scholarly journals Feasibility Analysis of a DC Distribution System for a 6 kW Photovoltaic Installation in Ireland

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6265
Author(s):  
Meshari Alshammari ◽  
Maeve Duffy
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
High Efficiency ◽  
Renewable Energy Sources ◽  
Annual Data ◽  
The West ◽  
Dc Distribution ◽  
National School ◽  
Recent Developments ◽  
Micro Grids

Recent developments in micro-grids have led to increased interest in DC distribution due to its high efficiency in distributing energy from renewable energy sources to DC loads. This paper seeks to analyse the performance of AC and DC systems in a relatively large-sized 6 kW PV installation to determine the level of improvement in efficiency provided by DC distribution and to identify methods for further improvement. Baseline annual data for the AC system were collected from a live installation on a national school in Inis Oirr, an island off the west coast of Ireland. The results indicate that usage of a DC distribution system has the potential to reduce system losses by up to 50% as well as the ability for an annual saving in grid energy of 5% compared to the existing AC system. Moreover, the analysis reveals that DC outperforms AC distribution more in spring and autumn, when power consumption is comparable to the system production, but there is less impact in summer, when PV production is significantly higher than demand. These findings provide insights into the benefits of future DC distribution systems in individual buildings and in larger-scale micro-grids.

scholarly journals A Two-Step State Estimation Algorithm for Hybrid AC-DC Distribution Grids

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1967
Author(s):  
Gaurav Kumar Roy ◽  
Marco Pau ◽  
Ferdinanda Ponci ◽  
Antonello Monti
Keyword(s):  
State Estimation ◽  
Distribution System ◽  
Renewable Energy Sources ◽  
Estimation Algorithm ◽  
The State ◽  
Second Step ◽  
Distribution Grid ◽  
Dc Distribution ◽  
Attractive Option ◽  
Distribution Grids

Direct Current (DC) grids are considered an attractive option for integrating high shares of renewable energy sources in the electrical distribution grid. Hence, in the future, Alternating Current (AC) and DC systems could be interconnected to form hybrid AC-DC distribution grids. This paper presents a two-step state estimation formulation for the monitoring of hybrid AC-DC grids. In the first step, state estimation is executed independently for the AC and DC areas of the distribution system. The second step refines the estimation results by exchanging boundary quantities at the AC-DC converters. To this purpose, the modulation index and phase angle control of the AC-DC converters are integrated into the second step of the proposed state estimation formulation. This allows providing additional inputs to the state estimation algorithm, which eventually leads to improve the accuracy of the state estimation results. Simulations on a sample AC-DC distribution grid are performed to highlight the benefits resulting from the integration of these converter control parameters for the estimation of both the AC and DC grid quantities.

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 Optimal Harmonic Mitigation in Distribution Systems with Inverter Based Distributed Generation

2021 ◽  
Vol 11 (2) ◽  
pp. 774 ◽  
Author(s):  
Ahmed S. Abbas ◽  
Ragab A. El-Sehiemy ◽  
Adel Abou El-Ela ◽  
Eman Salah Ali ◽  
Karar Mahmoud ◽  
...  
Keyword(s):  
Power Quality ◽  
Distributed Generation ◽  
Distribution System ◽  
Distribution Systems ◽  
Renewable Energy Sources ◽  
Harmonic Distortion ◽  
Planning Problem ◽  
Voltage Profile ◽  
Harmonic Mitigation ◽  
The Impact

