Integrating Variable Wind Power Using a Hydropower Cascade

In this paper, we examine the ability of a hydropower cascade to balance variability from wind power. We consider a coordinated hydro-wind system that satisfies a single power balance, and we use a real-time control scheme to optimize system operations such that wind and load curtailment is minimized. The control scheme considers system hydraulics (including dynamic tailrace elevations and water travel times) and system constraints. Generation from an individual hydropower plant is modeled using a convex piecewise planar approximation. We give results from a case study involving hydro and wind power in the Pacific Northwest region of the United States. The objective of this paper is to present a framework for evaluating how the regulation of wind generation affects hydropower operations. Our intention is to use this framework in future work to perform a systematic study of balancing capability across different hydraulic conditions, system constraints, and wind generation scenarios.