G401 – Turbine-driven Generators: Theory, Construction, Controls, Operations, Maintenance & Testing

G401 – Turbine-driven Generators: Theory, Construction, Controls, Operations, Maintenance & Testing

5 days - 35 PDH Credits Awarded



In most plants, the AC generator is the least understood, most “mysterious”, and most reliable component in the power plant.  Given all this, it should be understood that “There are NO SMALL PROBLEMS when it comes to your GENERATOR!”  Now is the time to close this knowledge gap.  In this course you will learn: Design, Construction, Operations, Safety, Testing, Inspection/Repair as well as disassembly/reassembly.  Don't be surprised.  Be prepared.  Register for this course today.  This course is designed for plant engineers who have a specific need to better understand generator equipment.  The course is intended for “experienced operational personnel”, plant technicians and plant engineers.  The course includes discussion on modern combined cycle applications as well as the older fossil and nuclear generators. Topics include: Generator Theory (Lite) • Systems Operation • Generator Construction • Generator Auxiliaries • Excitation Systems & Controls • Normal Operations • Abnormal Operations& Protection Concepts • Planning and Scheduling Generator Outages • Disassembly • Visual Inspection and Routine Maintenance Activities • Reassembly • Resistance Testing • Dielectric • Absorption Testing • DC Current Leakage Test • Dissipation Factor Test • Radio Noise Test • High Potential Testing • Ring Test • Polarization • Index • EL CID
  • How does a generator function?
  • Why is it designed as it is?
  • What happens if the generator is synchronized out-of-phase? Or any of the other abnormal conditions that may occur?
  • How can we avoid such an error?
  • How should the generator respond to frequency or voltage deviations?
  • Which electrical tests should be performed, how do you avoid accidents, and when should these tests be performed?
  • How do you repair commonly found mechanical problems within the generator components?
  • How can we avoid accidental injury when testing the generator?
  • What are the probable causes of grounded fields?
  • Why have we (recently) heard of hydrogen explosions? How do we avoid?
  • ...And the list of answered questions goes on!!

What you will receive

  1. 1 copy of HPC Technical Services' textbook, Turbine-DrivenGenerators: Theory, Controls, Operations, Maintenance & Testing, a $295 value, as written by Harold Parker, with technical support by via HPC's Advanced Generator Maintenance Seminar presenters, primarily AGT Services. This text contains a significant number of equipment photographs, graphics and data tables.  It is a valuable desktop reference in addition to being able to enhance the learning process.  This valuable text is available for purchase if you cannot attend.
  2. A Certificate of Completion with 35 PDH

Course Dates / Location / Fee

See www.TurbineGeneratorTraining.com for detail on the course dates / locations / and registration fees. HPC’s 3-4-2 policy applies:  Sign up 3 for the same course/date, pay in advance, and pay for only 2 (the 3rd participant is free)! HPC Technical Services reserves the right to cancel any course/seminar within 10-working days of the scheduled date.  Fees are 100% refunded or credited to another seminar (clients' choice) if HPC should cancel any seminar.  HPC is not responsible for non-refundable airline tickets or other travel expenses under any circumstance.


All HPC instructors are educated ‘experts’ on the subjects they teach, with years of relevant hands-on experience (typically 20+ years), and have proven instructional skills. Brief resumes can be looked up on HPC’s website, www.TurbineGeneratorTraining.com.


Upon completion of this course, participants will be able to:
  1. Describe how a generator functions. (Learn why and how the voltage drops with an application of a load and learn why and how the rotor speed and angle change as that load is applied).
  2. Describe active and reactive power. (Learn how active power is generated, how reactive power is generated, and how these loads are shared from one generator to another.)
  3. Describe the major components used in the construction of an AC generator.
  4. Learn how these components are at risk during mis- or abnormal operations.
  5. Explain operation and maintenance of the most common excitation systems.
  6. Explain how a speed governor alters generator output in response to a frequency deviation. (Learn why the speed changes when a load is applied. Learn what is the role of the governor is response to this speed/frequency change).
  7. Explain how the voltage regulator alters generator output in response to a voltage deviation. (Furthermore, learn why the voltage drops, how a voltage drop is detected, where it is detected, and how the voltage regulator responds as it does).
  8. Discuss the causes and effects of both voltage and frequency oscillations and the impact they each have on power system dynamics.
  9. Describe generator normal/safe startup and shutdown procedures.
  10. Describe why the generator synchronizing process is as it is. (Learn what are the results of not checking phase rotation, of mismatching voltages, of mismatching frequencies, and closing the circuit breaker out-of-phase.)
  11. Discuss abnormal generator operation and recommended actions for generator protection.
  12. Given an unfortunate abnormal condition, describe possible results to equipment and/or system.
  13. Describe the major activities associated with generator maintenance.
  14. Describe proper generator disassembly and reassembly sequences.
  15. Describe the procedures for cleaning generator components.
  16. Describe the procedures for inspection of generator components.
  17. Given any generator component, describe the types of damage that might be found, and what are probable causes of that damage.
  18. Describe the various repair methods for defective component condition.
  19. List all those electrical tests commonly performed on large AC generators.
  20. For each electrical test listed, describe the purpose of conducting that test; i.e., what are we looking for as a result of the test?
  21. Describe the procedures for the various generator tests.
  22. List and describe safety precautions for the conducting of these electrical tests.

