WSEAS Transactions on Power Systems
Print ISSN: 1790-5060, E-ISSN: 2224-350X
Volume 13, 2018
Transmission Constraint Modelling in Hydrothermal Scheduling Using AC Load Flow Model under Deregulated Environment
Authors: , ,
Abstract: This paper addresses the modelling of transmission constraints using full AC load flow model in the context of Hydrothermal Scheduling (HTS) under deregulated environment including multiple objectives, day basis profit and emission. In practical, DC load flow or Optimal Power Flow (OPF) are used in HTS problem as being state of the art but both these techniques has severe cons like DC load flow Model being too erroneous and OPF consumes too much time especially for a deregulated system where time is in short supply. In addition to this, satisfying ramping limitation is highly complicated when using OPF to solve large transmission system. For this purpose in this research AC load flow model is adopted over DC load flow or OPF model and power distribution among the units of GENCOs (Generating Companies) is performed by unit commitment. As AC load flow model being considered, the intricacies regarding Slack bus is also needed to be handled. The concept of slack bus is born for logical representation of power system by virtually injecting the mathematical unbalances of the system model through that bus. But for a large system where the unbalances exceed slack bus boundary the overall concept tends toward impossibility. Moreover the concept lacks practicality for a problem where multiple inter-related time-intervals is involved as in case of hydrothermal scheduling. In this research the concept of slack bus is extended for more practical depiction of a HTS model in deregulated environment. As the complexity of the problem increases greatly for involving such convolution, a hybridization between Artificial Bee Colony and Grey Wolf Optimization algorithms, i.e. hybrid ABC/GWO algorithm (h-ABC/GWO) is proposed which merges the superior exploitation technique of GWO with highly diversified exploration technique of ABC to provide sufficient diversity in the search space of HTS in order to counter additional complexity and to enhance the speed for solving the HTS problem efficiently.
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Keywords: Deregulation, Optimization, hybridization, AC load flow modelling, Hydro-Thermal Scheduling, Slack Bus
Pages: 188-199
WSEAS Transactions on Power Systems, ISSN / E-ISSN: 1790-5060 / 2224-350X, Volume 13, 2018, Art. #19