scholarly journals A Phase Generation Shifting Algorithm for Prosumer Surplus Management in Microgrids using Inverter Automated Control

Author(s):  
Ovidiu Ivanov ◽  
Bogdan Constantin Neagu ◽  
Mihai Gavrilaș ◽  
Gheorghe Grigoraș

Four-wire low voltage microgrids supply one-phase consumers with continuously changing electricity demand. For addressing climate change concerns, governments implemented incentive schemes for residential consumers, encouraging the installation of home PV panels for covering self-consumption needs. In the absence of sufficient storage capacities, the surplus is sold back by these entities, called prosumers, to the grid operator or in local markets, to other consumers. While these initiatives encourage the proliferation of green energy resources, and ample research is dedicated to local market designs for prosumer-consumer trading, the main concern of distribution network operators is the influence of power flows generated by prosumer surplus injection on the operating states of microgrids. The change in power flow amount and direction can greatly influence the economic and technical operating conditions of radial grids. This paper proposes a metaheuristic algorithm for prosumer surplus management that optimizes the power surplus injections using the automated control of three-phase inverters, with the aim of improving the active power losses and balancing the phase voltage profiles. A case study is performed on two real distribution networks with distinct layouts and load profiles and the algorithm shows its efficiency in both scenarios.

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2740
Author(s):  
Ovidiu Ivanov ◽  
Bogdan-Constantin Neagu ◽  
Mihai Gavrilas ◽  
Gheorghe Grigoras

Four-wire low-voltage microgrids supply one-phase consumers with electricity, responding to a continuously changing demand. For addressing climate change concerns, national governments have implemented incentive schemes for residential consumers, encouraging the installation of home PV panels for covering self-consumption needs. In the absence of adequate storage capacities, the surplus is sold back by these entities, called prosumers, to the grid operator or, in local markets, to other consumers. While these initiatives encourage the proliferation of green energy resources, and ample research is dedicated to local market designs for prosumer–consumer trading, the main concern of distribution network operators is the influence of power flows generated by prosumers’ surplus injection on the operating states of microgrids. The change in power flow amount and direction can greatly influence the economic and technical operating conditions of radial grids. This paper proposes a metaheuristic algorithm for prosumer surplus management that optimizes the power surplus injections using the automated control of three-phase inverters, with the aim of reducing the active power losses over a typical day of operation. A case study was performed on two real distribution networks with distinct layouts and load profiles, and the algorithm resulted efficient in both scenarios. By optimally distributing the prosumer generation surplus on the three phases of the network, significant loss reductions were obtained, with the best results when the generated power was injected in an unbalanced, three-phase flow.


Author(s):  
Ovidiu Ivanov ◽  
Bogdan-Constantin Neagu ◽  
Gheorghe Grigoraș ◽  
Florina Scarlatache ◽  
Mihai Gavrilaș

The global climate change mitigation efforts have increased the efforts of national government to incentivize local households in adopting individual renewable energy as a mean to help reduce the usage of electricity generated using fossil fuels and to gain independence from the grid. Since the majority of residential generation is made by PV panels that generate electricity at off-peak hours, the optimal management of such installations often considers local storage that can defer the use of locally generated electricity at later times. On the other hand, the presence of distributed generation can affect negatively the operating conditions of low-voltage distribution networks. The energy stored in batteries located in optimal places in the network can be used by the utility to improve the operation of the network. This paper proposes a metaheuristic approach based on a Genetic Algorithm that considers three different scenarios of using energy storage for reducing the losses in the network. Prosumer and network operator priorities can be considered in different scenarios inside the same algorithm, to provide a comparative study of different priorities in storage placement. A case study performed on a real distribution network provides insightful results.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1866
Author(s):  
Zahid Javid ◽  
Ulas Karaagac ◽  
Ilhan Kocar ◽  
Ka Wing Chan

There is an increasing interest in low voltage direct current (LVDC) distribution grids due to advancements in power electronics enabling efficient and economical electrical networks in the DC paradigm. Power flow equations in LVDC grids are non-linear and non-convex due to the presence of constant power nodes. Depending on the implementation, power flow equations may lead to more than one solution and unrealistic solutions; therefore, the uniqueness of the solution should not be taken for granted. This paper proposes a new power flow solver based on a graph theory for LVDC grids having radial or meshed configurations. The solver provides a unique solution. Two test feeders composed of 33 nodes and 69 nodes are considered to validate the effectiveness of the proposed method. The proposed method is compared with a fixed-point methodology called direct load flow (DLF) having a mathematical formulation equivalent to a backward forward sweep (BFS) class of solvers in the case of radial distribution networks but that can handle meshed networks more easily thanks to the use of connectivity matrices. In addition, the convergence and uniqueness of the solution is demonstrated using a Banach fixed-point theorem. The performance of the proposed method is tested for different loading conditions. The results show that the proposed method is robust and has fast convergence characteristics even with high loading conditions. All simulations are carried out in MATLAB 2020b software.


