Capability Curve Modeling for Hydro-Power Generators in Optimal Power Flow Problems

Abstract

With the growing emphasis on sustainability in the power sector, it becomes imperative to ensure that every component of the power system operates optimally and efficiently. More sustainable power system operation can be achieved by relying on accurate models that ensure resources, especially those from renewable sources like hydro-power, are utilized to their fullest potential. In many optimization problems based on optimal power flow formulations, the steady-state operation characteristics of hydro-power plants are modeled in an approximate manner, which could potentially lead to solutions that do not fully exploit their capabilities or even to solutions that jeopardize their stable operation. This work proposes a formulation for the complete capability curve of the plant, including the exact modeling of its generator stability limits. The ability of the proposed formulation to reproduce the plant operation boundaries is appropriately demonstrated through a test case. Furthermore, two approximate formulations commonly used in the literature are solved, highlighting their limitations. It is concluded that the complete representation of the capability curve can improve the quality of solutions provided by OPF-based problems.