In recent years, with the widespread use of non-linear loads power electronic devices associated with the penetration of various renewable energy sources, the distribution system is highly affected by harmonic distortion caused by these sources. Moreover, the inverter-based distributed generation units (DGs) (e.g., photovoltaic (PV) and wind turbine) that are integrated into the distribution systems, are considered as significant harmonic sources of severe harmful effects on the system power quality. To solve these issues, this paper proposes a harmonic mitigation method for improving the power quality problems in distribution systems. Specifically, the proposed optimal planning of the single tuned harmonic filters (STFs) in the presence of inverter-based DGs is developed by the recent Water Cycle Algorithm (WCA). The objectives of this planning problem aim to minimize the total harmonic distortion (THD), power loss, filter investment cost, and improvement of voltage profile considering different constraints to meet the IEEE 519 standard. Further, the impact of the inverter-based DGs on the system harmonics is studied. Two cases are considered to find the effect of the DGs harmonic spectrum on the system distortion and filter planning. The proposed method is tested on the IEEE 69-bus distribution system. The effectiveness of the proposed planning model is demonstrated where significant reductions in the harmonic distortion are accomplished.

scholarly journals Application-Oriented Reactive Power Management in German Distribution Systems Using Decentralized Energy Resources

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4949
Author(s):  
Haonan Wang ◽  
Markus Kraiczy ◽  
Denis Mende ◽  
Sebastian Stöcklein ◽  
Martin Braun
Keyword(s):  
Power Management ◽  
Distribution System ◽  
Distribution Systems ◽  
Reactive Power ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Measurement Data ◽  
Power Exchange ◽  
High Investment ◽  
Decentralized Energy

Due to higher penetration of renewable energy sources, grid reinforcements, and the utilization of local voltage control strategies, a significant change in the reactive power behavior as well as an increased demand for additional reactive power flexibility in the German power system can be predicted. In this paper, an application-oriented reactive power management concept is proposed, which allows distribution system operators (DSO) to enable a certain amount of reactive power flexibility at the grid interfaces while supporting voltage imitations in the grid. To evaluate its feasibility, the proposed concept is applied for real medium voltage grids in the south of Germany and is investigated comprehensively in different case studies. The results prove the feasibility and reliability of the proposed concept, which allows the DSO to control the reactive power exchange at grid interfaces without causing undesired local voltage problems. In addition, it can be simply adjusted and widely applied in real distribution grids without requiring high investment costs for complex information and communication infrastructures. As a significant contribution, this study provides an ideal bridging solution for DSOs who are facing reactive power issues but have no detailed and advanced monitoring system for their grid. Moreover, the comprehensive investigations in this study are performed in close cooperation with a German DSO, based on a detailed grid model and real measurement data.

scholarly journals Modern trends of the world market of electrical equipment

2021 ◽  
pp. 5-9
Author(s):  
Tetiana AVERIKHINA ◽  
Maryna BURIACHENKO ◽  
Valeriia VASYLIEVA
Keyword(s):  
Renewable Energy ◽  
Smart Grid ◽  
Distribution System ◽  
Distribution Systems ◽  
Renewable Energy Sources ◽  
Electrical Equipment ◽  
World Market ◽  
Global Market ◽  
The World ◽  
Transmission And Distribution

Introduction. The world market of electrical equipment is developing very fast. There are many companies in the market that sell electrical equipment, among them there are companies that occupy leading positions. Today, the world market of energy engineering is estimated at 87 billion dollars per year, based on the structural dynamics of growth, the annual volume can reach 110-115 billion dollars per year until 2025. The global market for energy equipment service in 2020 is 31.7 billion dollars, including: LTSA (long-term service) 47 %, modernization – 20 %, field service – 24 %, engineering – 9 %. The purpose of the paper is to analyze the world market of electrical equipment, determine sales, business growth. The list of leaders in electrical equipment on the world market is considered. Results. The main trends in the world today are the following areas: development of DC transmission system, cable lines for underwater laying and cable for connections of renewable energy sources to reduce energy transmission costs through the capabilities of existing transmission lines, through network voltages and innovative design solutions and installation methods. The amendment for these trends shows us the world leaders in the electrical market, such as Legrand, Schneider Electric, ABB, Siemens, DEKraft, SASSIN, EKF, etc., R&D costs are 3.5–5 % of profits (over 60 years). Thus, we can conclude that the global market for cable networks is developing rapidly. This market is expected to grow in the development of smart grid technologies, renewable energy generation and initiatives to modernize the transmission and distribution system. Conclusion. That the global cable ladder market is developing rapidly. This market is expected to grow in the development of smart grid technologies, renewable energy cultivation and government initiatives to modernize transmission and distribution systems.

