IMPACT OF THE MODELLING DEPTH OF DISTRIBUTION GRIDS ON THE ACCURACY OF AGGREGATED DISTRIBUTION NETWORKS

2021 ◽  
Author(s):  
T. L. Würl ◽  
M. D. Librandi ◽  
R. Witzmann
Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3957
Author(s):  
Andrea Lazzaretto ◽  
Andrea Toffolo

This Special Issue addresses the general problem of a proper match between the demands of energy users and the units for energy conversion and storage, by means of proper design and operation of the overall energy system configuration. The focus is either on systems including single plants or groups of plants, connected or not to one or more energy distribution networks. In both cases, the optimum design and operation involve decisions about thermodynamic processes, about the type, number, design parameters of components/plants, and storage capacities, and about mutual interconnections and the interconnections with the distribution grids. The problem is very wide, can be tackled with different methodologies and may have several, more or less valuable and complicated solutions. The twelve accepted papers certainly represent a good contribution to perceive its difficulty.


Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1580 ◽  
Author(s):  
Raphael Pablo de Souza Barradas ◽  
Gabriel Vianna Soares Rocha ◽  
João Rodrigo Silva Muniz ◽  
Ubiratan Holanda Bezerra ◽  
Marcus Vinícius Alves Nunes ◽  
...  

Direct lightning discharges in overhead distribution networks invariably cause serious insulation damage, frequently leading to the electric system’s partial or total shutdown. Installing lightning arresters can be very effective, and it is commonly used to minimize this problem; however, considering that typically, electric distribution grids exhibit a very large number of electrical nodes, the massive use of lightning arresters may not be economically viable. In this way, this article proposes a methodology for allocating lightning arresters that can significantly reduce the number of lightning arresters installed, but at the same time maintaining an adequate protection level for the distribution grid. The proposed methodology, named Direct Discharge Crossing (DDC), analyzes the network criticality based on two main factors, which are the overvoltage magnitudes and the number of flashovers provoked by lightning discharges, and defines a feeder lightning performance function that is used to indicate the recommended location for lightning arresters’ installation. The simulation studies are accomplished using the IEEE 34 bus distribution grid and ATP software to demonstrate the efficacy of the proposed solution, which is confirmed by the results presented.


2011 ◽  
Vol 48-49 ◽  
pp. 886-890
Author(s):  
Qian Chen ◽  
Xiao Li Li ◽  
Jian Hua Zhang

A growing number of distributed generators have been connected to urban distribution networks in recent years, which brings great challenges to the traditional reliability evaluation of the distribution grids. Island is a new kind of operation mode of the city grid. In consideration of the importance factor of system load, establish the model of island taking the maximum equivalent workload capacity as objective function and heuristic search technology is proposed to solve the problem. According to the island mode of operation, assess the reliability of the network with islands based on equivalent resistance and minimal path, which have certain instructive significance to the improvement of reliability of the modern urban distribution nets.


Author(s):  
Maria Camila Herrera ◽  
Oscar Danilo Montoya ◽  
Alexander Molina-Cabrera ◽  
Luis Fernando Grisales-Noreña ◽  
Diego Armando Giral-Ramirez

<p>This paper addresses the convergence analysis of the triangular-based power flow (PF) method in alternating current radial distribution networks. The PF formulation is made via upper-triangular matrices, which enables finding a general iterative PF formula that does not require admittance matrix calculations. The convergence analysis of this iterative formula is carried out by applying the Banach fixed-point theorem (BFPT), which allows demonstrating that under an adequate voltage profile the triangular-based PF always converges. Numerical validations are made, on the well-known 33 and 69 distribution networks test systems. Gauss-seidel, newton-raphson, and backward/forward PF methods are considered for the sake of comparison. All the simulations are carried out in MATLAB software.</p>


2021 ◽  
Vol 231 ◽  
pp. 01002
Author(s):  
Zahid Ullah ◽  
Nayyar Hussain Mirjat

