scholarly journals Spatial Model of Optimization Applied in the Distributed Generation Photovoltaic to Adjust Voltage Levels

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7506
Author(s):  
José A. G. Cararo ◽  
João Caetano Caetano Neto ◽  
Wagner A. Vilela Vilela Júnior ◽  
Márcio R. C. Reis ◽  
Gabriel A. Wainer ◽  
...  
Keyword(s):  
Distributed Generation ◽  
Power Grid ◽  
Geographic Location ◽  
Voltage Level ◽  
Voltage Quality ◽  
Minimum Number ◽  
Optimized Allocation ◽  
Spatial Grids ◽  
Installed Capacity

The main objective of this work is to develop a methodology for analyzing the quality of the voltage level in the distribution power grid to identify and reduce the violations of voltage limits through the proposition of optimal points for the allocation of photovoltaic distributed generation. The methodology uses the geographic location of the power grid and its consumers to perform the grouping and classification in spatial grids of 100×100 m using the average annual consumption profile. The generated profiles, including the grid information, are sent to the photovoltaic distributed generation allocation algorithm, which, using an optimization process, identifies the geographic location, the required installed capacity, and the minimum number of photovoltaic generation units that must be inserted to minimize the violations of voltage limits, respecting the necessary restrictions. The entire proposal is applied in a real feeder with thousands of bars, whose model is validated with measurements carried out in the field. Different violations of voltage limits scenarios are used to validate the methodology, obtaining grids with better voltage quality after the optimized allocation of photovoltaic distributed generation. The proposal presents itself as a new tool in the work of adapting the voltage of the distribution power grid using photovoltaic distributed generation.

scholarly journals Induction Motor Drives Fed by an NPC Inverter with Unbalanced DC-Link

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1379 ◽  
Author(s):  
Umberto Abronzini ◽  
Ciro Attaianese ◽  
Matilde D’Arpino ◽  
Mauro Di Monaco ◽  
Giuseppe Tomasso
Keyword(s):  
Output Voltage ◽  
Harmonic Distortion ◽  
Voltage Regulation ◽  
Motor Drives ◽  
Operating Conditions ◽  
Switching Frequency ◽  
Voltage Level ◽  
Voltage Quality ◽  
Vector Modulation

Neutral Point Clamped (NPC) converters with n levels are traditionally controlled in such a way that the DC-link capacitors operate at 1/( n - 1) of the total DC-link voltage level. The voltage level across the DC-link capacitors has to be properly regulated by the capacitor unbalance control to contain the harmonic distortion of the converter output voltages. State-of-the-art modulation techniques address the problem of the DC-link voltage regulation for NPC inverters. However, they highly show reduced performance when unbalanced DC-link voltages are considered. In this paper, a novel Space Vector Modulation (SVM) is proposed for NPC converters with an unbalanced DC-link. At every modulation interval, the technique defines the optimal switching pattern by considering the actual unbalanced DC-link conditions. The proposed modulation allows improving the harmonic content of the NPC converter output voltage with respect to a traditional ML-SVM, when the same operating conditions are considered. As an extension, the proposed modulation technique will guarantee the same output voltage quality of a traditional ML-SVM with unbalanced DC-link, while improving the conversion efficiency thanks to a reduction of switching frequency.

scholarly journals PROPOSAL FOR MANAGING ELECTRIC ENERGY QUALITY IN THE LV GRID USING ON-LOAD TAP CHANGER WITH A STATIC SYNCHRONOUS COMPENSATOR

2018 ◽  
Vol 8 (2) ◽  
pp. 72-78
Author(s):  
Bartłomiej Mroczek ◽  
Karol Fatyga
Keyword(s):  
Reactive Power ◽  
Low Voltage ◽  
Power Grid ◽  
Electric Energy ◽  
Auxiliary Equipment ◽  
Static Synchronous Compensator ◽  
Voltage Quality ◽  
Tap Changer ◽  
Load Tap Changer

The paper proposes the use of auxiliary equipment in the low voltage network: an on-load tap changer and a static synchronous compensator (STATCOM) to improve the quality of energy supply to end users. As part of the research, a section of medium and low voltage power grid was modelled using Matlab & Simulink software, which was tested in three scenarios. The first scenario presents the operation of the power grid with the on-load tap changer installed in the transformer block. The second scenario uses the STATCOM for local reactive power compensation. Additionally, the third scenario is the combined work of the on-load tap-changer along with the STATCOM. According to the authors, the method discussed does not bring the expected results in the area of voltage quality improvement, indicating that further research is required, including tests with energy storage.

