ORPF procedures for voltage security in a market framework

The paper deals with the automatic procedures used for the definition of voltage profiles to be adopted in the operation of bulk power systems with the aim of optimizing both the economic and security issues. After reviewing the most important automatic algorithms for optimal reactive power flow (ORPF) existing in the technical literature, some new ORPF procedures are proposed. They are based on modern optimization techniques and on a new formulation of the objective function tailored for the operation of power systems in a deregulated framework. The final aim of the paper is to demonstrate the effectiveness of ORPF procedures for the critical evaluation of the working point of power systems obtained from the day-ahead market auction. Furthermore, the tests reported show that, even at the day-ahead stage of energy market, it is possible to define the optimal voltage set points for generating units to be adopted for hierarchical voltage control in real time operation.