Transient Analyses
Narrows Transient Analysis
The
Narrows Powerhouse is located on the Yadkin River in North Carolina and contains
four vertical Francis turbines operating at 33 MW each. The project was
undergoing a comprehensive upgrade including runner replacement. As the
owner’s engineer, Devine Tarbell & Associates, Inc.’s (DTA) staff was involved
in the planning and execution of this work, and was assigned as start-up lead.
DTA staff provided hydraulic calculations and performed start-up and commissioning testing on behalf of owner. A computer model of the water conveyance system was to be prepared and calculations were to be made to predict speed and pressure rise that would occur during transient events.
A thorough transient study was completed. This included preparation of the computer model of the water conveyance system, turbine and control parameters. Load rejection test results were conducted, and the results confirmed speed and pressure rise values as predicted by the computer model. This unit was successfully returned to commercial operation, without objectionable speed or pressure rise.