The Dyanmics of Pumped Hydro Storage with a Pelton Wheel and Bypass: Response and Revenue

Open Access
Author:
Francis, Zachary Ryan
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Horacio Perez Blanco, Thesis Supervisor
  • Sean Brennan, Honors Advisor
Keywords:
  • Mechanical engineering
  • Hydropower
  • Pumped Storage
  • Dynamic model
  • Simulation
Abstract:
When coupled to multistage centrifugal pumps, Pelton wheels can closely follow steep generating and pumping ramps. Dynamic simulation is an excellent tool for establishing the boundaries within which a pumped hydro storage (PHS) system configured with a by-pass can operate. An impulse turbine, a synchronous machine, a hydraulic torque converter and a three-stage centrifugal pump, connected to the same shaft, constitute an advanced design to meet the unpredictability of wind and solar (W/S). The constant speed turbine is modeled via needle valve flow control to balance the shaft torque to meet the load. The pump is simulated based on turbomachinery equations, as to ascertain the torque required to absorb variability. The torque converter couples the pump to the generator shaft, and can lock in at a predetermined slip. The synchronous machine follows the net load in generating or pumping, meeting the grid operator specifications. The penstock model (800m, 6.5 km), meets requirements to avoid steep pressure excursions. A sufficient net positive suction head (NPSH) is assumed for the pumps and stored water mass is accounted for. The system can seamlessly switch from providing to storing power to/from the grid. An important question for PHS is to ascertain what revenues can be accrued by the enhanced flexibility of the response of the subject technology. For the grid operator setting, the plant is simulated to provide frequency and voltage regulation in order to meet a prescribed schedule for generation and storage. The prices applied are for both 2011 and 2012, and within those years, the revenues for typical spring and summer months are calculated for a 150 MW plant. Those revenues are used to complete a present worth analysis for three separate operating strategies.