Optimal Day-Ahead Joint Energy and Reactive Power Scheduling with Voltage Dependent Load Models

This paper presents the pool-based day-ahead optimal scheduling of joint energy and reactive powers. The traditional social welfare objective which consists of benefit function of customers and cost function of real power generation is modified to include the cost function of reactive power generation. The realistic voltage dependent load modeling has been employed in this paper. The investigations clearly bring out the unsuitability of conventional single objectives such as social welfare maximization, loss minimization due to reduction of load served. Hence, the multi-objective optimization is essential in this context. This paper proposes several objectives such as social welfare maximization, loss minimization, load served maximization and voltage stability enhancement index; which can be judiciously combined as per the needs of the operating condition. The effectiveness of the proposed approach is tested on IEEE 30 bus system and the detailed simulation studies have been carried out with constant and voltage dependent load modeling.