Guide to Gas Turbine Training

There are a wide variety of gas turbines in service and planned in the power utility industry.  That variety includes:

• Age – from the early 1970s to today
• Manufacturer, both domestic (mostly General Electric and Westinghouse) and offshore (Siemens, Alstom, Mitsubishi, and so on)
• Type – “heavy duty” and aeroderivative
• Controls – mechanical hydraulic, analog EHC, contemporary digital, OEM and third-party retrofit
• Rating – from ~10 to over 300 MW
• “Accessories” such as air inlet cooling and fogging for wet compression
• Combustion systems – from no NOx controls to advanced Dry Low NOx (DLN) with lean premix on gas fuel a water injection on oil fuel
• Post combustion emissions controls
• Provisions for fast starting

One thing that is common to nearly all gas turbines is a high degree of automation as compared to steam turbines.  The startup sequence is virtually always completely automated in acceleration to rated speed.  For many gas turbines, the operators need only initiate the start sequence, turn on the automatic synchronizer after reaching rated speed to synchronize the generator, and set the load for the unit.  Normal shutdown is also automated.  Additionally, many CTs are operated remotely.

Another common characteristic of gas turbines is that they typically have modular construction with many auxiliaries, such as lube oil systems, that are provided by the gas turbine manufacturer on skid-mounted, enclosed packages.  The support systems not provided by the gas turbine manufacturer typically include post combustion emissions controls (e.g., Selective Catalytic Reduction – SCR systems for NOx control), fuel storage and forwarding, water treatment and demineralized water forwarding, electrical distribution, and service/instrument air for air-operated devices not supplied by the gas turbine manufacturer.

The documentation that is provided by gas turbine manufacturers, particularly for the controls, is often difficult to use, especially for operators.  In fact, to get the details of the controls for some gas turbines requires access to the controls programming for the gas turbine in question, and use of proprietary software from the gas turbine manufacturer.  Use of that software typically requires training.

Gas turbine manufacturers often offer training for their equipment, however that training is generally generic and confined to the equipment they supply.  The training typically does not cover auxiliary equipment not supplied by the gas turbine manufacturer.  This means that while the training is worthwhile, it does not meet all of the training needs of the plant staff.

There is considerable generic gas turbine training available from vendors other than the manufacturer, often in the form of computer-based training (CBT).  Typically this training is confined to the equipment supplied by the gas turbine manufacturer.  Also, this training is generally generic.  This is true even when the training is advertised as covering a common model of gas turbine, such as the GE FA.  There are many variations for this popular model, including:

• Controls – GE has provided Speedtronic Mk V, Mk VI, Mk VIe. Additionally some units have been retrofitted with modifications for fast starting and model-based control
• Combustion systems (DLN-2 & DLN-2.6, gas & liquid fuel)
• Air inlet cooling – variations include evaporative coolers, chillers, and inlet fogging/wet compression. Some unit have no inlet air cooling
• Generator excitation – EX2000, EX2100, EX2100e and earlier generation GE static excitation systems
• Emissions controls including both SCR and CO catalyst

Because of the high degree of automation for gas turbines, and the difficulty in learning the details of the gas turbine equipment, especially controls, many operators can operate as long as there are no problems, but when there is a problem, especially during the startup sequence, they are not in a position to resolve the problem.  The result can be what NERC calls an “attempted unit start,” and considerable cost.

Finally, the staff of gas turbine plants is small and typically not organized with a rigid division between operations and maintenance.  In many plants, the entire plant staff performs both maintenance and operations tasks.  This means that complete training includes maintenance and operations.

These factors present a challenge in providing comprehensive and effective training for gas turbine operators.  An effective training program requires extraction of the relevant information provided by the gas turbine manufacturer and integration of plant information for equipment not supplied by the gas turbine.

Improving and maintaining highest availability and minimizing attempted unit starts requires a plant staff that is well trained.  FCS has wide experience in developing and presenting effective gas turbine training programs.  Those programs are typically comprehensive, covering the entire plant rather than the gas turbine alone.  FCS has worked on gas turbines for most major vendors including GE, Westinghouse, Siemens, Alstom, Solar and Pratt and Whitney.  We have experience with old mechanical hydraulic controls and the latest digital controls, including model-based controls.  We have experience with aeroderivative gas turbines as well as heavy duty gas turbines ranging from units like GE frame 5 units rated at 15-20 MW to frame 9 units that are rated at over 250 MW.  We are familiar with new features such as those developed and implemented for fast starting.