scholarly journals The effects of LED light sources on the parameters defining the quality of electricity

2018 ◽  
Vol 19 ◽  
pp. 01006
Author(s):  
Andrzej Lange ◽  
Marian Pasko
Keyword(s):  
High Voltage ◽  
Power Factor ◽  
Low Voltage ◽  
Power Grid ◽  
Power Grids ◽  
Light Sources ◽  
Medium Voltage ◽  
Led Lights ◽  
Voltage Harmonics

The article presents the regulations and standards relating to the quality of electricity, with special emphasis on higher current and voltage harmonics in high-voltage, medium-voltage and low-voltage power grids and the power factor (PF). The parameters defining the quality of electricity consumed by modern LED bulbs for lighting homes, industrial premises such as offices and production halls, as well as roads and yards were measured and analyzed. The current waveforms for LED lights were presented upon connection to the power grid.

scholarly journals Novel Enhanced Modular Multilevel Converter for High-Voltage Direct Current Transmission Systems

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2257
Author(s):  
Dimitrios Vozikis ◽  
Fahad Alsokhiry ◽  
Grain Philip Adam ◽  
Yusuf Al-Turki
Keyword(s):  
High Voltage ◽  
Low Voltage ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Medium Voltage ◽  
High Voltage Direct Current ◽  
Current Transmission ◽  
The Cost ◽  
Voltage Harmonics ◽  
Chain Links

This paper proposes an enhanced modular multilevel converter as an alternative to the conventional half-bridge modular multilevel converter that employs a reduced number of medium-voltage cells, with the aim of improving waveforms quality in its AC and DC sides. Each enhanced modular multilevel converter arm consists of high-voltage and low-voltage chain-links. The enhanced modular multilevel converter uses the high-voltage chain-links based on medium-voltage half-bridge cells to synthesize the fundamental voltage using nearest level modulation. Although the low-voltage chain-links filter out the voltage harmonics from the voltage generated by the high-voltage chain-links, which are rough and stepped approximations of the fundamental voltage, the enhanced modular multilevel converter uses the nested multilevel concept to dramatically increase the number of voltage levels per phase compared to half-bridge modular multilevel converter. The aforementioned improvements are achieved at the cost of a small increase in semiconductor losses. Detailed simulations conducted in EMPT-RV and experimental results confirm the validity of the proposed converter.

scholarly journals Operation Modes of HV/MV Substations

2009 ◽  
Vol 25 (25) ◽  
pp. 81-86
Author(s):  
Josifs Survilo ◽  
Antons Kutjuns
Keyword(s):  
High Voltage ◽  
Low Voltage ◽  
Warm Season ◽  
Electrical Energy ◽  
Cold Season ◽  
Power Losses ◽  
Medium Voltage ◽  
The Third ◽  
Operation Modes ◽  
Mode 3

Operation Modes of HV/MV SubstationsA distribution network consists of high voltage grid, medium voltage grid, and low voltage grid. Medium voltage grid is connected to high voltage grid via substations with HV/MV transformers. The substation may contain one, mostly two but sometimes even more transformers. Out of reliability and expenditure considerations the two transformer option prevail over others mentioned. For two transformer substation, there may be made choice out of several operation modes: 1) two (small) transformers, with rated power each over 0.7 of maximum substation load, permanently in operation; 2) one (big) transformer, with rated power over maximum substation load, permanently in operation and small transformer in constant cold reserve; 3) big transformer in operation in cold season, small transformer-in warm one. Considering transformer load losses and no load losses and observing transformer loading factor β it can be said that the mode 1) is less advantageous. The least power losses has the mode 3). There may be singled out yet three extra modes of two transformer substations: 4) two big transformers in permanent operation; 5) one big transformer permanently in operation and one such transformer in cold reserve; 6) two small transformers in operation in cold season of the year, in warm season-one small transformer on duty. At present mostly two transformers of equal power each are installed on substations and in operation is one of them, hence extra mode 5). When one transformer becomes faulty, it can be changed for smaller one and the third operation mode can be practiced. Extra mode 4) is unpractical in all aspects. The mode 6) has greater losses than the mode 3) and is not considered in detail. To prove the advantage of the third mode in sense of power losses, the notion of effective utilization time of power losses was introduced and it was proven that relative value of this quantity diminishes with loading factor β. The use of advantageous substation option would make it possible to save notable amount of electrical energy but smaller transformer lifetime of this option must be taken into account as well.

