The potential for significant damages due to unpredictable flooding creates a need for this investigation. This particular plant has a history of utility trip occurrences, further necessitating this analysis.The purpose of this analysis is to further examine the situation and determine how to prevent over-topping under various flow conditions.
Objectives:
Objectives:
- Compile and organize data relating to power canal and hydroelectric units
- Create a model of the existing power canal to better understand the behavior of the canal under different scenarios, and serve as an instructional tool for operators in anticipating behavior/conditions
- Determine head gate water elevation height threshold that indicates weather eventual over-topping will or will not occur
- Determine locations where over-topping will occur
- Determine times at which over-topping will occur under different flow conditions
- Utilize model to determine if the use of a control device at the wicket gates alone will be sufficient to prevent over-topping of power canal
- Recommend actions that should be taken to prevent over-topping, and justify these with data from the model
ECRE has expressed interest in implementing a control device at the wicket gates to automatically re-open them a predetermined amount after a utility trip. In this case, powerhouse gates would open immediately after a utility trip occurs. This would allow water to flow through the powerhouse, and the turbines would be spinning. However, the hydroelectric generators would still need to be manually restarted by an operator, and would therefore be off immediately after the trip event (not generating electricity). If generators are off, the turbines may spin freely up to a certain point. When turbine speed exceeds synchronous speed (RPM), it strains the generator, resulting in damage being done to the equipment. Synchronous speed (rotational speed of the magnetic fields in the units) for the hydroelectric units is 40% of the maximum generation speed. Therefore the maximum amount that wicket gates may be automatically re-opened after a utility trip is 40%. The animation on the right shows a plan view of a wicket gate, intended to clarify how they operate. Control is driven by the two linear hydraulic motors. Red represents high pressure, and blue represents low pressure fluid within each cylinder. The wider the gates are opened, the more water flows to the turbine (in the center), and the more power can be generated. |
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