TECHNICAL REGULATION OF VOLTAGE QUALITY IN ELECTRICAL GRIDS WITH SOURCES OF DISTRIBUTED GENERATION

2016 ◽  
Vol 2016 (3) ◽  
pp. 55-57 ◽  
Author(s):  
A.F. Zharkin ◽  
◽  
V.O. Novsky ◽  
S.O. Palachov ◽  
◽  
...  
Keyword(s):  
Distributed Generation ◽  
Technical Regulation ◽  
Electrical Grids ◽  
Voltage Quality

scholarly journals Optimal Allocation of Large-Capacity Distributed Generation with the Volt/Var Control Capability Using Particle Swarm Optimization

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3112
Author(s):  
Donghyeon Lee ◽  
Seungwan Son ◽  
Insu Kim
Keyword(s):  
Particle Swarm Optimization ◽  
Electric Power ◽  
Distributed Generation ◽  
Optimal Allocation ◽  
Power Grid ◽  
Particle Swarm ◽  
Renewable Energy Resources ◽  
Swarm Optimization ◽  
Large Capacity ◽  
Electric Power Grid

Widespread interest in environmental issues is growing. Many studies have examined the effect of distributed generation (DG) from renewable energy resources on the electric power grid. For example, various studies efficiently connect growing DG to the current electric power grid. Accordingly, the objective of this study is to present an algorithm that determines DG location and capacity. For this purpose, this study combines particle swarm optimization (PSO) and the Volt/Var control (VVC) of DG while regulating the voltage magnitude within the allowable variation (e.g., ±5%). For practical optimization, the PSO algorithm is enhanced by applying load profile data (e.g., 24-h data). The objective function (OF) in the proposed PSO method considers voltage variations, line losses, and economic aspects of deploying large-capacity DG (e.g., installation costs) to transmission networks. The case studies validate the proposed method (i.e., optimal allocation of DG with the capability of VVC with PSO) by applying the proposed OF to the PSO that finds the optimal DG capacity and location in various scenarios (e.g., the IEEE 14- and 30-bus test feeders). This study then uses VVC to compare the voltage profile, loss, and installation cost improved by DG to a grid without DG.

Possible Influence of Geographic Location and Colony Counts on Guidelines for Diagnosis of Streptococcal Infections in Rheumatic Fever

PEDIATRICS ◽  
1972 ◽  
Vol 49 (4) ◽  
pp. 636-636
Author(s):  
Norman Lewak
Keyword(s):  
Rheumatic Fever ◽  
Medical Practice ◽  
Streptococcal Infection ◽  
Geographic Location ◽  
Economic Factors ◽  
Streptococcal Infections ◽  
The Public ◽  
The Future

In their "Guidelines for the Diagnosis of Streptococcal Infection" (Pediatrics, 48:573, 1971), Honikman and Massell did not specify whether the guidelines should vary by geographic location. Taking into consideration the economic factors mentioned by the authors, should the same guidelines apply to different areas of the country which have markedly different incidences of rheumatic fever? We are all aware that the public is (rightfully) taking a close look at the quality of medical practice. Practice audits appear to be a certainty in the future.

Uticaj solarne elektrane na kvalitet električne energije u niskonaponskoj distributivnoj mreži

2020 ◽  
Vol 22 (1-2) ◽  
pp. 137-144
Author(s):  
Hidajet Salkić ◽  
Amir Softić ◽  
Amer Salkić
Keyword(s):  
Power Quality ◽  
Negative Feedback ◽  
Electricity Market ◽  
Reactive Power ◽  
Electric Power System ◽  
Integrated System ◽  
Distributed Source ◽  
Voltage Quality ◽  
Number Of Customers

The electric power system, as an integrated system for transmission, distribution and consumption of electricity, is one of the most complex technical and economic systems today. Customers affect on the voltage quality of power network, but the network also has an impact on customers. All disturbances in the network can disrupt operation of the network and affect on operation of the customers, as well as reduce the level of efficiency and operation life or even seriously damage network. Number of customers is increasing every day, as well as proportion of customers who generate disturbances in the network and, at the same time, are sensitive to them. These circumstances impose the need for frequent monitoring of the network, so the analysis of power quality is not unjustified cost but extremely important and profitable investment. The quality of electricity, as part of the overall quality supply of electricity customers in deregulated conditions of liberal electricity market becomes significant regulatory parameter for network operators and a significant contracting parameter on the electricity market. Network operators are obliged to establish a system of individual measurements and a system of permanent monitoring of power quality parameters to determine the state and improve the parameters to the standardized level. Technical parameters are determined by the recommendations made at the international level and may, but do not need, be legally binding. Maintaining a certain level of voltage quality at some point of the network is the responsibility of electricity distributor. This task distributor executes by limiting of negative effects of producer/customer to the network. Therefore, each electricity producer/customer is obliged to reduce own negative feedback effects (injection of higher harmonics, taking of reactive power, emissions of flickers and loads unbalances) to a prescribed, prearranged, limited values. There are many norms that describe the quality of electricity, but in Europe the best known is EN50160 (issued by CENLEC). This paper presents the approach to measuring the voltage quality at the point of electricity delivery from distributed source into distribution network from the aspect of limiting the negative feedback of distributed source on the voltage quality.

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