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Publications

Publications by CPES

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.

2015

Simulation of the operation of hydro plants in an electricity market using Agent-Based Models

Authors
Sousa, JC; Saraiva, JT;

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

Abstract
The optimization and simulation of power systems continues to be an area of concern for electricity companies and researchers worldwide namely considering the development of electricity markets and competition in the generation activity Therefore generation companies are devoting an increasing attention to market issues justifying the development of models to help them preparing bidding strategies to the day-ahead market. In this context, agent-based models have been reported as a complement to optimization and equilibrium models when the problem is too complex to be analyzed by traditional approaches. This paper details an Agent-Based Model for an electricity market considering a detailed modeling for hydro stations and presents some preliminary results taking the Iberian Electricity Market as an example.

2015

A new electricity market design for power systems with large share of hydro: Improving flexibility and ensuring efficiency and security in the Brazilian case

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

Publication
2015 IEEE EINDHOVEN POWERTECH

Abstract
This paper discusses some problems related with the current Brazilian electricity market, brings out some dilemmas that should be examined in order to implement a more market oriented approach, and proposes a new market design to overcome these issues. The proposed market design is based on the concept of energy right accounts as 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 energy resources and maintaining the current security supply level. In addition, in order 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 for the study case. The results show that this new market design is suitable to be applied to hydrothermal systems having a large share of hydros.

2015

Development and implementation of Portuguese smart distribution system

Authors
Gouveia, C; Rua, D; Soares, FJ; Moreira, C; Matos, PG; Pecas Lopes, JAP;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
The consolidation of smart grids is inevitably related with the development and actual implementation of different functionalities envisioned for future electric grids. This paper presents the major implementations of smart grid projects in Portugal, which resulted from a close collaboration between academia and industry. An overview of the entire development process is presented culminating with the real implementation of the developed concepts. The architectures and functional models are presented as the initial step in defining the management and control functionalities for future smart distribution networks. The intermediate step consists in validating the advances introduced by smart grids. Simulation tools are emphasized considering both electrical and communications aspects. Finally, a laboratory infrastructure implemented to be used as a real test bed and a pilot deployed in a large city are presented in the end. The associated learning has provided relevant information for future developments.

2015

Electric vehicles contribution for frequency control with inertial emulation

Authors
Rocha Almeida, PMR; Soares, FJ; Pecas Lopes, JAP;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
This work proposes a novel primary frequency control technique with electric vehicles (EV), the combination of inertial emulation and droop control, for isolated systems. Being EV dispersed along the grids, the impacts of possible delayed actions are assessed. Islanded systems have reduced inertia and so load/generation imbalance situations may lead to large frequency deviations. Therefore, this paper focuses essentially on the EV contribution for primary reserves provision, in order to allow a safe integration of further intermittent Renewable Energy Sources (RES). An avant-garde generation dispatch was adopted for the test system used in this work, fully reliant on RES, mainly conventional hydro units and some wind generation. The studied disturbances include a rapid shortfall on wind power production and a sequence of consecutive events caused by the variability of the wind resource in an ordinary situation.

2015

IMICV fault analysis method with multiple PV grid-connected inverters for distribution systems

Authors
Moura, AP; Lopes, JAP; de Moura, AAF; Sumaili, J; Moreira, CL;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
A novel faults analysis method with multiple PV grid-connected inverters for distribution systems is proposed. The aforesaid proposed method Inverter Matrix Impedance Current Vector (IMICV) employs symmetrical components combined with a matrix denominated of Inverter Matrix Impedance and with a vector denominated Impedance-Current Vector which are formed by inspection. This matrix and this vector are used to solve a linear system of equations where the following post-fault variables are: current in substation, the voltage at the fault point and voltages in the PV grid-connected nodes. A comparison of results obtained using the new method with the results of the professional software ANAFAS validates the method proposed. Computer simulations show that the proposed method for classical shunt faults analysis is efficient, accurate and easy to program.

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