Gas generator services for your power plant

The main driver for generator issues is thermal effects from load shifting.  When you need to start and stop the equipment often and you’re operating in partial load, the resulting load shift changes the thermal profile within the stator and the rotating field—which in turn causes the components to shift.  Here’s a look at some typical cyclic rotation issues on the rotating field.

With the shift toward more cyclic operation in the fleet, GE undertook an enhancement program to provide customers with a solution to reduce risk of forced outage, lower O&M costs and avoid premature rewinds. GE now offers cyclic duty packages for both the stator and rotating field windings.  Our patented “Flex Pack” offerings, for example, help reduce the negative effects of cyclic operation

One of the main sources of service problems on the generator rotor is the collectors.  Having a Collector Brush Monitoring system will aid operators in knowing if there is a potential problem before it happens.  GE offers a monitoring system to go along with our Enhanced Brush Holder Rigging system.

On the generator stator side, the insulated copper winding is the number one reason for service issues.  A Partial Discharge Analysis (PDA) is a great way to track and trend the health of your winding over its lifetime.  PDA tests can be done periodically, or on a real-time basis, depending on system options.  GE offers this option, along with others (like shorted turns monitoring and vibration detection) as part of the Generator Health Monitoring System.  If you would like more information, please contact your local sales representative for additional detail and pricing.

The main reasons for rotor rewinds are grounds, shorts, main terminal stud failures, high vibrations, thermal sensitivity, insulation migration and damage, and amortisseur migration and damage. If you unit is experiencing any of these issues, it’s probably time for a rotor rewind.

The top reasons for stator rewinds are ground, shorts, operating the unit outside of GE’s operations protocol, bar armor and/or insultation damage and degradation, collateral damage/FOD, and bar abrasion. If any of these things is happening with your equipment, contact us. We know what to do!

GE’s Generator Health Monitoring (GHM) offering can help avoid unplanned downtime by allowing you to make informed decisions based on accurate operational and inspection data. GHM is a fully integrated and modular remote monitoring suite available for any type of air-cooled, water-cooled, or hydrogen-cooled power plant generator that provides continuous inspection and condition assessment, as well as early identification of any issues. One of the most important things to monitor and test—which is part of our GHM offering—is the flux probe, so even if you aren’t taking advantage of GE’s Generator Health Monitoring, we would recommend doing periodic flux probe testing on your generator.

GE maintains a database of information on almost all the units in our fleet.  This allows us to generate predictive modeling data to help customers understand the risk levels of their units.  If you would like to get a closer look at your generator’s condition and start planning for any future maintenance needs, we would be happy to share this information with you. Contact your local sales representative today!

The life expectancy differences between a base-loaded unit and a heavily cycled unit is represented in the curve below.  The upper bound limit shows a unit with more of a base-loaded operating profile, while the lower bound limit represents a unit that has a heavier load cycle (daily stops/starts, greater than average running hours, part load operation, load shifting, etc).

In the early 2000s, the power producing industry had a significant number of power-producing machines installed to account for the substantial increase in energy demand.  As such, these machines are coming up to and passing the 20 years in active service milestone.  Predictive models are estimating the servicing of many these machine’s generators in the near future with many at the same time. 

In-order to prepare for this maintenance “bubble”, we are increasing our capacity in our shops as well as increasing the ready-to-serve inventory.  We are currently experiencing increased volume and over capacity at peak times.  If you wait to plan your maintenance, there’s a good chance for delays in-order to provide the services you need.  Plan and lock in your maintenance needs now!  Contact GE.