Serious physical attack on US power grid comes to light

...The utility industry has been focused on Internet attacks, worrying that hackers could take down the grid by disabling communications and important pieces of equipment. Companies have reported 13 cyber incidents in the past three years, according to a Wall Street Journal analysis of emergency reports utilities file with the federal government. There have been no reports of major outages linked to these events, although companies have generally declined to provide details. "A lot of people in the electric industry have been distracted by cybersecurity threats," said Stephen Berberich, chief executive of the California Independent System Operator, which runs much of the high-voltage transmission system for the utilities. He said that physical attacks pose a "big, if not bigger" menace.
There were 274 significant instances of vandalism or deliberate damage in the three years, and more than 700 weather-related problems, according to the Journal's analysis.

Until the Metcalf incident, attacks on U.S. utility equipment were mostly linked to metal thieves, disgruntled employees or bored hunters, who sometimes took potshots at small transformers on utility poles to see what happens. (Answer: a small explosion followed by an outage.)

Last year, an Arkansas man was charged with multiple attacks on the power grid, including setting fire to a switching station. He has pleaded not guilty and is undergoing a psychiatric evaluation, according to federal court records.

Overseas, terrorist organizations were linked to 2,500 attacks on transmission lines or towers and at least 500 on substations from 1996 to 2006, according to a January report from the Electric Power Research Institute, an industry-funded research group...