scholarly journals Efficient Integration of Three-Phase Step Voltage Regulators in the Z-Bus Power Flow Method

2021 ◽  
Author(s):  
Evangelos Pompodakis
Keyword(s):  
Power Flow ◽  
Computation Time ◽  
Voltage Regulators ◽  
Voltage Regulator ◽  
Phase Step ◽  
Flow Method ◽  
Step Voltage ◽  
Three Phase ◽  
Efficient Integration ◽  
Bus Network

This letter presents a comprehensive Step Voltage Regulator (SVR) model suitable for the three-phase Z<sub>BUS</sub> power flow. The model can be applied in all SVR configurations such as open delta, close delta, wye. Its advantage is that the tap variations are simulated outside the Y<sub>BUS</sub> matrix, without compromising the convergence of the power flow. Therefore, a refactorization of the Y<sub>BUS</sub> matrix is not required after every tap change reducing significantly the computation time of the power flow. The proposed SVR model is validated in a 4-Bus network, while its performance is tested in the IEEE 8500-Node test feeder.

scholarly journals Efficient Integration of Three-Phase Step Voltage Regulators in the Z-Bus Power Flow Method

2021 ◽  
Author(s):  
Evangelos Pompodakis
Keyword(s):  
Power Flow ◽  
Computation Time ◽  
Voltage Regulators ◽  
Voltage Regulator ◽  
Phase Step ◽  
Flow Method ◽  
Step Voltage ◽  
Three Phase ◽  
Efficient Integration ◽  
Bus Network

This letter presents a comprehensive Step Voltage Regulator (SVR) model suitable for the three-phase Z<sub>BUS</sub> power flow. The model can be applied in all SVR configurations such as open delta, close delta, wye. Its advantage is that the tap variations are simulated outside the Y<sub>BUS</sub> matrix, without compromising the convergence of the power flow. Therefore, a refactorization of the Y<sub>BUS</sub> matrix is not required after every tap change reducing significantly the computation time of the power flow. The proposed SVR model is validated in a 4-Bus network, while its performance is tested in the IEEE 8500-Node test feeder.

scholarly journals A Comprehensive Three-Phase Step Voltage Regulator Model with Efficient Implementation in the Z-Bus Power Flow

2021 ◽  
Author(s):  
Evangelos Pompodakis ◽  
Georgios C. Kryonidis ◽  
Minas Alexiadis
Keyword(s):  
Power Flow ◽  
Equivalent Circuit Model ◽  
Computation Time ◽  
Voltage Regulators ◽  
Equivalent Model ◽  
Voltage Regulator ◽  
Phase Step ◽  
Step Voltage ◽  
Proposed Model ◽  
Three Phase

<p>This paper presents a comprehensive three-bus equivalent circuit model of three-phase step voltage regulators. The proposed model can be efficiently integrated in the Z-bus power flow method and can accurately simulate any configuration of step voltage regulators. In contrast to the conventional step voltage regulator models that include the tap variables inside the Y<sub>BUS</sub> matrix of the network, the proposed model simulates them in the form of current sources, outside the Y<sub>BUS</sub> matrix. As a result, the re-factorization of the Y<sub>BUS</sub> matrix is avoided after every tap change reducing significantly the computational burden of the power flow. Furthermore, possible convergence issues caused by the low impedance of step voltage regulators are addressed by introducing fictitious impedances, without, however, affecting the accuracy of the model. The results of the proposed step voltage regulator model are compared against well-known commercial softwares such as Simulink and OpenDSS using the IEEE 4-Bus and an 8-Bus network. According to the simulations, the proposed model outputs almost identical results with Simulink and OpenDSS confirming its high accuracy. Furthermore, the proposed 3-bus equivalent model is compared against a recently published conventional step voltage regulator model in the IEEE 8500-Node test feeder. Simulation results indicate that the proposed step voltage regulator model produces as accurate results as the conventional one, while its computation time is significantly lower. More specifically, in the large IEEE 8500-node network consisting of four SVRs, the proposed model can reduce the computation time of power flow around one minute for every tap variation. Therefore, the proposed step voltage regulator model can constitute an efficient simulation tool in applications where subsequent tap variations are required. </p>

scholarly journals Three-Phase Step Voltage Regulator Model for the Z-Bus Power Flow

2020 ◽  
Author(s):  
Evangelos Pompodakis
Keyword(s):  
Power Flow ◽  
Computation Time ◽  
Voltage Regulator ◽  
Phase Step ◽  
Step Voltage ◽  
Three Phase ◽  
Bus Network

