Hydro-Electric Series

The objective of this course is to present and discuss the major constructional features of the hydro generator. A review of AC generation fundamentals is also included, as this is considered necessary for complete understanding.

Upon completion of this module, you should have an understanding of the following concepts:

• Constructional features of the vertical generator
• Function of the stator frame, stator iron core, and core laminations
• Stator windings and stator conductor arrangements
• Constructional features of the rotor
• Rotor poles, excitation current, and slip rings
• Thrust bearing arrangements, using tilting or spring-loaded pads
• Generator guide bearings
• Lube oil cooling
• High-pressure oil jacking system
• Protecting bearings against stray eddy currents, i.e. bearing insulation and shaft grounding
• The function and operation of the braking system
• Sources of heat loss in the generator
• Generator air-cooling system
• Stator conductor cooling water system
• Generator terminal equipment, i.e. generator terminals, isolated phase bus, PT’s and CTs
• Constructional features of the horizontal generator
• Review of AC generation fundamentals
• Production of the voltage sine wave due to the rotating magnetic field
• RMS values of voltage and current
• The relationship between frequency, speed of rotation, and number of poles.
• Three phase windings and connections
• Neutral grounding through resistance and/or grounding transformer
• Voltage relationships for the Wye connection
• The conditions required for synchronizing the generator to the power system
• Types of excitation systems:
  • Static excitation
  • Brushless exciter
  • Externally driven exciter
  • The traditional shaft mounted main and pilot exciter
  • Control of excitation