Integrating decentralised energy sources into the traditional distribution networks can result in technical issues impacting the power quality. Innovative ideas are, therefore, needed to promote the transformation of systems to a smart grid. Distribution System operator (DSO) could make use of the flexibility of emerging technologies as a method to address these power quality issues. This study aims to present an overview of a local flexibility market (LFM) which will allow DSO requirements to be fulfilled through the (VPP) as an energy flexibility provider. The required optimization loads, generators and as well as storage units, are undertaken in the general algebraic modeling simulation (GAMS) environment. The aim of the optimization problem is to provide DSOs the opportunity to increase or curtail the local generations and loads in order to satisfy their requirement. The VPP will then be responsible for handling the relevant requests in real time to ensure the correct operating schedule of a resource is applied. The preliminary results of simulation studies presented in this paper have shown that the local market framework for flexibility could have potential for deferring investments in distribution network capacity, minimizing energy costs and improving the hosting capacity of distribution networks.


Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4500 ◽  
Author(s):  
Giuditta Pisano ◽  
Nayeem Chowdhury ◽  
Massimiliano Coppo ◽  
Nicola Natale ◽  
Giacomo Petretto ◽  
...  

Many planning and operation studies that aim at fully assessing and optimizing the performance of the distribution grids, in response to the current trends, cannot ignore grid limitations. Modelling the distribution system, by including the electrical characteristics of the network (e.g., topology) and end user behaviors, has become complex, but essential, for all conventional and emerging actors/players of power systems (i.e., system and market operators, regulators, new market parties as service providers, aggregators, researchers, etc.). This paper deals with a methodology that, starting from publicly available open data on the energy consumption of a region or wider area, is capable to obtain reasonable load and generation profiles for the network supplied by each primary substation in the region/area. Furthermore, by combining these profiles with territorial and socio-economic information, the proposed methodology is able to model the network in terms of lines, conductors, loads and generators. The results of this procedure are the synthetic networks of the real distribution networks, that do not correspond exactly to the actual networks, but can characterize them in a realistic way. Such models can be used for all the kind of optimization studies that need to check the grid limitations. Results derived from Italian test cases are presented and discussed.


2018 ◽  
Vol 8 (12) ◽  
pp. 2615 ◽  
Author(s):  
Tao Xu ◽  
He Meng ◽  
Jie Zhu ◽  
Wei Wei ◽  
He Zhao ◽  
...  

In the face of the radical revolution of energy systems, there is a gradually held consensus regarding the adoption of distributed renewable energy resources, represented by Photovoltaic (PV) and wind generation. Consequently, the distributed Energy Storage Systems (ESSs) have become increasingly important in the distribution networks, as they provide the arbitrage and ancillary services. Determining the optimal installation site and the capacity of the distributed ESSs will defer the network reinforcements, reduce the investment of ESSs, and improve the reliability, flexibility, and efficiency of distribution grids. In order to investigate the optimal ESS configuration and to solve voltage fluctuations brought by the increased penetration of PV, in this study a two-stage heuristic planning strategy has been proposed, which considers both the economic operation and the lifetime of the distributed ESSs, to determine the optimal sitting and sizing of the ESSs, in the distribution grids. The first stage decides the optimal installation site and the economic scheduling of the ESSs, aiming to minimize the fabricating cost of the distributed ESSs and the network losses. Based on the output of the first stage, the second stage planning is further delivered to achieve the optimal ESS capacity, considering the Life-Cycle Cost (LCC) minimization. Finally, the feasibility and effectiveness of the proposed method is verified on a typical distribution case study network.


2021 ◽  
Vol 11 (5) ◽  
pp. 1972
Author(s):  
Alejandro Garces ◽  
Walter Gil-González ◽  
Oscar Danilo Montoya ◽  
Harold R. Chamorro ◽  
Lazaro Alvarado-Barrios

Phase balancing is a classical optimization problem in power distribution grids that involve phase swapping of the loads and generators to reduce power loss. The problem is a non-linear integer and, hence, it is usually solved using heuristic algorithms. This paper proposes a mathematical reformulation that transforms the phase-balancing problem in low-voltage distribution networks into a mixed-integer convex quadratic optimization model. To consider both conventional secondary feeders and microgrids, renewable energies and their subsequent stochastic nature are included in the model. The power flow equations are linearized, and the combinatorial part is represented using a Birkhoff polytope B3 that allows the selection of phase swapping in each node. The numerical experiments on the CIGRE low-voltage test system demonstrate the use of the proposed formulation.


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