scholarly journals TO SURVEY POWER QUALITY OF HIGH VOLTAGE KEY-CUSTOMER BY USING VOLTAGE EVENT RECORD

2020 ◽  
Vol 5 (9) ◽  
pp. 30-43
Author(s):  
Yen-Ming Tseng ◽  
Hsi-Shan Huang ◽  
Chen JiQuan ◽  
Wang Xuefei ◽  
Chen Han ◽  
...  
Keyword(s):  
Power Quality ◽  
High Voltage ◽  
Low Voltage ◽  
Economic Losses ◽  
Data Sets ◽  
Event Data ◽  
Voltage Swell ◽  
Event Record ◽  
Key Customer

According to IEEE-1159 definition and classification of power quality of applying at supplyside and demand-side of power system to evaluate the power quality of high voltage keycustomer and using the voltage events record (VER) in low voltage level supply. Which voltage parameter set of VER with specific software Event View software by Fluke and can collect event data, plot graphic of event data sets that can using the data mining skill to analysis the voltage swell, voltage sag, power outage, frequency events and three phase load unbalance of high voltage key-customer. By abnormal voltage event statistics with discriminated by quantization of high voltage key-customer which can evaluate the own power quality and an also provide reference for quality requirements for related semiconductor factories with higher demand that can avoid the significant effect the economic losses.

scholarly journals A Four-Winding Inductive Filtering Transformer to Enhance Power Quality in a High-Voltage Distribution Network Supplying Nonlinear Loads

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2021 ◽  
Author(s):  
Yuehui Chen ◽  
Zhao Huang ◽  
Zhenfeng Duan ◽  
Pengwu Fu ◽  
Guandong Zhou ◽  
...  
Keyword(s):  
Power Quality ◽  
High Voltage ◽  
Reactive Power ◽  
Low Voltage ◽  
Distribution Network ◽  
Nonlinear Loads ◽  
The Public ◽  
Passive Filters ◽  
Grid Side

This paper solves the problem of reactive power and harmonics compensation in a high-voltage (HV) distribution network supplying nonlinear loads. An inductive filtering (IF) approach where passive filters connect to the filtering winding of a four-winding inductive filtering transformer (FW-IFT) is presented to enhance the power quality of the public grid. This method can not only greatly suppress harmonic currents of the medium and/or low-voltage (LV) side, but also prevent them from flowing into the public grid. The new main circuit topology, where the FW-IFT has specific filtering winding by adopting the ampere-turn balance of the transformer, is presented. On the basis of the structure of the FW-IFT, the magnetic potential balanced equation and inductive filtering technology, its equivalent circuit and mathematical model are established, and the filtering performances are analyzed in detail. Simulation and experimental results rated at SN-10/0.38 of the FW-IFT are presented to prove the efficacy of the comprehensive enhancement of power quality on the grid side.

scholarly journals A Resilience Toolbox and Research Design for Black Sky Hazards to Power Grids

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Dmitry Borisoglebsky ◽  
Liz Varga
Keyword(s):  
Simulation Model ◽  
Business Processes ◽  
Power Grid ◽  
Multicriteria Decision Making ◽  
Two Dimensions ◽  
Power Grids ◽  
Research Approach ◽  
Grid Simulation ◽  
The Difference

A structured collection of tools for engineering resilience and a research approach to improve the resilience of a power grid are described in this paper. The collection is organized by a two-dimensional array formed from typologies of power grid components and business processes. These two dimensions provide physical and operational outlooks, respectively, for a power grid. The approach for resilience research is based on building a simulation model of a power grid which utilizes a resilience assessment equation to assess baseline resilience to a hazards’ profile, then iteratively selects a subset of tools from the collection, and introduces these as interventions in the power grid simulation model. Calculating the difference in resilience associated with each subset supports multicriteria decision-making to find the most convenient subset of interventions for a power grid and hazards’ profile. Resilience is an emergent quality of a power grid system, and therefore resilience research and interventions must be system-driven. This paper outlines further research required prior to the practical application of this approach.

