G534 - WTA 300B Excitation

4 days - 2.6 Continuing Education Units Awarded

WTA-300B Excitation System reliability and availability can be a matter of skilled routine maintenance activity and proficient troubleshooting capability. Proficient troubleshooting is greatly aided by a solid operational understanding of the excitation system. This course gives technicians and engineers the necessary knowledge to maintain, repair and calibrate the WTA-300B Excitation System by:

1. Using effective routine maintenance practices.
2. Knowing what checks may be performed on-line and how to perform these checks without causing an equipment shutdown.
3. Increasing the likelihood of accurate problem diagnosis by thoroughly understanding how the equipment operates.
4. Increasing the likelihood of accurate problem diagnosis by understanding any given circuit?s impact upon operations; ie., quickly linking the symptom(s) to the faulty circuit.
5. Verifying suspected faulty circuit by analyzing voltage levels and/or signal traces.
6. Understanding the necessary calibrations, after the faulty part has been replaced, including how the calibrations are performed.

HPC's WTA-300B Excitation System course makes heavy use of prints, on which the participants are encouraged to take notes. This provides a valuable reference for future use. In addition, the student manuals contain a complete description of the excitation system operation.

OBJECTIVES
Upon successful completion of this course the participant will be able to:

1. Discuss how an excitation system accomplishes voltage and VAR control.
2. Discuss the primary and secondary roles of an excitation system.
3. Discuss the major excitation system components, including limit and protective features.
4. Discuss the purpose and operation of the brushless exciter.
5. Discuss the purpose and operation of the Manual Voltage Regulator (Base Adjuster).
6. Discuss the purpose and operation of the boards in the logic drawer that comprise the Automatic Voltage Regulator.
7. Discuss the purpose and operation of each of the following circuits: Trinistat Power Amplifier., Firing Circuits., Blown Fuse Alarm, Excitation System Damping Board, Reactive Current Compensator Module, Maximum Excitation Limit, Overexcitation Protection, Minimum Excitation Limit, Field Supply Breaker, Automatic Ground Detector and Motor Operated Aduster Panels.
8. Trace a signal change through the WTA-300B Excitation System, given prints.
9. Discuss routine maintenance including what can and cannot be done on-line.
10. Discuss troubleshooting of the WTA-300B Excitation System, including expected voltage/signal levels at the boards.
11. For a given symptom, list the most probable fault location(s).
12. Discuss the options available to quickly narrow down the fault location.

COURSE OUTLINE

1. Introduction
2. Review of Fundamentals
   1. Fundamentals of AC Power
   2. Generator Fundamentals
   3. Excitation System Fundamentals
3. WTA-300B Overview
   1. Block Diagram
   2. General Description
   3. Excitation Switchgear Layout
   4. Trinistat Power Amplifier
   5. Trinistat Firing Circuit
   6. Regulator Logic
   7. Regulator Protection
   8. Base Adjustor
4. WTA-300B Detailed Discussion
   1. Trinistat Power Amplifier
      1. Components
      2. Operation of Power Amplifier Section
      3. Operation of the Pulse Transformer Module
      4. Operation of the Blown Fuse Alarm
   2. Trinistat Firing Circuit Assembly
      1. Components
      2. Operation of the Transformer Module
      3. Operation of the Phase Shifter Module
      4. Operation of the Input Module
      5. Operation of the Pulse Generator
      6. Operation of the Loss of Pulse Module
   3. Logics
      1. Components
      2. Operation of the Excitation System Damping Board
      3. Operation of the Reactive Current Compensator Module
      4. Operation of the Reactive Droop Compensation Module
      5. Operation of the Reactive Line Droop Compensation Module
      6. Operation of the Resistive Line Drop Compensation Module
      7. Operation of the Voltage Error Detector Module
      8. Operation of the Signal Mixing Module
      9. Operation of the Minimum Excitation Limiter
      10. Operation of the Timer Limiter Module
   4. Protection
      1. Components
         1. Operation of the Forcing Alarm
         2. Operation of Timing Module (Fixed Time Timer)
      2. DC-DC Isolation Transducer
         1. Purpose and Application
         2. Description and Operation
      3. Motor Operated Adjuster Panel
      4. Field Supply Breaker
      5. Automatic Ground Detector Panel
         1. Operation
5. Routine Maintenance
   1. On-Line
   2. Off-Line
6. Troubleshooting & Repair
   1. Six-step Troubleshooting Method
   2. Symptom Analysis
   3. Expected Voltage / Signal Levels
   4. Most Common Failures
   5. Post Replacement Calibration