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Publications

Publications by CPES

2015

Specialized Genetic Algorithm of Chu-Beasley Applied to the Distribution System Reconfiguration Problem Considering Several Demand Scenarios

Authors
Souza, SSF; Romero, R; Pereira, J; Saraiva, JT;

Publication
2015 IEEE EINDHOVEN POWERTECH

Abstract
This paper describes the application of the specialized genetic algorithm of Chu-Beasley to solve the Distribution System Reconfiguration, DSR, problem considering different demand scenarios. This algorithm is an approach inspired in the natural selection and evolution of species. The reconfiguration problem of distribution networks taking into account different demand scenarios aims at identifying the most adequate radial topology of a distribution system assuming that this topology is used for all demand scenarios under study. This search is driven by the minimization of the cost of energy losses in the network along a full operation year. The performance of the algorithm is evaluated considering test systems having 33, 70, 84 and 136 buses and a real system with 417 buses. The obtained results confirm the robustness and efficiency of the developed approach and its potential to be used in distribution control centers.

2015

Static Transmission Expansion Planning using Heuristic and Metaheuristic Techniques

Authors
Gomes, PV; Saraiva, JT;

Publication
2015 IEEE EINDHOVEN POWERTECH

Abstract
This paper describes a hybrid tool to perform Static Transmission Expansion Planning, STEP, studies and its application to the Garver6-Bus academic system and to the Southern Brazilian Transmission equivalent real system. The developed STEP tool integrates two phases as follows. The first one uses Constructive Heuristic Algorithms (CHA) to reduce the search space, and the second uses Particle Swarm Optimization (PSO) to identify the final solution. This hybridization between CHAs and PSO proved to be very effective and shows good performance to reduce the size of the STEP search space and to identify good quality solutions. These are relevant issues given the combinatorial nature of investment problems leading to the explosion of the number of alternative plans, one of the greatest difficulties faced in this planning problem.

2015

ELECTRICITY DAY-AHEAD MARKETS: COMPUTATION OF NASH EQUILIBRIA

Authors
Carvalho, M; Pedroso, JP; Saraiva, J;

Publication
JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION

Abstract
In a restructured electricity sector, day-ahead markets can be modeled as a game where some players - the producers - submit their proposals. To analyze the companies' behavior we have used the concept of Nash equilibrium as a solution in these multi-agent interaction problems. In this paper, we present new and crucial adaptations of two well-known mechanisms, the adjustment process and the relaxation algorithm, in order to achieve the goal of computing Nash equilibria. The advantages of these approaches are highlighted and compared with those available in the literature.

2015

Economic Evaluation of Generation and Storage Solutions in Low Voltage End User Installations

Authors
Soares, RA; Saraiva, JT;

Publication
2015 12TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
Storage technologies are expected to assume an increasing relevance in the next few years, given the widespread number of available options, the possible applications and the reduction of investment costs. Therefore and apart from the well-known hydro pumping stations, the installation of storage is being considered as an increasingly viable option namely in distribution networks and also in end user installations. This paper reviews the recently passed Portuguese legislation on self-consumption and details a model to evaluate the economic interest of installing batteries together with PV panels according to several possible business models. The simulations suggest that the tariffs currently applied and the investment costs turn these options still not attractive so that a final simulation was developed to evaluate the break even value of the tariffs to turn the investments on storage paid in a reasonable horizon.

2015

Evaluation of the Impact of Storage Systems on Grid Electricity Demand in the German Context

Authors
Metz, D; Saraiva, JT;

Publication
2015 12TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
This paper analyzes the impact of storage installations on grid electricity demand. Storage systems allow the decoupling of consumption from electricity generation and therefore have the potential to change the daily demand profile seen by the network in a significant way. This has far reaching consequences for many stakeholders, as changes in the net demand would for example impact electricity prices or change the requirements for peak generation. The developed approach considers the installation of storage devices to increase self-consumption of locally generated electricity in a residential and small commercial end users context as well as its application for electricity arbitrage. Assumptions about their implementation on a system level are described and their impact on overall electricity demand is determined considering the German case.

2015

A Virtual Reservoir Electricity Market Design Applied to the Brazilian System Using an Agent Based Model

Authors
Calabria, FA; Saraiva, JT; Rocha, AP;

Publication
2015 12TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
This paper discusses the current Brazilian electricity market, brings out some dilemmas that should be examined in order to implement a more market-oriented approach, and describes a new market design to overcome these issues. The proposed market design is based on virtual reservoirs and aims at enhancing the flexibility to enable market participants to comply with their contracts, while still ensuring the efficient use of the water and maintaining the current level of the security of supply. In addition, to simulate the behavior of the market participants in this new framework, an Agent-Based Model ABM where agents use reinforcement Q-Learning - is developed and applied to a case study that includes a centralized dispatch as currently exists in Brazil. The results obtained so far show that this new design is suitable to allow hydros managing their commercial contract commitments with extra flexibility.

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