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.

scholarly journals Robust Stability Control for Electric Vehicles Connected to DC Distribution Systems

2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Teng ◽  
Yuejiao Wang ◽  
Shumin Sun ◽  
Yan Cheng ◽  
Peng Yu ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Voltage Stability ◽  
Stability Control ◽  
Power Distribution Systems ◽  
Power Distribution System ◽  
Dc Power ◽  
Dc Distribution

DC power distribution systems will play an important role in the future urban power distribution system, while the charging and discharging requirements of electric vehicles have a great impact on the voltage stability of the DC power distribution systems. A robust control method based on H∞ loop shaping method is proposed to suppress the effect of uncertain integration on voltage stability of DC distribution system. The results of frequency domain analysis and time domain simulation show that the proposed robust controller can effectively suppress the DC bus voltage oscillation caused by the uncertain integration of electric vehicle, and the robustness is strong.

scholarly journals Reliability worth Assessment of Active Distribution System Considering Protective Devices and Multiple Distributed Generation Units

2018 ◽  
Vol 7 (2) ◽  
pp. 111
Author(s):  
Subramanya Sarma S ◽  
V. Madhusudhan ◽  
V. Ganesh
Keyword(s):  
Distributed Generation ◽  
Distribution System ◽  
Distribution Systems ◽  
Renewable Energy Sources ◽  
Distribution Networks ◽  
Research Area ◽  
Test System ◽  
Primary Concern ◽  
Reliability Indices ◽  
New Research

<p>Reliability worth assessment is a primary concern in planning and designing of electrical distribution systems those operate in an economic manner with minimal interruption of electric supply to customer loads. Renewable energy sources (RES) based Distributed Generation (DG) units can be forecasted to penetrate in distribution networks due to advancement in their technology. The assessment of reliability worth of DG enhanced distribution networks is a relatively new research area. This paper proposes a methodology that can be used to analyze the reliability of active distribution systems (DG enhanced distribution system) and can be applied in preliminary planning studies to compute the reliability indices and statistics. The reliability assessment in this work is carried out with analytical approach applied on a test system and simulated results validate that installation of distributed generators can improve the distribution system reliability considerably.</p>

scholarly journals Combined Operation of AC and DC Distribution System with Distributed Generation Units

2010 ◽  
Vol 61 (4) ◽  
pp. 193-204 ◽  
Author(s):  
Reza Noroozian ◽  
Mehrdad Abedi ◽  
Gevorg Gharehpetian
Keyword(s):  
Power Quality ◽  
Distributed Generation ◽  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Control Technique ◽  
Power Distribution System ◽  
Dc Distribution ◽  
Combined Operation ◽  
Ac Systems

Combined Operation of AC and DC Distribution System with Distributed Generation Units This paper presents a DC distribution system which has been supplied by external AC systems as well as local DG units in order to demonstrate an overall solution to power quality issue. In this paper, the proposed operation method is demonstrated by simulation of power transfer between external AC systems, DG units, AC and DC loads. The power flow control in DC distribution system has been achieved by network converters and DG converters. Also, the mathematical model of the network, DG and load converters are obtained by using the average technique, which allows converter systems accurately simulated and control strategies for this converters is achieved. A suitable control strategy for network converters has been proposed that involves DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control technique has been proposed for DG converters. In this paper, a novel control system based on stationary and synchronously rotating reference frame has been proposed for load converters for supplying AC loads connected to the DC bus by balanced voltages. The several case studies have been studied based on proposed methods. The simulation results show that DC distribution systems including DG units can improve the power quality at the point of common coupling (PCC) in the power distribution system or industrial power system.

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