scholarly journals Power Quality Measurement and Active Harmonic Power in 25 kV 50 Hz AC Railway Systems

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5698
Author(s):  
Yljon Seferi ◽  
Steven M. Blair ◽  
Christian Mester ◽  
Brian G. Stewart
Keyword(s):  
Power Quality ◽  
Quality Measurement ◽  
Electrical Energy ◽  
Active Power ◽  
Time Interval ◽  
Time Varying ◽  
Electrical Networks ◽  
Measurement Instruments ◽  
Railway Systems ◽  
The Impact

Railway electrical networks rated at 25 kV 50 Hz are characterised by significant levels of voltage and current harmonics. These frequency components are also time varying in nature due to the movement of trains and changing operational modes. Processing techniques used to evaluate harmonic results, although standardised, are not explicitly designed for railway applications, and the smoothing effect that the standard aggregation algorithms have on the measured results is significant. This paper analyses the application accuracy of standardised power quality (PQ) measurement algorithms, when used to measure and evaluate harmonics in railway electrical networks. A shorter aggregation time interval is proposed for railway power quality measurement instruments, which offers more accurate estimated results and improved tracking of time varying phenomena. Harmonic active power present in railway electrical networks is also evaluated in order to quantify the impact it has on the energy accumulated by electrical energy meters installed on-board trains. Analysis performed on 12 train journeys shows significant levels of non-fundamental active power developed for short periods of time. As an energy meter will inadvertently absorb the financial cost of non-fundamental energy produced by other trains or other external power flows, results are provided to support recommendations for future standards to measure only fundamental frequency energy within train energy measurement meters.

The Impact of US Monetary Growth on Bitcoin Trading Volume in the Current Economic Uncertainty

2020 ◽  
pp. 493-509
Author(s):  
İsmail Canöz
Keyword(s):  
Causal Relationship ◽  
Trading Volume ◽  
Causal Effect ◽  
Study Data ◽  
Time Interval ◽  
Time Varying ◽  
Economic Uncertainty ◽  
Causality Test ◽  
Data Set ◽  
The Impact

This study examines the effect of US monetary growth on Bitcoin trading volume. To achieve this purpose, firstly, the symmetric causality test is used. Following this test, another symmetric causality test is used to reveal a time-varying causal effect between variables. The data set covers the period from July 2010 to July 2019. The results of the first symmetric causality test, which considers the time interval of the study data as a whole, show that there is no causal relationship between variables. According to the results of the second causality test, these support the previous results substantially. However, an interesting detail is the causal relationship between variables for the period between April 2019 and July 2019. The reason for this relationship could be that investors who are indecisive during the current economic uncertainty add Bitcoin to their portfolios in response to the Federal Reserve's decisions.

scholarly journals Simulation and Analysis of a Three-phase Shunt Active Power Filter

2020 ◽  
pp. 162-166
Keyword(s):  
Power Systems ◽  
Power Quality ◽  
Harmonic Distortion ◽  
Active Power Filter ◽  
Active Power ◽  
Shunt Active Power Filter ◽  
Power Filter ◽  
Three Phase ◽  
Non Linear ◽  
The Impact

This paper presents the simulation-based study and results of a three-phase shunt active power filter (SAPF) for power quality improvement. The power quality of the power systems is degraded because of the presence of non-linear loads at the consumer end. The SAPF can reduce the impact of harmonics caused by the non-linear loads. The analyzed SAPF system is modeled and simulated using MATLAB-Simulink workspace. The ultimate goal of this study is to improve the total harmonic distortion of the system as per the standards defined by IEEE-519.

scholarly journals On the influence of electric power quality on the decimation of currents and voltages of utility frequency

2021 ◽  
Vol 288 ◽  
pp. 01022
Author(s):  
Gennady Vagin ◽  
Alexander Kulikov ◽  
Alexander Sevostyanov ◽  
Anatoly Fitasov
Keyword(s):  
Electric Power ◽  
Power Quality ◽  
Harmonic Component ◽  
Electric Power Industry ◽  
Digital Signal ◽  
Electrical Energy ◽  
Sampling Frequency ◽  
Electrical Network ◽  
Electrical Networks ◽  
Electric Power Quality

The electric power industry cannot develop without analyzing the factors that affect the shape of currents and voltages when determining the parameters of the electric network mode in the context of the introduction of modern means of intellectualization into the structure of power supply systems. The share of equipment affecting the electric power quality reaches 90% in modern electrical networks. This leads to the appearance of noise in the network that reduces the quality of electrical energy, voltage distortion by higher harmonic components in particular, and affects the adequacy of the parameters of the electrical network adopted by automatic control devices. The article presents the results of digital signal processing containing distortions in the form of a harmonic component with a decrease in the sampling frequency. It is shown that a decrease in the sampling frequency does not exclude the effect of higher harmonics on the result of processing signals, including high-frequency distortions.