<b>This letter presents a comprehensive Step Voltage Regulator (SVR) model suitable for the three-phase Z<sub>BUS</sub> power flow. The model can be applied in all SVR configurations such as open delta, close delta, wye. Its advantage is that the tap variations are simulated outside the Y<sub>BUS</sub> matrix, without compromising the convergence of the power flow. Therefore, a refactorization of the Y<sub>BUS</sub> matrix is not required after every tap change reducing significantly the computation time of the power flow. The proposed SVR model is validated in a 4-Bus network, while its performance is tested in the IEEE 8500-Node test feeder. </b>

scholarly journals Optimal Selection of Conductors in Three-Phase Distribution Networks Using a Discrete Version of the Vortex Search Algorithm

Computation ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 80
Author(s):  
John Fernando Martínez-Gil ◽  
Nicolas Alejandro Moyano-García ◽  
Oscar Danilo Montoya ◽  
Jorge Alexander Alarcon-Villamil
Keyword(s):  
Objective Function ◽  
Power Flow ◽  
Phase Distribution ◽  
Search Algorithm ◽  
Distribution Networks ◽  
Discrete Version ◽  
Optimal Selection ◽  
Flow Method ◽  
Three Phase ◽  
Selection Of

In this study, a new methodology is proposed to perform optimal selection of conductors in three-phase distribution networks through a discrete version of the metaheuristic method of vortex search. To represent the problem, a single-objective mathematical model with a mixed-integer nonlinear programming (MINLP) structure is used. As an objective function, minimization of the investment costs in conductors together with the technical losses of the network for a study period of one year is considered. Additionally, the model will be implemented in balanced and unbalanced test systems and with variations in the connection of their loads, i.e., Δ− and Y−connections. To evaluate the costs of the energy losses, a classical backward/forward three-phase power-flow method is implemented. Two test systems used in the specialized literature were employed, which comprise 8 and 27 nodes with radial structures in medium voltage levels. All computational implementations were developed in the MATLAB programming environment, and all results were evaluated in DigSILENT software to verify the effectiveness and the proposed three-phase unbalanced power-flow method. Comparative analyses with classical and Chu & Beasley genetic algorithms, tabu search algorithm, and exact MINLP approaches demonstrate the efficiency of the proposed optimization approach regarding the final value of the objective function.

scholarly journals Accurate and Efficient Derivative-Free Three-Phase Power Flow Method for Unbalanced Distribution Networks

Computation ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 61
Author(s):  
Oscar Danilo Montoya ◽  
Juan S. Giraldo ◽  
Luis Fernando Grisales-Noreña ◽  
Harold R. Chamorro ◽  
Lazaro Alvarado-Barrios
Keyword(s):  
Power Flow ◽  
Triangular Matrix ◽  
Distribution Networks ◽  
Flow Method ◽  
Processing Times ◽  
Three Phase ◽  
Derivative Free ◽  
Upper Triangular Matrix ◽  
Power Flow Problem ◽  
Power Flow Method

The power flow problem in three-phase unbalanced distribution networks is addressed in this research using a derivative-free numerical method based on the upper-triangular matrix. The upper-triangular matrix is obtained from the topological connection among nodes of the network (i.e., through a graph-based method). The main advantage of the proposed three-phase power flow method is the possibility of working with single-, two-, and three-phase loads, including Δ- and Y-connections. The Banach fixed-point theorem for loads with Y-connection helps ensure the convergence of the upper-triangular power flow method based an impedance-like equivalent matrix. Numerical results in three-phase systems with 8, 25, and 37 nodes demonstrate the effectiveness and computational efficiency of the proposed three-phase power flow formulation compared to the classical three-phase backward/forward method and the implementation of the power flow problem in the DigSILENT software. Comparisons with the backward/forward method demonstrate that the proposed approach is 47.01%, 47.98%, and 36.96% faster in terms of processing times by employing the same number of iterations as when evaluated in the 8-, 25-, and 37-bus systems, respectively. An application of the Chu-Beasley genetic algorithm using a leader–follower optimization approach is applied to the phase-balancing problem utilizing the proposed power flow in the follower stage. Numerical results present optimal solutions with processing times lower than 5 s, which confirms its applicability in large-scale optimization problems employing embedding master–slave optimization structures.

Sign in / Sign up

Export Citation Format

Share Document