TG504 – (GE) Steam Turbine EHC Mk-II Controls

TG504 – (GE) Steam Turbine EHC Mk-II Controls

5 days - 35 PDH Credits Awarded



The EHC System is divided into 3 major sections that involve the control of the turbine. These are Speed, Load, and Flow. This course explains the purpose of each input and output signal of a given section along with an operational description of its functionality with respect to the control of the turbine. After a thorough discussion of each section, the association of each section to another is explained to provide a working knowledge of the EHC System in that the attendee knows the HOW, WHEN, and WHY of the signals used to control the valves; signals used for testing the various components of the turbine; and signals used for safeguarding the turbine. Insight into the design criteria of the circuits, priorities for calibration, sequence of calibration, calibration techniques, and need for accuracy is given as only a HPC Certified Instructor can accomplish. Topics include:  Turbine Control Concepts, Prints and Documentation, Valve Actuators, Front Standard, AC/DC Power & Ground, Speed Control, Load Control, Valve Position Control, Standby Control, Trip and Monitoring. Has an upgrade been considered for your EHC Mark-II? If so, this course provides some useful information. When is an upgrade inevitable? What benefits are to be gained from an upgrade? Which vendor does one choose? How does one start in preparing for an upgrade? From the information gathered and learned from the Steam Turbine Controls Upgrade Seminar that HPC sponsors, these questions and more will be discussed. Recommended for Engineers and E&I Technicians.


Upon completion of this course the participant will be able to:
  1. Participants will be able to describe the relationship of all control components to each other component and the overall system using a block diagram.
  2. Participants will be able to demonstrate the ability to use GE prints and schematics.
  3. Participants will be able to describe operation of the individual steam valve control devices (Control Pac) and the front standard trip and reset devices.
  4. Participants will be able to describe the output of each major subsystem in terms of the inputs and all internally generated signals. Subsystems include Speed Control, Load Control, Flow Control, and Pressure Control.
  5. Participants will be able to demonstrate the knowledge needed to troubleshoot analog and logic control systems.
  6. Participants will be able to demonstrate the knowledge needed to evaluate the OEM Line-Up procedures to evaluate and recalibrate the various systems.

Course Dates / Location / Fee

See 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.

What you will receive

  1. 1 copy of HPC Technical Services' textbook, (GE) EHC Mk-II Steam Turbine Controls, as written by Harold Parker and revised by Mike Whisnant.
  2. A "Certificate of Completion" with 35 PDH awarded.

Course Outline


  • Valve Actuators: MSVs, MCVs, RSVs, IVs, Disk Dump Valves, Fast Acting Solenoids, Servovalves, Test Solenoids
  • Front Standard Operating Mechanisms: MSV, MTV, MLSV, MTPV, ELSV, MTSV, MTP, OTSV, ORSV, ORP, O/S Trip
  • Prints and Drawing Practices


  • AC/DC Power and Ground: Power Supplies, Automatic Switchover, Grounding Systems, and Monitoring
  • Speed Control Unit: Low Value Gates, Speed/Acceleration References, F/V Converters, Wobbulator, Backup Overspeed Trip, Trip Anticipator, Speed Control Calibration, and System Logic


  • Load Control Unit: Stop Valve Amplifier, Intercept Valve Amplifiers, Control Valve Amplifier, Load Reference Amplifier, Load Limit / Runback, Stage Pressure Feedback, FA / PA Circuits, Power Load Unbalance / Logic, Early Valve Actuation, Load Control Unit Logic, Standby Control, Speed Line Matching, Calibration Procedures, Plant Communications


  • Flow Control Unit: Admission Modes, Valve Position Units, EL vs. EF, CV Position Unit, Crack Points, Valve Loop Setup Procedures, Valve Test Logic, Main Stop Valve Logic, Control Valve Logic, Combined Valve Logic, AMS Discussions


  • Trip and Monitoring: Individual Trips, 125 VDC / 24 VDC Crossover Trip Bus, Front Standard Automatic Test Sequences
  • Line Up Instructions
  • Big Picture Schematic Discussions
  • Maintenance & Troubleshooting
  • Upgrading the EHC: Inevitable, Vendor Choice, Benefits Gained, How To Start Evaluation

Frequently Asked Questions

  • Will HPC Technical Services bring this course to our location for our personnel only? YES, call or email Stephen Parker, for a price quotation.
  • Will HPC Technical Services customize the presentation at our site to suit our particular needs?
  • Is HPC Technical Services' textbook available for purchase as a reference document? No, this course depends too much on print reading.
  • 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 perform a functional checkout and calibration of your control system during the upcoming outage OR provide troubleshooting support should it be required? Yes we can.  Call or contact Stephen Parker, for our rate sheets and any further information required.

Steam Turbine I&C Maintenance Certification

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,, for detail on this certification program.