Micro-Grid Power Quality Management

2015 ◽  
Vol 713-715 ◽  
pp. 1335-1342
Author(s):  
Zhi Qiang Gao ◽  
Hua Yu Chu ◽  
Liang Meng ◽  
Si Qing Sheng ◽  
Zhong Ji Sun ◽  
...  
Keyword(s):  
Power Quality ◽  
Control Method ◽  
Active Power Filter ◽  
Active Power ◽  
Grid Technology ◽  
Power Filter ◽  
Micro Grid ◽  
Simulation Results ◽  
The Impact

As distribute power generation and micro-grid technology develops, more and more researchers attach importance to the problems of power quality in micro-grid, especially the problem of harmonic. This paper describes the impact and harm harmonic has on the power quality of the power grid. It introduces a revised method of managing micro-grid harmonics which uses an active power filter (APF), and the control method of APF is different from the traditional one. It also establishes the simulation model of micro-grid, analyze the simulation results and experiment in actual micro-grid to verify the effectiveness of the proposed method.

scholarly journals Analysis of the influence of non-sinusoidal and unbalanced network modes on induction motors

2021 ◽  
Vol 289 ◽  
pp. 01002
Author(s):  
Ngo Van Cuong ◽  
Lidiia I. Kovernikova
Keyword(s):  
Power Systems ◽  
Power Quality ◽  
Induction Motors ◽  
Electrical Power ◽  
Electrical Energy ◽  
Operating Conditions ◽  
Premature Aging ◽  
Electrical Network ◽  
Electrical Networks ◽  
Electrical Power Systems

The parameters of electrical network modes do not correspond the requirements GOST 32144-2013 of Russian and the National technical regulation of Vietnam. In real operating conditions in electrical networks in non-sinusoidal and unbalanced modes there are harmonic components of voltages and currents as well as voltages and currents of negative sequence. They cause additional losses of active power, which leads to additional heating and causes premature aging of the insulation, and as the result, the reduction in the service life of induction motors. Currently, we see that the process of formation of intelligent electrical power systems is underway. Systems for continuous monitoring of power quality indices and parameters of electrical systems modes are being developed. These systems can be supplemented with programs for calculating characteristics that issue the warning when the unfavorable influence of the parameters of non-sinusoidal and unbalanced modes is detected on various electrical equipment of both electrical power systems and consumers of electrical energy. The paper provides an overview of the characteristics used to analyze, assess and predict the influence of poor power quality associated with non-sinusoidal and unbalanced of currents and voltages on induction motors. A computer program was developed to calculate these characteristics. The program was used to study the influence of non-sinusoidal and unbalanced modes on the induction motors of the coal sorting plant of the Vietnamese company “Cua Ong-Vinacomin”.

Power Quality and Resonances in Power Supply Systems with Non-Sinusoidal Loads

2017 ◽  
Vol 25 ◽  
pp. 143-150
Author(s):  
Yurii Papaika ◽  
Oleksandra Lysenko ◽  
Grzegorz Kosobudzki
Keyword(s):  
Spectral Analysis ◽  
Power Quality ◽  
Coal Mine ◽  
Power Supply ◽  
Electromagnetic Compatibility ◽  
Electrical Networks ◽  
Voltage Quality ◽  
The Impact ◽  
Supply Systems

The stress is made on the necessity to take into account the impact of higher while analysing the quality of voltage in power supply systems of coal mine. The process of resonances in power supply systems is explained in terms of physics, the sources generating this kind of interference are described. Mathematical dependences that allow to identify resonances in power supply systems are provided. The focus is placed on the feasibility of using spectral analysis in computations. To investigate the understudied aspects of voltage quality and electromagnetic compatibility and provide mathematical description for the analysis of resonances in electrical networks with powerful non-sinusoidal loads.

Waveform Measurement and Analysis of Common Household Appliances

2014 ◽  
Vol 599-601 ◽  
pp. 767-775
Author(s):  
Xin Tong Wang ◽  
Xiao Bo Wang ◽  
Hui Zhong Zhang
Keyword(s):  
Power Quality ◽  
Electrical Energy ◽  
Important Indicator ◽  
Household Appliances ◽  
Harmonic Control ◽  
Power Company ◽  
Harmonic Study ◽  
Electricity Power ◽  
The Right ◽  
The Impact

Electricity power companies have the obligation to provide qualified electrical energy to the power user, the same as electricity customers, the power company claims to provide qualified energy, electricity customers are obliged to choose the right appliances to minimize the impact on the power quality of the power system . Higher harmonics is an important indicator of the impact of power quality, household appliances majority of non-linear loads, the use of the process will produce high harmonics, although the power is not, but a huge number, pooled together, will still PQ great impact. Therefore, the measurement of electrical waveforms common household appliances, will harmonic analysis, harmonic control, or other harmonic study is instructive.

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