Determination of local voltage control strategy of distributed generators in active distribution networks based on kriging metamodel

The increasing penetration of uncontrollable distributed generators (NDGs) exacerbates the risk of voltage violations in active distribution networks (ADNs). It is difficult for a centralized control strategy to meet the requirements of fast voltage and reactive power control because of the heavy computational and communication burdens. Local voltage control based on real-time measurements can respond quickly to the frequent fluctuations of distributed generators (DGs). In this paper, a local voltage control strategy of DGs with reactive power optimization based on a kriging metamodel is proposed. First, to build the metamodel for local voltage control, the steps for determining the input variables are presented in detail, and the effects of different variables on the accuracy of the metamodel are analyzed. Then, taking minimum network losses and voltage deviations as the objective function, we construct the metamodel for local voltage control based on kriging methods. Finally, operation strategies for DGs are developed by calculating the optimally weighted vector based on real-time measurements, and the operation strategies for DGs will be added into the original sample set to improve the accuracy of the metamodel. The proposed local voltage control strategy based on only the local measurements can quickly respond to the frequent DG fluctuations, reduce the communication burden for large networks and improve the adaptability of local voltage control in ADNs. Case studies under different scenarios on the IEEE 33-node system and the IEEE 123-node system are conducted to verify the effectiveness of the proposed method, and the results show that the proposed method can effectively solve the problems of voltage deviation and voltage fluctuation caused by the high penetration of DGs

MULTI-OBJECTIVE OPTIMAL CAPACITY AND PLACEMENT OF DISTRIBUTED GENERATORS IN THE POWER SYSTEM NETWORKS USING ATOM SEARCH OPTIMIZATION METHOD

Nowadays, renewable energy sources become a significant source of energy in the new millennium. The continuous penetration of dispersed resources of the reactive power into power systems is predicted to introduce new challenges. Power loss mitigation and voltage profile development are the major investigation challenges that recently attracted the attention of researchers in the field of power systems. Distributed generation (DG) is widely preferred because it is a highly effective solution that strengthens the performance of power system networks. This multiobjective function study aims to minimise power losses in the feeders, sustain voltage levels and reduce the application cost of DGs by adapting the atom search optimisation simulated on MATLAB software. Two different IEEE power test systems, namely, a 33 bus radial distribution system (RDS) and a 14-bus power system that hosts 1, 2 and 3 DGs in both systems, are demonstrated in this research. Correspondingly, backward–forward sweep and Newton–Raphson power flow methods are used for each system. The proposed technique is compared with the genetic algorithm particle swarm optimisation (GA-PSO) method. Results depict the effectiveness of the proposed method in minimising system power losses and in regulating the voltage profile where the power loss reduction is 25.38% in the 33 bus RDS using 2 DGs. By contrast, the power loss reduction percentages in the 14 bus system are 0.316% and 0.169% in systems with 1 and 2 DGs, respectively. The voltage profile has been enhanced compared with those in the original case and the results obtained from the GA-PSO method

Estimativa em tempo real de micro e minigeração em redes de distribuição

Orientadora: Prof(a). Dr(a). Elizete Maria LourençoCoorientador: Prof. Dr. Odilon Luis TortelliDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Elétrica. Defesa : Curitiba, 28/06/2021Inclui referências: p. 93-99Resumo: Os últimos anos serão lembrados como a época em que mudanças profundas no sistema elétrico de potência começaram a ser implementadas. Estas mudanças, que visam atender às necessidades energéticas que acompanham o aumento da demanda e o desenvolvimento tecnológico na área, afetam as instalações físicas dos sistemas e a sua operação. Consequentemente a forma de planejar, operar e manter o sistema elétrico de potência, necessita ser revisto. Estas mudanças são impulsionadas pelo novo modelo de suprimento de energia, feito a partir de então, com a contribuição da micro e minigeração, fontes distribuídas instaladas próximos as cargas. Este novo formato é apontado como a melhor resposta as necessidades atuais, mas traz, simultaneamente, desafios que devem ser devidamente enfrentados. Um destes desafios diz respeito a intermitência no suprimento de energia por parte das fontes de micro e minigeração, impactando o sistema com uma variabilidade inexistente até então. Esta dissertação examina o processo de transformação do sistema elétrico e propõe uma ferramenta capaz de fornecer ao operador do sistema, em tempo real, informações relativas ao funcionamento das fontes distribuídas, à saber: localização e quantidade de energia fornecida ao sistema. Para fornecer esta informação a normalização complexa por unidade é utilizada em substituição à normalização convencional, permitindo a utilização de formulações clássicas, com robustez e eficiência destacadas para sistemas de transmissão, no processo de estimação de estados de sistemas de distribuição. Na metodologia proposta, o estado do sistema é obtido por meio de métodos desacoplados, mais eficientes para utilização em sistemas de grande porte, como é o caso dos sistemas de distribuição que podem alcançar milhares de barras. A partir do estado estimado, as equações tradicionais de fluxo de potência são requeridas para obtenção das informações necessárias para a correta estimativa das fontes de micro e minigeração. Algoritmos específicos e pacotes computacionais desenvolvidos no grupo de pesquisa onde esta pesquisa está inserida estão vinculados a esta proposta para fornecer uma ferramenta de suporte ao operador do sistema, em tempo real, com elevada precisão. A eficiência da abordagem proposta é avaliada por meio de um sistema de distribuição radial real, localizado na região metropolitana de Caracas, contendo 141 barras. Os resultados obtidos demonstraram a viabilidade e a eficiência da ferramenta proposta para estimação da atividade das fontes de micro e minigeração com elevado grau de precisão.Abstract: The last few years will be remembered as the time when profound changes in the electrical power system started to be implemented. These changes, which aim to meet the energy needs that accompany the increase in demand and technological development in the area, affect the physical installations of the systems and their operation. Consequently, the way to plan, operate and maintain the electric power system needs to be revised. These changes are driven by the new model of energy supply, made since then, with the contribution of micro and mini generation, distributed sources installed close to the loads. This new format is identified as the best answer to current needs, but, at the same time, it brings challenges that must be properly addressed. One of these challenges involves the intermittency of the micro and mini generation sources, which impacts the system with variability that did not exist until then. This dissertation examines the transformation process faced by the electrical system and proposes a tool capable of providing to the system operator, in real-time, information regarding the functioning of the distributed sources, namely: location and the amount of energy supplied to the system. To provide this information, conventional per unit normalization is replaced by complex per unit normalization, allowing that transmission system classic state estimation to be applied to distribution networks. Robustness and efficiency highlighted into transmission systems are then transferred to the state estimation process of distribution systems as well. In the proposed methodology, the state of the system is obtained using decoupled methods, more efficient for use in large systems, as is the case of distribution systems that can reach thousands of buses. From the estimated state, the traditional power flow equations are required to obtain the necessary information and to correctly estimate the micro and mini generation sources. Specific algorithms and computational packages developed in the research group where this research is inserted are linked in this proposal to provide a tool to give support to the system operator, in real-time and with high precision. The efficiency of the proposed approach is demonstrated through a real radial distribution test system, located in the metropolitan region of Caracas, containing 141 buses. The results obtained demonstrated the feasibility and efficiency of the proposed tool for estimating the activity of micro and mini generation sources with a high degree of accuracy