scholarly journals Design of power substation placement with GIS tracing tools

Vestnik IGEU ◽  
2019 ◽  
pp. 75-83 ◽  
Author(s):  
А.В. Gadalov ◽  
S.V. Kosyakov
Keyword(s):  
Low Voltage ◽  
Power Grid ◽  
Distribution Networks ◽  
Power Lines ◽  
Electrical Networks ◽  
Voltage Distribution ◽  
Transformer Substation ◽  
Urban Distribution ◽  
Gis Environment

Analytical methods that are currently used to determine transformer substation placement in the process of planning the development of low-voltage distribution networks are based on calculating the lengths of future power lines by Euclidean distance, or methods for comparing several alternative placement options taking into account the routes of power lines. Assumptions made in this case lead to the fact that for the selected location of the substation, the total cost of the power lines connected to it may exceed the possible minimum. The use of modern GIS technologies allows simulating the routes of laying power lines on the map bypassing the existing obstacles or finding the cheapest routes for crossing them. These opportunities can be used to improve the quality of designing urban distribution networks through minimizing the construction cost of new power lines. However, the methods of organizing the solution to such a design problem have not yet found practical applications. The aim of the work is to develop a practical method of designing the placement of power substations in the GIS environment and its verification using real data. The paper uses methods of spatial modeling in the GIS environment, including methods of overlay, finding optimal paths on graphs and power grid inventory, as well as discrete optimization methods. A method of computer-aided design of transformer substation placement in urban distribution low-voltage networks is proposed and implemented as a GIS software module, which allows finding the optimal options of the placement cost at the stages of network scheme selection. The paper presents the results of the method analysis based on studying the design of the power grid scheme of Ivanovo city quarters as an example. The results confirm the possibility of using GIS to improve the quality of decisions on the choice of placement of low voltage distribution substations when designing urban electrical networks and can be used in the electrical networks CAD.

Research and Analysis of Reliability of Power Grid SVG Master Circuit in Rural Areas

2015 ◽  
Vol 713-715 ◽  
pp. 1299-1301
Author(s):  
Hong Kai Li ◽  
Wei Li Wang ◽  
Jin Xing Wang ◽  
Shu Han Wang ◽  
Li Hong
Keyword(s):  
Rural Areas ◽  
Low Voltage ◽  
Power Grid ◽  
Reliability Estimation ◽  
Power Grids ◽  
Reactive Compensation ◽  
Line Loss ◽  
Made In China ◽  
Safety And Stability ◽  
Made In

Problems such as low voltage and big line loss have long existing in the power grid in rural areas of China. In recent years, some province and cities have improved voltage and reduced line loss by installing SVG at substations in rural power grids, and the effect is remarkable.With great compensation capacity and a good variety of modes of compensation, SVG is sure to replace old reactive compensation devices in rural power grid in future, which requires evaluation and analysis of SVG reliability so as to guarantee safety and stability of the power grid. However, now no research or analysis has been made in China on SVG reliability in rural power grids, which affects wide promotion of SVG in rural power grids.Under the background of Liaoning Power Grid 10kV/±5Mvar Chain SVG, this paper analyzes the reliability of k/n (G) system model of SVG master circuit structure, improving the accuracy of system reliability estimation. The estimation matches the operation outcome, thus providing data basis for the feasibility of SVG’s wide application in rural power grid in future.

Benefits of High Voltage SiC Applications in Medium Voltage Power Distribution Grids

2018 ◽  
Vol 924 ◽  
pp. 875-878 ◽  
Author(s):  
Shi Qi Ji ◽  
Xiao Jie Shi ◽  
Zhe Yu Zhang ◽  
Wen Chao Cao ◽  
Fred Wang
Keyword(s):  
High Voltage ◽  
Power Distribution ◽  
Low Voltage ◽  
System Stability ◽  
System Level ◽  
Medium Voltage ◽  
Low Voltage Ride Through ◽  
Grid Interface ◽  
Potential Benefits ◽  
Distribution Grids

This paper evaluates potential benefits of high voltage (HV) SiC devices in medium voltage (MV) distribution grids. The MV microgrid, that HV SiC devices can benefit most, is selected as the “killer application” and focused in this paper. The design and simulation are carried out to compare Si-and SiC-based grid interface converters for the quantitative benefit assessment both at converter level and system level. The SiC-based converter has significant benefits in weight and size, and shows enhanced performance and functionality on power quality, system stability and low voltage ride through (LVRT) as well.

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