Challenge:
Water is important for life, as everyone knows. What fewer people may know is just how important water is to the production of paper, something we use in almost every aspect of our life: Paper is approximately 90 percent water during the manufacturing process. International Paper’s plant in Georgetown, South Carolina, makes a lot of paper, which means that it also uses a lot of water: millions of gallons per day.
The plant, which was built in the 1930s and repurposed in the mid-1980s to manufacture bleached paper, runs 24 hours a day, every day of the year. Three generators—one of which is capable of producing 32 megawatts and two capable of producing 44 megawatts each to power the facility. That’s enough energy to supply the mill and the entire city of Georgetown in emergency situations.
For purchased energy, the facility relies on a 115,000 volt line, which runs through transformers that convert it down to 34,500 volts and then down to 13,800, 2,300 and 480 volts for facility use. When dealing with such high-voltage equipment, safety and reliability are more than important; they are vital, both for employee well-being and for productivity.
The water that is so critical to the mill is provided by pumps that are located 26 miles away. While we have an excellent track record at International Paper (we even remained operational during Hurricane Hugo), ensuring that the power source is reliable is no easy task. By combining two technologies—ultrasound and infrared—we met the challenge.
While I was familiar with using infrared (IR) technology to diagnose high-voltage issues, I knew nothing about ultrasound, until a forward-thinking former supervisor handed me an Ultraprobe and gave me a simple directive: “Learn how to use this.” So, off I went to a training course in Florida, and what follows below is an example of how ultrasound technology, compared with the IR methods I already knew, helped International Paper avoid big trouble.
Solution:
Ultrasound is now a regular part of our predictive maintenance program. Twice a year, I use the long-range module on the Ultraprobe 10,000 to run the length of the line and detect potential issues such as corona, tracking, and arcing.
During one investigation of the HV lines feeding the supply pumps, I noticed some darkening on a section of an insulator. Using infrared technology, I discovered that the darkening was a hotspot, registering close to 20 degrees Fahrenheit hotter than the ambient temperature. Digging deeper, I aimed the IR at the attached cable, which was connected by traditional U-style bolts, but found that it was at the correct ambient temperature. U-bolts, however, create a perfect environment for electrical discharge, which made me suspicious of the seemingly “normal” cable. The Ultraprobe 10,000 confirmed my suspicion: there was corona discharge.
We called the local power company, and a technician came to the substation to change out the jumper cable. Cables are wound very tightly in order to prevent electrical discharge; the conductor is made of aluminum and is encased in a steel jacket. This cable had become unwound, a phenomenon known as “birdcaging.” When a cable is birdcaged, there is significant electrical discharge between the steel outer jacket and the aluminum internal conductor. The power company’s technician, after examining the cable, concluded that it was not the culprit; the load was not sufficient enough to cause such extreme corona discharge. Instead, the fuses were at fault.
High-voltage fuses are shellacked with fiberglass (or sometimes porcelain) to prevent electrical discharge. However, after significant outdoor service, the encasement breaks down, creating a “fuzzy” fuse, and this creates a distinct sound that is easily picked up with ultrasound: corona discharge emitting from the thousands of “fuzzy” points on the fuse. Using infrared by itself would not have discovered this, but the combination of seeing the problem (with infrared) and hearing it (with ultrasound) accurately diagnosed it, and the faulty components were replaced.
Results:
Using ultrasound and infrared together has saved International Paper millions of dollars. The two technologies, both alone and together, are powerful diagnostic tools that help detect and avoid high-voltage issues before they can disrupt operations—or worse, endanger employees.
This powerful duo also increases reliability, enabling International Paper to continue to produce the paper that people depend on every day while keeping us profitable—in large part due to a visionary former boss who handed me something I had no idea how to use. We know how to use it now, though, and that gives us a huge advantage.
