Planning ahead

Make the most of your plant with generator maintenance

Your generator is the driving force behind your gas turbine equipment, so it’s important to make sure it will continue to run reliably and efficiently. The energy industry is changing rapidly, requiring plants to cycle in new and different ways to address the increase of renewable power. These shifts are placing ever-increasing stress on all power plant equipment, and generators are no exception. With many power plants now nearing the end of their operating capacity, it’s more important than ever to reach out to GE well ahead of your planned outage to address your generator maintenance needs.

Let’s say you have a high-risk generator, and you plan your maintenance well in advance. These are some of the benefits you could expect to realize:

  • Restored reliability up to 98.5%
  • Reduced risk of forced outage
  • Reduced generator unavailability by 3 months to a year (depending on the component)
  • Lifetime extension of up to 25 years

Generators 101: How a gas turbine generator works

We flip a light switch. We cook lunch. We charge our phones. We walk brightened cities at night. All this versatile power comes from generators big and small.  But how do they really work? Brush up on your generator knowledge with our “Generators 101” feature, which should answer all your generator-related questions—from what a generator is and how it works, to how they work with the gas turbine and why hydrogen is such an effective way to cool a generator.

Customer story

Breaking records in Thailand

GE’s generator services team completed Thailand’s first fast stator rewind of Sahacogen Public Company Ltd.’s GT-1 Generator at its natural gas co-generation plant in the Chonburi province. The upgrade took half the time designated for completion, a rare accomplishment for a stator rewind.

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reduction in completion time

17 days

Project completion

"

“We are very pleased to work with GE to help us successfully complete our generator stator rewind project so quickly, which allowed us to reduce the length of our maintenance outage and return the generator to service as quickly as possible.”

Mr. Thanawat Siwasoponpong

Co-generation power plant division manager of Sahacogen (Chonburi) Public Company Ltd.

Frequently asked questions

Learn more about generator services

What is the biggest challenge that cycling has caused?

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.

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What are some recommended generator upgrades for peaking units?

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

Download the Flex Pack fact sheet

What features should generator operators consider for improving reliability on heavy cyclic operations?

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.

What are the most common issues that could require a rotor or stator rewind?

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!

What are some predictive maintenance techniques that can help assess the condition of my generator?

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.

How does GE model and control the risk of generator assets?

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!

What is the difference in life expectancy between cyclic, steep ramping generators and base load generators?

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).

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Considering the large number of gas turbine units coming into their major maintenance cycle, what is GE doing to increase capability to help meet the coming demand?

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.

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Take a closer look at our generator solutions.

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Get an inside look at a generator fast stator rewind

Learn what a generator condition assessment can do for you

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