A Graph-Based Power Flow Method for Balanced Distribution Systems
TL;DR: In this paper, a power flow method based on graph theory is presented for three-phase balanced distribution systems, and convergence of the proposed method is proven using the Banach fixed-point theorem.
Abstract: A power flow method based on graph theory is presented for three-phase balanced distribution systems. The graph theory is used to describe the power network and facilitate the derivation of the relationship between bus Currents and the bus Voltage Bias from the feeder bus (the CVB equation). A distinctive feature of the CVB equation is its unified form for both radial and meshed networks. The method requires neither a tricky numbering and layering of nodes nor breaking meshes and loop-analysis, which are both necessary in previous works for meshed networks. The convergence of the proposed method is proven using the Banach fixed-point theorem.
Citations
More filters
TL;DR: Comparisons with classical methods such as Gauss-Seidel, Newton-Raphson, Levenberg-Marquardt, graph-based methods, and linear approximations have been made and implemented in MATLAB software to demonstrate the effectiveness of the proposed approach regarding power flow solutions in radial and mesh distribution networks.
43 citations
TL;DR: In this paper, the efficiency comparison between AC and DC distribution networks that can provide electricity to rural and urban areas from the point of view of grid energy losses and greenhouse gas emissions impact is analyzed via optimal power flow analysis by adding voltage regulation and devices capabilities sources in the mathematical formulation.
Abstract: This research deals with the efficiency comparison between AC and DC distribution networks that can provide electricity to rural and urban areas from the point of view of grid energy losses and greenhouse gas emissions impact Configurations for medium- and low-voltage networks are analyzed via optimal power flow analysis by adding voltage regulation and devices capabilities sources in the mathematical formulation Renewable energy resources such as wind and photovoltaic are considered using typical daily generation curves Batteries are formulated with a linear representation taking into account operative bounds suggested by manufacturers Numerical results in two electrical networks with 024 kV and 1266 kV (with radial and meshed configurations) are performed with constant power loads at all the nodes These simulations confirm that power distribution with DC technology is more efficient regarding energy losses, voltage profiles and greenhouse emissions than its AC counterpart All the numerical results are tested in the General Algebraic Modeling System widely known as GAMS
37 citations
Cites background from "A Graph-Based Power Flow Method for..."
...In the case of the AC technology, it is important to mention that this grid corresponds to a low-voltage distribution network with a single-phase structure, which is the most typical operation case in low-voltage applications [48]....
[...]
TL;DR: The proposed DVSA improves numerical reports found in specialized literature regarding the optimal selection and location of fixed-step capacitor banks with a low computational burden and is carried out in MATLAB software.
Abstract: This paper deals with the problem of the optimal selection of capacitor banks in electrical AC distribution systems for minimizing the costs of energy losses during a year of operation through a discrete version of the vortex search algorithm (DVSA). This algorithm works with a hypersphere with a variable radius defined by an exponential function where a Gaussian distribution is used to generate a set of candidate solutions uniformly distributed around the center of this hypersphere. This center corresponds to the best solution obtained at the iteration t, which is initialized at the center of the solution space at the iterative search beginning. The main advantage of combining the exponential function with the Gaussian distribution is the correct balance between the exploration and exploitation of the solution space, which allows reaching the global optimal solution of the optimization problem with a low standard deviation, i.e., guaranteeing repeatability at each simulation. Two classical distribution networks composed of 33 and 69 nodes were used to validate the proposed DVSA algorithm. They demonstrated that the DVSA improves numerical reports found in specialized literature regarding the optimal selection and location of fixed-step capacitor banks with a low computational burden. All the simulations were carried out in MATLAB software.
31 citations
TL;DR: In this article, the power flow analysis problem for direct-current (DC) grids from a numerical perspective is addressed, and classical and emerging algorithms for power flow solutions in DC networks such as Gauss-Seidel, successive approximations, Newton-Raphson, and Taylor-based methods are reviewed in detail by providing their mathematical derivations and algorithmic implementations.
31 citations
TL;DR: This study analyzed the optimal location and sizing of distributed generators (DGs) in radial distributed networks using a hybrid master-slave metaheuristic technique and demonstrated the efficiency and applicability of the proposed methodology for daily operations with renewable generation.
28 citations
Cites methods from "A Graph-Based Power Flow Method for..."
...Typically used methods include the Newton–Raphson method [2,33,38], classical backward/forward power flow [39,40], and recent approaches such as successive approximations [37,3,9]....
