scholarly journals Hybrid AC/DC Microgrid Planning with Optimal Placement of DC Feeders

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1751 ◽  
Author(s):  
Xiong Wu ◽  
Zhao Wang ◽  
Tao Ding ◽  
Zhiyi Li
Keyword(s):  
Power Distribution ◽  
Power Flow ◽  
Distribution Systems ◽  
Optimal Number ◽  
Security Requirements ◽  
Optimal Placement ◽  
Planning Model ◽  
Dc Microgrid ◽  
Dc Distribution ◽  
Proposed Model

With the significant increase in DC loads (such as data and telecommunication centers) at the power distribution level, an additional set of power electronic converters are required to connect these DC loads to the AC-dominant power network. Notably, hybrid AC/DC microgrids (MGs) serve as promising solutions to satisfying both the AC and DC loads with a reduced number of installed converters. Since DC loads may be randomly distributed in the MG, how to place DC feeders to simultaneously fulfill the economic and security requirements of MG operations remains a challenging problem. To address this issue, this paper proposes a hybrid AC/DC MG planning model to determine the optimal placement of DC feeders with the objective of minimizing the total cost of the investment of distributed energy resources (DERs), converters, and AC/DC distribution lines, as well as the operation of DERs. In particular, the power flow of the hybrid AC/DC MG is derived in a unified manner and then incorporated in the planning model. Eventually, the proposed model suffices to find the optimal number and siting for both DERs and DC feeders while ensuring the continuality of the DC feeders. The proposed model is tested in two MG-based distribution systems, and its effectiveness is validated by the results of numerical experiments.

scholarly journals A Mixed-Integer Convex Model for the Optimal Placement and Sizing of Distributed Generators in Power Distribution Networks

2021 ◽  
Vol 11 (2) ◽  
pp. 627
Author(s):  
Walter Gil-González ◽  
Alejandro Garces ◽  
Oscar Danilo Montoya ◽  
Jesus C. Hernández
Keyword(s):  
Power Distribution ◽  
Power Flow ◽  
Distribution Networks ◽  
Global Optimum ◽  
Optimal Placement ◽  
Mixed Integer ◽  
Power Distribution Networks ◽  
Distributed Generators ◽  
Second Order Cone ◽  
Proposed Model

The optimal placement and sizing of distributed generators is a classical problem in power distribution networks that is usually solved using heuristic algorithms due to its high complexity. This paper proposes a different approach based on a mixed-integer second-order cone programming (MI-SOCP) model that ensures the global optimum of the relaxed optimization model. Second-order cone programming (SOCP) has demonstrated to be an efficient alternative to cope with the non-convexity of the power flow equations in power distribution networks. Of relatively new interest to the power systems community is the extension to MI-SOCP models. The proposed model is an approximation. However, numerical validations in the IEEE 33-bus and IEEE 69-bus test systems for unity and variable power factor confirm that the proposed MI-SOCP finds the best solutions reported in the literature. Being an exact technique, the proposed model allows minimum processing times and zero standard deviation, i.e., the same optimum is guaranteed at each time that the MI-SOCP model is solved (a significant advantage in comparison to metaheuristics). Additionally, load and photovoltaic generation curves for the IEEE 69-node test system are included to demonstrate the applicability of the proposed MI-SOCP to solve the problem of the optimal location and sizing of renewable generators using the multi-period optimal power flow formulation. Therefore, the proposed MI-SOCP also guarantees the global optimum finding, in contrast to local solutions achieved with mixed-integer nonlinear programming solvers available in the GAMS optimization software. All the simulations were carried out via MATLAB software with the CVX package and Gurobi solver.

scholarly journals Soft-Switching Full-Bridge Converter with Multiple-Input Sources for DC Distribution Applications

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 775
Author(s):  
Sheng-Yu Tseng ◽  
Jun-Hao Fan
Keyword(s):  
Conversion Efficiency ◽  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Soft Switching ◽  
Maximum Output ◽  
Power Distribution Systems ◽  
Distribution Method ◽  
Dc Distribution ◽  
Multiple Input

Due to the advantages of power supply systems using the DC distribution method, such as a conversion efficiency increase of about 5–10%, a cost reduction of about 15–20%, etc., AC power distribution systems will be replaced by DC power distribution systems in the future. This paper adopts different converters to generate DC distribution system: DC/DC converter with PV arrays, power factor correction with utility line and full-bridge converter with multiple input sources. With this approach, the proposed full-bridge converter with soft-switching features for generating a desired voltage level in order to transfer energy to the proposed DC distribution system. In addition, the proposed soft-switching full-bridge converter is used to generate the DC voltage and is applied to balance power between the PV arrays and the utility line. Due to soft-switching features, the proposed full-bridge converter can be operated with zero-voltage switching (ZVS) at the turn-on transition to increase conversion efficiency. Finally, a prototype of the proposed full-bridge converter under an input voltage of DC 48 V, an output voltage of 24 V, a maximum output current of 21 A and a maximum output power of 500 W was implemented to prove its feasibility. From experimental results, it can be found that its maximum conversion efficiency is 92% under 50% of full-load conditions. It was shown to be suitable for DC distribution applications.

scholarly journals Design and Testing of a Low Voltage Solid-State Circuit Breaker for a DC Distribution System

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 338
Author(s):  
Leslie Tracy ◽  
Praveen Kumar Sekhar
Keyword(s):  
Solid State ◽  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Circuit Breaker ◽  
Solid State Circuit ◽  
Dc Distribution ◽  
High Side ◽  
Solid State Circuit Breaker

In this study, a low voltage solid-state circuit breaker (SSCB) was implemented for a DC distribution system using commercially available components. The design process of the high-side static switch was enabled through a voltage bias. Detailed functional testing of the current sensor, high-side switch, thermal ratings, analog to digital conversion (ADC) techniques, and response times of the SSCB was evaluated. The designed SSCB was capable of low-end lighting protection applications and tested at 50 V. A 15 A continuous current rating was obtained, and the minimum response time of the SSCB was nearly 290 times faster than that of conventional AC protection methods. The SSCB was implemented to fill the gap where traditional AC protection schemes have failed. DC distribution systems are capable of extreme faults that can destroy sensitive power electronic equipment. However, continued research and development of the SSCB is helping to revolutionize the power industry and change the current power distribution methods to better utilize clean renewable energy systems.

scholarly journals Efficiency Comparison of AC and DC Distribution Networks for Modern Residential Localities

2019 ◽  
Vol 9 (3) ◽  
pp. 582 ◽  
Author(s):  
Hasan Gelani ◽  
Faizan Dastgeer ◽  
Kiran Siraj ◽  
Mashood Nasir ◽  
Kamran Niazi ◽  
...  
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
System Modeling ◽  
Distribution Networks ◽  
Solar Irradiation ◽  
Energy Information Administration ◽  
Solar Pv ◽  
Dc Distribution ◽  
Efficiency Comparison

The paper investigates the system efficiency for power distribution in residential localities considering daily load variations. Relevant system modeling is presented. A mathematical model is devised, which is based on the data from the Energy Information Administration (EIA), USA, for analysis. The results reveal that the DC distribution system can present an equivalent or even better efficiency compared to the AC distribution network with an efficiency advantage of 2.3%, averaged over a day. Furthermore, the distribution systems are compared under various capacities of solar PV accounting for the effect of variation in solar irradiation over time.

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