Manufacturing Tip: How to Accurately Refurbish Hydro Turbines and Generators

Information courtesy of Paper No. 059, HydroVision 2008 – Copyright HCI Publications, 2008

Traditionally, alignment of hydro turbines and generators is performed using both a plumb line and an optical level. The plumb line is hung down the center of the unit and is used to position all the components so that they are concentric and their axis is plumb (readings are taken with an electric inside micrometer). An optical level is used to set the components at the desired elevation.

The negatives to the plumb line is that electronic micrometer readings are very time consuming, are sensitive to outside influences, and the repeatability of readings between technicians is difficult to achieve. Negatives to the optical level are they can be affected by the vibration of neighboring units, and if the difference in elevation between the components is large, then multiple set-ups are required.

There is an alternative to these traditional alignment techniques. When Manitoba Hydro planned to refurbish its Kelsey Generating Station in order to reduce outage durations and construction effort, they investigated this alternative.

Manitoba Hydro investigated three-dimensional measurement systems before settling on a laser tracker measurement system. The accuracy, repeatability, and the time required to take measurements with the laser tracker system were proven to be superior to traditional methods.

The laser tracker functions by emitting a laser that is reflected off a target positioned at the point to be measured. As the operator moves the target from point to point and the light is reflected back to the tracker, the distance to each point is calculated.

Using a laser tracker reduced outage time by an estimated 2 to 3 weeks per unit overhaul and allowed the construction team to work more effectively and produce a better result. The laser tracker was so effective that it was used for significantly more applications than originally anticipated.

As you can see, a laser tracker measurement system can provide substantial savings in schedule and construction effort in both the refurbishment and new construction of hydro turbines and generators.

Read the entire white paper.
Read more about laser tracker technology.