CAUGHT THE FAULT IN TIME

When a hot smell from one of the generators was found at the Rocky Reach Hydropower plant in Washington, Chelan County PUD feared what the extent of the damage would be.

Rocky Reach is Chelan PUD’s largest plant; it provides energy for several million people throughout the Pacific Northwest, making it an important source of renewable energy. If the stator winding had failed, the breakdown could be very serious.

The operators immediately stopped the unit. They found a burned group jumper in the winding and even though the system had not been built by us, they called the engineers at GE for assistance.

ROCKY REACH BROUGHT BACK FROM THE EDGE WITH QUICK ACTION

Carrying out repairs on a hydro generator is a bit like surgery: every plant is different and each one is located in a unique ecosystem that lives and breathes around it.

This challenge in particular was highly technical and required dextrous and swift action from GE’s engineers, who used GE’s ‘Pit-Stop’ option for generator rehabilitation to get Rocky Reach back to peak production fast.

After a day of observation and diagnosis, the problem turned out to be a weakness in the stator winding.

Due to the unique non-Roebel single turn coil design of the generator, these weaknesses had led to overheating. Following the assessment, the teams dug a little deeper to see if there were any other potential weaknesses. There were two stator coils that needed to be replaced to make sure no more faults occurred.

The GE team worked like a Formula 1 pit stop crew to replace the damaged coils and return the unit to operation.