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About

About

João A. Peças Lopes (PhD) is Full Professor (Professor Catedrático) at the Faculty of Engineering of Porto University, where he teaches in the graduation and post-graduation areas.

Was for 7 years Director of the Sustainable Energy Systems PhD program at FEUP and Director of Advanced course on Sustainable Energy Systems also at FEUP.
He is Director/Member of the Board of INESC TEC.

He is Vice-Presidente of the board of the Portuguese Association for Electric Vehicles.

Prof. Peças Lopes was responsible by INESC Porto activities in several EU financed research projects, namely the project - MICROGRIDS - Large Scale Integration of Micro Generation to Low Voltage Grids  and MORE_MICROGRIDS -  Advanced Architectures and Control Concepts for More Microgrids and MERGE - Mobile Energy Resources for Grids of Electricity.

He supervised several consulting projects related with the impact analysis of the connection of wind parks in the electrical grids of Madeira, Azores,  Sal, S. Vicente and S. Tiago, in the Republic of Cabo Verde. He was the responsible for several consultancy projects related with the electrical grid impact resulting from the connection of large wind parks in Portugal.

He was also responsible for the definition of technical rules for the integration of wind power in Brazil. He coordinated also consultancy studies for the Hungarian Regulator regarding the evaluation of the integration of wind power in Hungary. He coordinates the participation of INESC Porto in the InovGrid project.

He was also the Chair of the Selection Committee of the public tender that decided about the integration of 1800 MW of wind generation in Portugal, launched by the Portuguese government in 2005.

He was member of the Executive board of the EES/UETP consortium and Chair of its course program committee.

He has served as research project evaluator for the European Commission and for governmental science organizations in Portugal, France, Italy, Greece, Finland, Danemark and Ireland.

He was for more than 4 years one of the coordinators of INESC Porto Power System Unit.

He is co-editor of the (SEGAN) Sustainable Energy Grids and Networks journal.

His main domains of research are presently related with large scale integration of renewable power sources in power systems (namely wind generation), power system dynamics, microgrids, smartmetering and integration of electric vehicles in electrical grids.

In 2012 he received the CIGRE Technical Committee Award in recogmition of his outstanding contribution to the work of the Study Committee C6 – Distribution Systems and Dispersed Generation.

Prof. Peças Lopes is an IEEE Fellow
He is member of the Power Systems Dynamic Performance Committee of the IEEE PES.

Details

Details

  • Name

    João Peças Lopes
  • Cluster

    Power and Energy
  • Role

    Associate Director
  • Since

    01st March 1989
094
Publications

2023

Improving Dynamic Security in Islanded Power Systems: Quantification of Minimum Synchronous Inertia Considering Fault-Induced Frequency Deviations

Authors
Gouveia, J; Moreira, L; Peças Lopes, A;

Publication
Electricity

Abstract
In isolated power systems with very high instantaneous shares of renewables, additional inertia should be used as a complementary resource to battery energy storage systems (BESSs) for improving frequency stability, which can be provided by synchronous condensers (SCs) integrated into the system. Therefore, this paper presents a methodology to infer the system dynamic security, with respect to key frequency indicators, following critical disturbances. Of particular interest is the evidence that multiple short-circuit locations should be considered as reference disturbances regarding the frequency stability in isolated power grids with high shares of renewables. Thus, an artificial neural network (ANN) structure was developed, aiming to predict the network frequency nadir and Rate of Change of Frequency (RoCoF), considering a certain operating scenario and disturbances. For the operating conditions where the system frequency indicators are violated, a methodology is proposed based on a gradient descent technique, which quantifies the minimum amount of additional synchronous inertia (SCs which need to be dispatch) that moves the system towards its dynamic security region, exploiting the trained ANN, and computing the sensitivity of its outputs with respect to the input defining the SC inertia.

2021

An improved version of the Continuous Newton's method for efficiently solving the Power-Flow in Ill-conditioned systems

Authors
Tostado Veliz, M; Matos, MA; Lopes, JAP; Jurado, F;

Publication
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS

Abstract
This paper tackles the efficient Power-Flow solution of ill-conditioned cases. In that sense, those methods based on the Continuous Newton's philosophy look very promising, however, these methodologies still present some issues mainly related with the computational efficiency or the robustness properties. In order to overcome these drawbacks, we suggest several modifications about the standard structure of the Continuous Newton's method. Thus, the standard Continuous Newton's paradigm is firstly modified with a frozen Jacobian scheme for reducing its computational burden; secondly, it is extended for being used with High-order Newton-like method for achieving higher convergence rate and, finally, a regularization scheme is introduced for improving its robustness features. On the basis of the suggested improvements, a Power-Flow solution paradigm is developed. As example, a novel Power-Flow solver based on the introduced solution framework and the 4th order Runge-Kutta formula is developed. The novel technique is validated in several realistic large-scale ill-conditioned systems. Results show that the suggested modifications allow to overcome the drawbacks presented by those methodologies based on the Continuous Newton's method. On the light of the results obtained it can be also claimed, that the developed solution paradigm constitutes a promising framework for developing robust and efficient Power-Flow solution techniques.

