Technical Paper 2
Modern Approach to Generator Stator Temperature Control on Load-Following Hydro Generators
Published Date: June 28th, 2017
Presented at HydroVision International 2017
James Volk, P.E., PMP
VP of Engineering
SEGRITY LLC – USA
Eric Wolfe, P.E.
Director of Special Projects at South East Alaska Power Agency – USA
Control Systems Analyst – Independent Consultant – USA
Hydro generators in Alaska often experience great load swings while they meet the power and frequency control demands of small islanded systems. Stator temperatures can suddenly drop and cause condensation during these load swings if cooling water is not automatically controlled in a limited range.
This paper discusses the operational and technical aspects of converting a manual, penstock-driven cooling water system to a stator temperature set point-controlled system that utilizes pumps and control valves. The project had the following goals: flatten stator temperature swings without limiting the full rated range, reduce cooling water drive head and flow to thereby gain generation, increase stator life, and increase operator awareness regarding performance and stator life.
Specific Areas of Discussion:
• Project scope
• Operational considerations: stator temperature set point and allowable variance, condensation, training, SCADA integration, and backup system design
• PID control for steady state and rapid load change
• Unexpected control problems: valve actuation variable dead time and hysteresis
• Measured overall economic benefit