Energies ◽  
2018 ◽  
Vol 11 (5) ◽  
pp. 1156 ◽  
Author(s):  
Nikoleta Andreadou ◽  
Evangelos Kotsakis ◽  
Marcelo Masera

The modernization of the distribution grid requires a huge amount of data to be transmitted and handled by the network. The deployment of Advanced Metering Infrastructure systems results in an increased traffic generated by smart meters. In this work, we examine the smart meter traffic that needs to be accommodated by a real distribution system. Parameters such as the message size and the message transmission frequency are examined and their effect on traffic is showed. Limitations of the system are presented, such as the buffer capacity needs and the maximum message size that can be communicated. For this scope, we have used the parameters of a real distribution network, based on a survey at which the European Distribution System Operators (DSOs) have participated. For the smart meter traffic, we have used two popular specifications, namely the G3-PLC–“G3 Power Line communication” and PRIME–acronym for “PoweRline Intelligent Metering Evolution”, to simulate the characteristics of a system that is widely used in practice. The results can be an insight for further development of the Information and Communication Technology (ICT) systems that control and monitor the Low Voltage (LV) distribution grid. The paper presents an analysis towards identifying the needs of distribution networks with respect to telecommunication data as well as the main parameters that can affect the Inverse Fast Fourier Transform (IFFT) system performance. Identifying such parameters is consequently beneficial to designing more efficient ICT systems for Advanced Metering Infrastructure.


2021 ◽  
Author(s):  
Evangelos Pompodakis ◽  
Andreas I. Chrysochos ◽  
Arif Ahmed ◽  
Minas C. Alexiadis

<p>This manuscript proposes a time-series temperature-dependent power flow method for unbalanced distribution networks consisting of underground cables. A thermal circuit model for unbalanced three-phase multi-core cables is developed to estimate the conductor temperature and resistance of Medium and Low Voltage distribution networks. More specifically, a novel approach is proposed to model and estimate the parameters of the three-phase thermal circuit of 3/4-core cables, using the results of Finite Element Method and Particle Swarm Optimization. The proposed approach is generic and can be accurately applied to any kind of 3- or 4-core cables buried in homogeneous or non-homogeneous soil. Furthermore, it is applicable in cases where one or more adjacent cables exist. Using the proposed approach, the conductor temperature of each phase can be individually and precisely calculated even in networks with highly unbalanced loads. The proposed approach is expected to be an important tool for simulating the steady state of unbalanced distribution networks and estimating the conductor temperatures. The proposed thermal circuit is validated using two 4-core LV and one 3-core MV cables buried in different depths in homogeneous or non-homogeneous soil. Time-series power flow for a whole year is performed in a 25-bus unbalanced LV network consisting of multicore underground cables.</p>


Author(s):  
Chinweike Innocent Amesi ◽  
Tekena Kashmony Bala ◽  
Anthony O. Ibe

This paper examined the power flow status of the Port Harcourt Town (Zone 4) distribution networks to improve the performance. The network consists of 18 injection substations fed from 4 different sizes of transformers with a total power rating of 165 MVA, 132/33kV at the Port Harcourt Town sub-transmission substation. Gauss-seidel power flow algorithm was used to analyse the network in Electrical Transient Analyzer Program software (ETAP 12.6) to determine the various bus operating voltages, power flow, and over or under-loaded Transformers’ units. From the base-case simulation results obtained, it shows that these injection distribution transformers (PH Town 106.3%, RSU 90.5%, Marine Base 86.5%, UTC 87.9%, Nzimiro 89.5%, and Borokiri 88.7%) were overloaded on the network and the operating voltages observed for (PH Town 95.1%, RSU 83.0%, Marine Base 83.4%, UTC 82.8%, Nzimiro 85.2%, and Borokiri 82.1%) indicates low voltage profile. However, using network reconfiguration technique as proposed in this paper; there was reduction in the percentage loading of the said Transformers as it was upgraded to affect positively on its lifespan with (PH Town 44.1%, RSU 65.3%, Marine Base 60.7%, UTC 47.3%, Nzimiro 61.3%, and Borokiri 52.0%) loading,  and the bus voltage profiles was improved for (PH Town 100%, RSU 98.4%, Marine Base 98.8%, UTC 98.2%, Nzimiro 98.6%, and Borokiri 99.1%) with additional facilities. It is recommended that the power infrastructure facilities in Port Harcourt Town distribution network be immediately upgraded to reduce losses and improve the electricity supply to consumers. Also, in regard to these analyses, the sub-transmission substation requires 240 MW of power for effective power delivery.


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