2021

Influence of Load Dynamics on Converter-Dominated Isolated Power Systems

Authors
Gouveia, J; Moreira, CL; Lopes, JAP;

Publication
APPLIED SCIENCES-BASEL

Abstract
The operation of isolated power systems with 100% converter-based generation requires the integration of battery energy storage systems (BESS) using grid-forming-type power converters. Under these operating conditions, load dynamics influences the network frequency and voltage following large voltage disturbances. In this sense, the inclusion of induction motor (IM) load models is required to be properly considered in BESS power converter sizing. Thus, this paper presents an extensive sensitivity analysis, demonstrating how load modeling affects the BESS power converter capacity when adopting conventional control strategies while aiming to assure the successful recovery of all IM loads following a network fault. Furthermore, this work highlights that generators with converter interfaces can actively contribute to mitigate the negative impacts resulting from IM loads following a network fault. Thereby, two distinct control strategies are proposed to be integrated in the power electronic interfaces of the available converter-based generators: one to be adopted in grid-following converters and another one suitable for grid-forming converters. The proposed control strategies provide an important contribution to consolidating insular grid codes, aiming to achieve operational scenarios accommodating 100% penetration of converter-based generation with a significative percentage of the IM load composition without resorting to a significative increase in BESS power converter sizing.

2021

Rule-based adaptive control strategy for grid-forming inverters in islanded power systems for improving frequency stability

Authors
Gouveia, J; Moreira, CL; Lopes, JAP;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Operating isolated power systems with increasing shares of renewable energy sources requires the integration of battery energy storage systems in order to assure enhanced frequency regulation capabilities. The control mode of power converters interfacing battery energy storage systems to the grid can be based on grid-forming type structures given its superior performance with respect to the mitigation of network frequency disturbances. Nevertheless, in case of network faults, the interactions between existing synchronous units and the grid-forming type converters may adversely affect the global system behavior. Therefore, this paper addresses the study-case of a MW-scale isolated power system with large shares of converter-interfaced renewable generation, operating with both synchronous machines and a grid-forming type power converter. An optimal grid-forming control parameter tuning procedure considering different disturbances is presented, aiming to reduce the associated battery energy storage system power regulating effort following the disturbances. Moreover, it is proposed and discussed the need of a novel rule-based adaptive control solution to switch between different sets of control parameters used in grid-forming type converters depending on the network status following a fault-type disturbance. Extensive numerical simulations performed over different operating scenarios illustrate the performance of the proposed solution.

2021

Hydrogen and the transition from gas networks to a new energy carrier paradigm: Portuguese challenges of the national roadmap

Authors
Santos, BH; Peças Lopes, JA;

Publication
U.Porto Journal of Engineering

Abstract
Portugal has developed a national roadmap for hydrogen deployment as a key element of the Portuguese energy transition towards carbon neutrality, with a major contribution towards the electrification of society, generating synergies between the electric and gas systems. Considering the government goals for hydrogen injection within natural gas infrastructures for 2025 and 2030, as long as the indicative trajectories for 2040 and 2050, the authors used the natural gas forecast of the security of supply official report in order to obtain the hydrogen demand and power plant capacity, evaluating the system effort to meet public policy goals. Several alternative scenarios were developed for sensitive analysis, in order to assess the different strategies of hydrogen deployment, considering production from an electrolyzer. Regarding the current Portuguese situation and every scenario outcome, the authors stated that major efforts must be undertaken in order to develop full-scale hydrogen projects in order to meet the national goals.

Supervised
thesis

2022

Contributions for improving the stability of autonomous power systems with low synchronous inertia

Author
José Miguel Rodrigues Gouveia

Institution
UP-FEUP

2022

Modeling energy sector integration using green hydrogen to define public policies and new regulatory support schemes to accelerate energy transition

Author
Bruno Henrique Martins Santos

Institution
UP-FEUP

2022

Advanced Control Functionalities for Smart-Transformers Integrating Hybrid MicroGrids

Author
Justino Miguel Ferreira Rodrigues

Institution
UP-FEUP

2022

Network-Secure Participation of Aggregators of Multi-Energy Systems in Multi-Energy Markets

Author
António Manuel Freitas Coelho

Institution
UP-FEUP

2022

Islanding Operation and Black Start Strategies for Multi-Microgrids using the Smart Transformer

Author
Mário Jorge Teixeira Couto

Institution
UP-FEUP