Pacific Gas and Electric Company (PG&E) is undergoing evaluation of another state-of-the-art tool to be used to inspect inside its large natural gas pipelines—the arteries of the system that heats and powers customers’ homes and businesses.
In an effort to continue growing its stringent inspection program, PG&E recently assessed Line 186 in Dos Palos, Calif. with an ultrasonic in-line inspection tool, a device which uses water, instead of natural gas, to move through the pipeline and identify any dents, gouges or scraps that may exist.
By moving through the pipeline in water, the new tool can be used in advance of a hydrostatic pressure test, the industry gold standard used to measure the safe operating pressure of natural gas transmission lines. The combination of modern in-line inspection technology and strength testing creates a more in-depth record that defines specific pipeline characteristics, as well as the specific operating pressure of the natural gas pipeline.
"As we work to make our natural gas system the safest in the nation, we are looking at new technologies that can help us get there," said Jesus Soto, PG&E's senior vice president of Gas Operations. "Combined with our already rigorous testing procedures, new technologies like this in-line inspection tool will give us valuable information about the health of our system."
Since 2011, PG&E has been rigorously inspecting pipelines to proactively ensure the safety and reliability of its gas system. PG&E has also strength-tested and replaced pipelines, adding remote-control and automatic shut-off valves that can stop the flow of gas faster in an emergency, and checking for leaks on a strict schedule.
PG&E has ramped up its schedule of interior pipeline inspections. Since 2011, PG&E has eight "smart pig" projects inspecting up to a total of 206 miles. The utility plans to inspect about 350 miles of pipeline using state-of-the-art in-line inspection technology in 2014.
PG&E's additional pipeline safety efforts since 2011 include:
• Replacing over 100 miles of transmission pipelines
• Strength-testing about 530 miles of pipelines using high-pressure water
• Automating 150 pipeline valves, allowing for remote control and, in some cases, automatic shutoff