Optimal Load Flow in AC/DC Power Grids: A Heuristic Approach using PSO Algorithm

The main objective of this pre-project is to study the optimal load flow problem applied to a proposed hybrid AC/DC transmission network, based on conventional iterative methods and applying a heuristic method (PSO) to solve the FCO problem.

Due to advances in Power Electronics, with the Voltage Source Converter (VSC) it is possible to have independent control between active and reactive power flows (AYAD, 2020;CHAGAS, 2022;IRNAWAN, 2020;WIGET, 2012). The VSC allows supplying positive or negative flow and thus regulating the system voltage. For larger and interconnected systems, Line Commutated Converter (LCC) technology is used, given its ability to transport power in the order of GW per pole. In hybrid systems, converter stations have the ability to control active and reactive power flow, however when temporary or permanent faults occur, the dynamic behavior of nonlinear components alters the load flow and, consequently, causes instability in the transmission network. AC/DC hybrid (BANDEIRA, 2018;LI, 2016;MACHOWSKI, 2020;SAUER, 2018).
Look up details 844 / 5,000 Translation results Translation result In the quest to optimize the results of a load flow problem, new optimization methods have been applied for better performance, speed and accuracy of analyzes with low computational cost SANTOS, 2017;SHAWLIN, 2022;SILVA, 2020). The Particle Swarm Optimization (PSO) method is one of those methods that in recent years has been widely applied to solve the OCF problem. The PSO, in addition to being easy to implement, with primitive computational structures and mathematical operators, has a low computational cost. Basically, the algorithm seeks the optimal solution by changing the trajectory of the particles in the population, and for that, the velocity and position of each particle are updated (BAHRANI, 2016;SAMA, 2020;SABER, 2012).
To meet this high demand for hybrid transmission networks arising from the increase in converter stations and the presence of several Distributed Energy Resources (RED) that imply different scenarios along the already condensed system of conventional generations, such as hydro and thermoelectric, it is -an analysis of the load flow problem (PFC) applied to the hybrid transmission network is necessary, since the loads, devices and DC sources must be modeled and implemented and incorporated into the conventional AC flow problem (CHAGAS, 2022;HOTZ, 2020;MEEGAHAPOLA, 2022;MOHAMMADI, 2020).
Thus, this pre-project seeks to implement a hybrid transmission network and apply the traditional iterative methods of solving the PFC, such as, for example, the Newton-Raphson (NR), and then apply a heuristic method, such as, for

A. Main Objective
The main objective of this pre-project is to study the optimal load flow problem applied to a proposed hybrid AC/DC transmission network, based on conventional iterative methods and applying a heuristic method (PSO) to solve the FCO Qeios, CC-BY 4.0 · Article, September 6, 2023 Qeios ID: H4B769 · https://doi.org/10.32388/H4B769 2/7 problem.

B. Specific Objectives
The specific objects to reach the general object are: Implement a hybrid AC/DC transmission network from model systems from the Institute of Electrical and Electronics Engineers (IEEE); Apply conventional iterative methods for solving a flow problem load on the hybrid network; Apply the PSO heuristic method to solve the PFC applied to the proposed network; Perform computer simulations for open source methods such as GNU OCTAVE and MATPOWER; Compare performance, convergence and results between conventional methods and the heuristic method.

III. Methodology
A bibliographical review will be carried out on linear and transversal themes to this pre-project through books, databases of magazines, periodicals and newspapers specialized in Electrical Power Systems, of national and international relevance, in addition to dissertations and theses. During the preparation of this pre-project, the candidate began his research on the subject, as presented in the Bibliographical References.
Computational simulations will be produced about the proposed hybrid transmission network for comparison purposes between conventional iterative methods and the heuristic optimization.
There are currently two approaches used to solve the FCO: mathematical programming methods and heuristics. In the mathematical approach, the goal is to find good quality solutions and convergence, in general, depends on a starting point. The approach by heuristic methods is seen as an algorithmic (computational) structure that can be applied to optimization problems and with few modifications, can be applied to a specific problem (BAHRANI, 2016;SABER, 2012;SAMA, 2020).
Heuristic methods have been researched to solve the optimal load flow problem. Although they are promising techniques, their practical application is currently faced with products on the market that use mathematical models, signaling a vast field of research and development. Twenty (20) hours per week will be spent on research -part-time, with the support of the employer, who provided a statement releasing the candidate to attend classes in the periods dedicated to postgraduate studies, as per the attached statement. In addition, it is expected to take 2 (two) subjects per semester, and the subjects Quality of Electrical Energy (2020.2), Power Electronics (2021.1) and Power Systems (2021.2) have already been taken at PPGEE/UnB.
The following tools will be used for the development of the work: Computer with Intel® Core™ i7 processor, 4.70 GHz (64-bit) and memory 16 GB RAM; Computer programs (GNU OCTAVE and MATPOWER) for simulations.