[...]
References
More filters
TL;DR: In this paper, a scheme that utilizes feeder reconfiguration as a planning and/or real-time control tool to restructure the primary feeder for loss reduction is presented.
Abstract: Feeder reconfiguration is defined as altering the topological structures of distribution feeders by changing the open/closed states of the sectionalizing and tie switches. A scheme is presented that utilizes feeder reconfiguration as a planning and/or real-time control tool to restructure the primary feeder for loss reduction. The mathematical foundation of the scheme is given. The solution is illustrated on simple examples. >
1,297 citations
TL;DR: In this article, a power flow method is described for solving weakly meshed distribution and transmission networks, using a multiport compensation technique and basic formations of Kirchoff's laws.
Abstract: A power flow method is described for solving weakly meshed distribution and transmission networks, using a multiport compensation technique and basic formations of Kirchoff's laws. This method has excellent convergence characteristics and is robust. A computer program implementing this scheme was developed and successfully applied to several practical distribution and transmission networks with radial and weakly meshed structures. The method can be applied to the solution of both the three-phase (unbalanced) and single-phase (balanced) representation of the network, however, only the single-phase representation is treated in detail. >
1,108 citations
"A Graph-Based Power Flow Method for..." refers methods in this paper
...have proposed a compensation-based power flow method for solving weakly meshed networks by using the multi-port compensation technique and basic formulations of Kirchhoff’s laws [7]....
[...]
TL;DR: In this paper, a direct approach for unbalanced three-phase distribution load flow solutions is proposed, where two developed matrices, the bus-injection to branch-current matrix and the branchcurrent to busvoltage matrix, and a simple matrix multiplication are used to obtain load flow solution.
Abstract: A direct approach for unbalanced three-phase distribution load flow solutions is proposed in this paper. The special topological characteristics of distribution networks have been fully utilized to make the direct solution possible. Two developed matrices-the bus-injection to branch-current matrix and the branch-current to bus-voltage matrix-and a simple matrix multiplication are used to obtain load flow solutions. Due to the distinctive solution techniques of the proposed method, the time-consuming LU decomposition and forward/backward substitution of the Jacobian matrix or Y admittance matrix required in the traditional load flow methods are no longer necessary. Therefore, the proposed method is robust and time-efficient. Test results demonstrate the validity of the proposed method. The proposed method shows great potential to be used in distribution automation applications.
880 citations
"A Graph-Based Power Flow Method for..." refers background or methods or result in this paper
...However, when solving meshed networks, the method has to apply some preliminary operations, including Kron’s Reduction and modifying the two matrices by loop-analysis [8]....
[...]
...The distinctive feature of our graph-based method is to present a much simpler way than the direct approach in [8]....
[...]
...Method I is the Gauss–Seidel Method, Method II is the Newton–Raphson method, Method III is the direct approach proposed in [8] and Method IV is our Graph-based method....
[...]
...Comparison to the Direct Approach It can be seen that our Algorithm (g1)–(g3) is similar to that in [8]....
[...]
...Recall the CVB equation obtained by the direct approach [8] as: for radial networks,...
[...]
TL;DR: An improved tabu search (ITS) algorithm for loss-minimization reconfiguration in large-scale distribution systems and numerical results well demonstrate the validity and effectiveness of the proposed ITS algorithm.
485 citations
TL;DR: This paper presents allocation of power losses to consumers connected to radial distribution networks before and after network reconfiguration in a deregulated environment and the fuzzy multiobjective approach based on the max-min principle.
Abstract: This paper presents allocation of power losses to consumers connected to radial distribution networks before and after network reconfiguration in a deregulated environment. Loss allocation is made in a quadratic way and it is based on identifying the real and imaginary parts of current in each branch, and losses are allocated to consumers. The network reconfiguration algorithm is based on the fuzzy multiobjective approach and the max-min principle is adopted for the multiobjective optimization in a fuzzy framework. Multiple objectives are considered for real-power loss reduction in which nodes voltage deviation is kept within a range, and an absolute value of branch currents is not allowed to exceed their rated capacities. At the same time, a radial network structure is maintained with all loads energized. The three objectives considered are modeled with fuzzy sets to evaluate their imprecise nature and one can provide his or her anticipated value of each objective. A 69-node example is considered to demonstrate the effectiveness of the proposed method.
450 citations