Lack of communication may have played a role in last month’s massive blackout, but beyond that, hopes by legislators that they would find a key to strengthen the grid to prevent blackouts went unsatisfied Oct. 26. The hearing by the Joint Assembly and Senate Committee on Emergency Management and Assembly Utilities & Commerce Committee took place almost two months after the massive blackout in San Diego and Imperial Counties, as well as parts of Arizona and Mexico. It left 7 million people in the dark Sept. 8. Grid operators testifying at a legislative hearing in San Diego said they have not been able to determine the root cause. All they can conclude so far is that the blackout stemmed from a series of unanticipated events they’re still struggling to understand. Grid officials roundly dismissed the much-publicized notion that the error of a single utility worker in Arizona triggered the power failure. Early reports attributed the outage to a mistake by an Arizona Public Service employee who was working on a line in Yuma that brings power from the east to Imperial Irrigation District and San Diego Gas & Electric. The mistake caused the line to go down. California Independent System Operator president Steve Berberich told lawmakers the Southwest’s regional transmission system is designed and operated to withstand such a mishap without suffering a cascading outage. Berberich attributed the massive power failure to 20 distinct events that occurred in five separate balancing areas in an 11-minute period before the complete power failure (see sidebar). “That line going out by itself should not have caused this cascade of events,” Berberich said. “Something different happened than what we had ever modeled,” explained Mark Maher, chief executive officer for the Western Electricity Coordinating Council. The council coordinates grid operations across 14 western states and parts of Canada and Mexico. He said it would take WECC about four months to complete a “disturbance analysis” it plans to share with the California Public Utilities Commission. To get to the bottom of what caused the blackout, the state grid operator and other balancing authorities and parties formed a joint task force to review the incident. In addition, a joint Federal Energy Regulatory Commission-North American Electric Reliability Corporation inquiry is underway. Lawmakers voiced hope that the federal report would be made fully public, citing past reports on outages that were heavily redacted. Federal commission attorney Heather Polzin pledged the blackout report is to be public. She added that past reports under secrecy resulted from investigations into potential criminal activity causing blackouts. So far, criminal activity is not suspected, implied Polzin. The CPUC also is investigating the blackout, commission interim program manager Valerie Beck testified. She said the state commission’s initial impression about the blackout was that the five balancing authorities involved were not communicating with each other before the outage. Assemblymember Ben Hueso (D-Chula Vista) seized on the communications issue. He pressed grid officials to look into how possible lack of communication between the five balancing authorities may have contributed to the power failure once events started. Sen. Christine Kehoe (D-San Diego) specifically said she heard that Imperial Irrigation District was not fully communicating with the state grid operator when unusual things began to happen. Donald Robinson, president of Arizona Public Service--a balancing authority in its own right--told lawmakers his company quickly shared information about the line outage in Tucson. Imperial Irrigation District experienced what its general manager Kevin Kelly called “unprecedented” flows of power from the north that day through its system. Kelly said the irrigation district is cooperating in the various reviews of the outage, but did not comment on the degree of communication that occurred between it and other balancing authorities prior to blackout. Since the outage, on a voluntary basis the irrigation district began sharing telemetry data collected from its transmission system with the state grid operator. Both have their own management territories. The state grid’s Berberich noted that telemetry sharing with the district is one of the operational improvements his organization’s made since the event in an attempt to prevent future blackouts. He added that he couldn’t rule out that poor communication between control districts may have contributed to the outage. At this point, about all that is clear is that routine monitoring and information sharing by various grid operators failed to detect that the massive outage was imminent or pinpoint its cause. Routine data WECC gathers from the grid--which it analyzes for 5,901 possible contingencies every five minutes--did not point to any problem before the blackout, Maher said. To determine the cause-and-effect chain in the events preceding the outage will take time, he said, because of the massive amount of data grid operators must analyze. Likewise, before the blackout, Berberich said state grid operator measurements taken every four seconds showed there was plenty of capacity to handle anticipated fluctuations in demand and no apparent problems with transmission facilities. “We were operating in a position to absorb a considerable contingency,” he told lawmakers. Maher explained that the root cause may have involved factors not included in the routine contingency analyses WECC performs, such as an unusual power demand pattern, bad relay settings, or problems in generating plants. As part of their effort to track down the underlying cause of the failure, grid technicians are sifting through the settings of thousands of relays embedded in the massive transmission system, as well as data related to generation and power flows and demand. It will be at least two months before the task force publishes any preliminary report. Ultimately, the cause is unlikely to be known for several months, grid officials said, if ever.
