APS power grid has endured 9 minor acts of sabotage in recent years

More than 350 physical or cyber attacks have been recorded in recent years on the nation's power grid, including nine acts of sabotage on equipment owned by Arizona Public Service Co., according to records obtained by USA Today and The Arizona Republic.

The nine incidents recorded in reports to the U.S. Department of Energy involving APS equipment all took place in 2013-14, and officials at the utility said they were mostly in rural areas.

None is thought to be any more serious than vandalism, said Ted Geisler, APS director of power operations.

"In no case was there an impact to customers," Geisler said. "We don't feel in any case there was an impact to reliability."

Salt River Project did not report any incidents.

Utilities have been under increased scrutiny for their security measures in the wake of reports of cyberattacks on the grid, and a particularly troubling event in April 2013, when multiple people are thought to have shot up a San Jose, Calif. substation and caused significant damage, though not a blackout.

The APS incidents were less serious, though two involved people shooting firearms at utility infrastructure, Geisler said.

"None of them I would consider beyond minor," Geisler said. "An example is, we come across a transmission tower, and some of the bolts at the bottom of the tower are missing ... or someone tried to shoot an insulator ... we will find bullets stuck in a conductor, the actual line itself."

He said none of the nine events reported to DOE threatened major power outages because of the way the power grid can be routed around equipment under repair.

"There is no single point of failure for the grid," Geisler said.

Following the San Jose event, regulators at the Federal Energy Regulatory Commission and North American Electric Reliability Corporation issued new regulations for power substation security.

In Arizona, regulators at the Arizona Corporation Commission asked the state utilities to explain what additional security measures they were taking to protect the grid.

Utilities were reluctant to share many details with the media, though they met privately with regulators to discuss the matter.

"We have increased security at substations since that event," Geisler said. "We are working closely with utility neighbors in accordance with the newly developed NERC standards to install substation security devices."

He declined to say how much APS is spending to meet the new guidelines.

Salt River Project shared its written response to regulators last year with The Republic, but would not disclose what was shared in conversations with regulators regarding security.

"As the nature of threats to our electric system has changed over the years, SRP has changed its approach to security in order to keep pace with those threats," that utility said in response to the regulators' questions.

SRP spokesman Jeff Lane said SRP has seen few physical threats to its infrastructure, the most notable being some teenagers drinking beer by Roosevelt Lake who tried to damage a power line a few years ago.

Reporting on the incidents to the DOE appears inconsistent among utilities. While APS reported nine events, SRP, which shares service in metro Phoenix with APS, reported none. Other utilities show similar discrepancies. For example, Colorado had just four reported events, while Utah utilities reported 25 incidents.

SRP spokesman Scott Harelson said determining a potential threat is subjective.

"For example, we have experienced incidents at various substations that we have determined are the result of copper theft and not an attack on the system," he said. "There is a difference nationwide in how utilities are reporting these various incidents."

One incident in Arizona that appeared to be more than vandalism took place in June last year at Tucson Electric Power Co.'s Valencia Generating Station in Nogales.

The FBI investigated an "incendiary device" found next to a 50,000-gallon diesel tank at the power plant. The event caused minor damage and no injuries, as the diesel did not ignite. The attackers may not have known that diesel has a high flash point and is difficult to ignite.