Frequently Asked Questions

  • Will HPC Technical Services bring this course to our location for our personnel only? YES, call or email Stephen Parker, Stephen@TurbineGeneratorTraining.com for a price quotation.  Furthermore, HPC can customize presentation to suit your particular needs, making use of site specific construction drawings, procedures, P&IDs.
  • What is the cost for HPC Technical Service to deliver this course at our location? Well, of course that can vary, but generally speaking, if you're planning on having 6+ attend, when considering your T&L, it is to your advantage to perform the course at your plant (office).  You gain from the customization and price.
  • Can HPC Technical Services provide "Technical Assistance" in the planning and implementation of our outages? Yes we can.  Call or contact Stephen Parker, Stephen@TurbineGeneratorTraining.com for our rate sheets and any further information required.

Course Synopsis


  • Generator Theory: Armature Reaction, Resistive Loads, Inductive Loads, Capacitive Loads, Power Transfer and Load Angle, Reactive Power, Net Air Gap, Developed Torque, Watt and VAR Control, Power Transfer Between Generator Rotor and Stator
  • System Operations:  Structure of the Power System, Interconnections, Power Balance, Operation of the System, State of the Power System.


  • Generator Construction: Stator Frame, Core, Windings, End Shield, Rotor Body, Field Windings, Retaining Rings, Collector Rings, Diesel and Hydroelectric Differences
  • Excitation Systems, Voltage & Frequency Control: Speed Governor Response to Frequency Deviations, Automatic Voltage Regulator Response to Voltage Deviations, Manual Regulator, URAL, Impedance Compensator, Volts/Hertz, Maximum Excitation Limit, Transfer & Tracking, PSS, De-Excitation, Steady State Operation, Transient Conditions, Earlier Excitation Systems, Rotating AC Exciters, Alterrex, SCRs, Brushless Excitation Systems, Static Excitation Systems, SCPT, SCT-PPT, Bus Fed Exciters
  • Generator Auxiliary Systems:  Purpose and Operations of the Generator Hydrogen Control System, Generator Seal Oil System, and Stator Liquid Cooling System (as required).


  • Normal Operations: Preparation for Start-Up, Synchronizing, Load Changes, Use of Reactive Capability Curve, V-Curve, Performance Curves, Shutdown.
  • Abnormal Operations& Protection:  Relationships Between Operations, Protection and Alarms; Alarms, Protection when Off-Line, Tripping Methods, Protective Actions for Generator Faults and Abnormal Operations & Protection Recommendations: System Steady & Dynamic Conditions, Frequency Deviations, Voltage Deviations, Instabilities, Loss of Synchronism, Stator Overcurrent, Field Ground, Stator Ground Fault, Stator Phase-to-Phase Fault, Over Voltage, Over Volts-per-Hertz, Field Overheating, Loss of Excitation, Bearing Vibration, Synchronizing Errors, Motoring, Seal Oil System Pressure, Stator Coolant System, Local Overheating, Unbalanced Armature Currents, Breaker Failures, System Back Up, Voltage Surges, Transmission Line Planned Switching, High Speed Reclosing, Accidental Energization


  • Outage Planning & Scheduling:  Why Maintenance, Preparation, Tooling, Documentation, Pre-Shutdown Maintenance, Decision Making
  • Generator Mechanical Maintenance Activities:  Why Generators Fail, Special Tools, Spare Parts, Safety Precautions, Disassembly/Reassembly Procedure, Cleaning and Checklists.  Stator Visual Inspection to include; Loose Slot Wedges, Discoloration, Loose Punchings, Bar Vibration, Girth Cracks, Corona, Loose/Broken Ties, Liquid Connections, Air Baffles, Oil Deflectors, and Hydrogen Seals.  Rotor Visual Inspection to include Collector Rings, Rotor Journal Surface, Terminal Studs, Hydrogen Seal areas, Axial Flow Fans, End Turns, Field Slot Wedges, Retaining Rings.
  • Purpose of Generator Electrical Tests: Safety Considerations


  • Generator Electrical Tests: STATOR:  Winding Resistance, Insulation Resistance, Dielectric Absorption, Direct Current Leakage, Dissipation Factor Test, Radio Noise (Corona), High Potential Test, Ring Test, EL-CIDROTOR: Resistance Test, PI, Impedance Testing, Flux Pattern Test, Pole Drop, High Potential Testing, Air Gap Flux Probe Testing.
  • Certification Examination (not required, but recommended).

Generator Maintenance Certification

There are three levels of certification (all levels require this course):
  1. Engineer
  2. Mechanical Maintenance Technician
  3. Electrical Maintenance Technician
Those who attend this course are automatically qualified to take HPC Technical Services' Certification Examination.  This examination is offered at no additional expense to the participant.  An 80% passing grade is required.  The examination length will not exceed 2-hours.  Those who complete this examination will receive a revised "certificate of completion" that recognizes this accomplishment along with two-copies of a "To Whom It May Concern" letter that states their accomplishment.  (Two copies are provided, one for the participants' employer and one for the participants' personal file.)  Consult HPC's website, www.TurbineGeneratorTraining.com, for detail on this certification program.