Engineers at GE Energy Connections have developed a digital radiologist which ensures that a grid’s substations, control rooms and transmission lines all work fine and in tandem.
Morocco’s national utility, the Office National de l’Electricité et de l’Eau Potable (ONEE), was the first to make use of GE’s new technology.
Using digital X-ray technology, GE gave ONEE’s aging circuit breakers a thorough checkup to make sure they were fit to protect and stabilize the grid.
Industrial-strength circuit breakers are like the valves of the heart. They control the ebb and flow of electricity and protect the substation against damage from power surges. Some circuit breakers also help limit reactive current in a network.
Reactive current smooths the flow of electricity, but it is like cholesterol: Too much of it in the line can restrict that flow. Limiting reactive current ensures a healthy flow of “good” electricity through the line and also prevents overheating.
In order to evaluate the health of these circuit breakers, utilities must physically open them — a process that requires disconnection from the grid for between three and five days per circuit breaker.
A circuit breaker in a 400 kV air-insulated substation is approximately 6 meters (18 feet) tall and has up to six poles that inspectors traditionally have to take down to assess. The process costs the company precious man-hours and potential revenue.
So, what if a utility could peer inside a circuit breaker rather than open it up for inspection? Thibaut Mauffrey, engineering manager at GE Power’s Grid Solutions. realized it could, using the same digital X-ray technology GE Oil and Gas has been using to inspect pipelines for the last 10 years.
Unlike classic X-rays, digital X-rays have filters that can enhance the picture quality and accurately capture the dimensions inside the circuit breakers. These images enable specialists to pinpoint a problem and propose the appropriate remedy on the same day.
ONEE planned a one-day outage from the grid for each of the four circuit breakers they were checking. Within about half a day, the GE machine had produced its images, a specialist had reviewed them, and ONEE got to know that only one of the three units needed work.
Having now seen digital X-rays used this way, Mauffrey says he and his team will be proposing this option for other customers also.