for the day and sent its employees home. The failure knocked out traffic lights, but Mesa police said only two minor accidents were reported. A key concern was with area hospitals, many of which were forced to go to generator power for most of the afternoon. No surgeries or emergency-room services were affected at Banner's Mesa hospitals, however several surgeries at Mountain View Medical Center were postponed. Power went out about 2 p.m. Thursday at Banner Baywood Medical Center and Banner Heart Hospital. The two hospitals were running on generators. Several elder-care facilities were doing their best to cope with the heat. The Citadel Care Center, a nursing home on East Broadway Road, was still relying on a single generator and waiting for a second to arrive just before 6 p.m. to run fans and swamp coolers. Employees hung sheets over the windows to block the sun. Residents of the Orchard Active Senior Living Complex, near Greenfield Road and Main Street in east Mesa, congregated outside during the failure to avoid their steamy apartments. "I'm worried about the people who are on oxygen," said 64-year-old Marilyn Suiter. Bracing for today SRP could ask customers east of Loop 101 and north of U.S. 60 to conserve power today if the utility is unable to make needed repairs before the peak energy demand in the afternoon, Harelson said. SRP workers hoped they could activate the No. 1 and No. 4 transformers at the Thunderstone substation overnight. But if the smoke damage to the No. 2 transformer is too severe to have it running by Friday afternoon, the utility could ask customers to reduce their power use to avoid a blackout, he said. That likely would include a request for people to turn up their thermostats so that air-conditioning demand is reduced. SRP never asked customers Thursday to reduce their usage to minimize the risk of an outage. The North American Electric Reliability Corp. and Federal Energy Regulatory Commission can levy civil penalties to utilities that fail to meet reliability standards. Harelson said it is unlikely Thursday's event will trigger an investigation because of the nature of the accident. Republic reporters John Genovese, Matt Haldane, Angelique Soenarie, Art Thomason, Caitlin McGlade, Gary Nelson and Laurie Merrill contributed to this article.
Mesa transformer fire knocks out power to more than 80,000 in East Valley Posted: Thursday, June 30, 2011 3:25 pm Staff and wire reports East Valley Tribune An estimated 50,000 homes in northeast Mesa and Apache Junction have power again but 30,000 others still are without electricity due to a transformer explosion in east Mesa that drew fire crews from Mesa and Phoenix. At least two other substations throughout Mesa were overworked when power was shifted during the fire. The resulting outage affected traffic signals at many intersections and also struck businesses and city offices in downtown Mesa. Other parts of the city were experiencing intermittent power outages and rolling blackouts. The areas affected are predominately Dobson Road to the east of the city limits and from U.S. 60 to the northern city border. Salt River Project officials said they hoped to fix the problem by 10:30 p.m. Thursday. The utility company activated a plan to dispense ice at four Mesa grocery stores at 7 p.m. The Grand Canyon Chapter of the American Red Cross also opened a cooling center at the Mesa Convention Center, 201 N. Center St., with cold drinks and snacks for those affected by power outages. "We are not dealing with any increase in heat related incidents due to the power outages," said police spokesman Sgt. Edward Wessing. Mesa police officers were directing traffic at major intersections and only two collisions had been reported. Dark traffic signals should be treated as stop signs, according to police. The Salt River Pima-Maricopa Indian Community has also experienced power outages. The town of Fountain Hills said it had been notified by Maricopa County's emergency management department that SRP had announced possible rolling blackouts in response to the Mesa transformer fire. The outages began minutes after the fire broke out at the Thunderstone substation, according to SRP spokesman Scott Harelson. He said outages could increase due to the demand for power with the summer heat. “We had some degree of confidence that customers would not be impacted by the fire, but after we shifted all the energy to other substations, it overtaxed them and they started shutting down to protect themselves,” Harelson said. “We are working very hard to restore the power to customers.” According to SRP, one of the substation’s four transformers exploded about 11:40 a.m. Thursday, causing black smoke that could be seen for miles to rise from the facility northeast of the intersection of Power Road and University Drive and southeast of Red Mountain Park. The smoke originated from the burning of mineral oil that circulates within the transformers to keep them cool, according to Jeff Lane, an SRP spokesman. The three remaining transformers were shut down to protect them and the firefighters as crews faced a challenging situation with a blaze that could not be put out with water. In less than 30 minutes, customers in eastern and northeast portions of Mesa and Apache Junction flooded SRP’s customer service lines with complaints. Fire crews doused the fire with foam from a specialized truck. Crews had it extinguished in slightly more than an hour, Harelson said. The cause of the explosion was unknown and SRP crews were on scene working to restore power to customers. Officials said it was not known when power would be restored and that it could be out for as long as three hours or more. “The explosion could have been caused by the heat — we don’t know, yet,” Lane said. “Sometimes, transformer explosions are caused by equipment failure. It’s got some burning out to do with the amount of mineral oil that was inside the transformer that cools it off.” A small mobile home adjacent to the substation was destroyed by the fire caused by the explosion, Lane said. Falcon Field Municipal Airport in Mesa was forced to suspend operations for several hours after the tower lost power. Mesa City Hall also reported losing power for about 45 minutes Thursday afternoon. After a cleanup, SRP will replace the transformer, which costs about $4 million, and conduct an investigation into what caused it to explode. Harelson said the investigation should take about two weeks. The Associated Press contributed to this report. • Contact writer: (480) 898-6533 or msakal@evtrib.com |