Consideration of Nonsinusoidal/Unbalanced Operating Conditions of a Municipal Electric Network for Calculating the Current Level through the Neutral Conductor

2021 ◽  
Vol 1 (1) ◽  
pp. 35-43
Author(s):  
Mukhammadzhon М. KAMOLOV ◽  
◽  
Sagid A. АBDULKERIMOV ◽  
Khurshed B. NAZIROV ◽  
Shokhin D. DZHURAEV ◽  
...  
Keyword(s):  
Harmonic Component ◽  
Operating Conditions ◽  
Electric Networks ◽  
Electric Network ◽  
Three Phase ◽  
Zero Sequence ◽  
Flow Through ◽  
Higher Harmonic ◽  
Harmonic Components ◽  
Electric Loads

During the operation of 0.4 kV electric networks, asymmetry of currents and voltages is unavoidable. As is known, unbalanced operation of 0.4 kV networks is stemming from nonuniform distribution of loads between the phases. This results in that a fundamental frequency zero-sequence current will flow through the neutral conductor in a four-wire three-phase electric network. On the other hand, during balanced operation of a four-wire electric network containing loads with a nonlinear volt-ampere characteristic, higher harmonic currents multiple to three are summed in the neutral conductor. Therefore, it is of relevance to analyze unbalanced operating conditions of a four-wire electric network containing loads with a nonlinear volt-ampere characteristic. The article presents the characteristics of a municipal load for analyzing unbalanced/nonsinusoidal conditions of its operation. For carrying out full-valued assessment of unbalanced operating conditions of a four-wire electric network, a simulation model of a 0.4 kV network section containing a nonsinusoidal load is developed. It is shown that during unbalanced operation of an electric network containing electric loads with a nonlinear volt-ampere characteristic it is recommended to take into account zero-sequence current higher harmonic components that are not multiple to three. An algorithm for calculating the neutral conductor current harmonic component for determining the cable temperature rating is developed.

Statistical Correlation Between the Crankshaft’s Speed Variation and Engine Performance—Part I: Theoretical Model

2003 ◽  
Vol 125 (3) ◽  
pp. 791-796 ◽  
Author(s):  
D. Taraza
Keyword(s):  
Statistical Model ◽  
Statistical Approach ◽  
Harmonic Component ◽  
Engine Performance ◽  
Statistical Correlation ◽  
Gas Pressure ◽  
Operating Conditions ◽  
Crank Angle ◽  
The Mean ◽  
Harmonic Components

The goal of this two-part paper is to develop a methodology using the variation of the measured crankshaft speed to calculate the mean indicated pressure (MIP) of a multicylinder engine and to detect cylinders that are lower contributors to the total engine output. Both the gas pressure torque and the crankshaft’s speed are, under steady-state operating conditions, periodic functions of the crank angle and may be expressed by Fourier series. For the lower harmonic orders, the dynamic response of the crankshaft approaches the response of a rigid body and that makes it is possible to establish correlations between the amplitudes and phases of the corresponding harmonic orders of the crankshaft’s speed and of the gas pressure torque. The inherent cycle-to-cycle variation in the operation of the cylinders requires a statistical approach to the problem. The first part of the paper introduces the statistical model for a harmonic component of the gas pressure torque and determines the correlation between the amplitudes and phases of the harmonic components of the gas pressure torque and the MIP of the engine. In the second part of the paper the statistical model is used to calculate the MIP and to detect deficient cylinders in the operation of a six-cylinder four-stroke diesel engine.

scholarly journals Sensorless Control for Non-Sinusoidal Five-Phase Interior PMSM Based on Sliding Mode Observer

2021 ◽  
Vol 23 (6) ◽  
pp. 445-454
Author(s):  
Youssouf Mini ◽  
Ngac Ky Ngac Ky ◽  
Eric Semail
Keyword(s):  
Control Strategy ◽  
Sliding Mode ◽  
Sensorless Control ◽  
Harmonic Component ◽  
Sliding Mode Observer ◽  
Third Harmonic ◽  
The Third ◽  
Three Phase ◽  
Interior Permanent Magnet ◽  
Harmonic Components

This paper proposes a sensorless control strategy based on Sliding Mode Observer (SMO) for a Five-phase Interior Permanent Magnet Synchronous Machine (FIPMSM), with a consideration of the third harmonic component. Compared to conventional three-phase machines, the third harmonic of back electromotive force (back-EMF) contains more information. Thus, in this paper, the first and third harmonic components of the five-phase machine are considered to estimate the rotor position which is necessary for the vector control. Simulation results are shown to verify the feasibility and the robustness of the proposed sensorless control strategy.

scholarly journals The impact of the larger number of non-linear consumers on the quality of electricity

2019 ◽  
Vol 32 (3) ◽  
pp. 369-385
Author(s):  
Enver Agic ◽  
Damir Sljivac ◽  
Bakir Agic
Keyword(s):  
Total Duration ◽  
Harmonic Component ◽  
Simulation Models ◽  
Voltage Level ◽  
Harmonic Content ◽  
Three Phase ◽  
Harmonic Components ◽  
Parallel Filter ◽  
The Impact

Theoretically this paper will explain the formation of higher harmonic components in the electricity network, their causes, consequences on consumers and the ways of their elimination. Transformer role in the Dyg connection will be explained on the concrete example. For a specific example the waveform of primary (R) phase at 10 kV voltage level, the current of the secondary (r) phase and the neutral conductor at the 0.4 kV voltage level will be determined as shown in the concrete example in the work. Harmonic content will be determined up to 15 harmonics and the effective value of all these currents (phases R and r). THD for current of primary (R) phase and secondary (r) fase will be calculated. In this paper, the dimensional three-phase filter is set to eliminate the maximum harmonic component of current of the primary (R) phase on the 10 kV side of the transformer. The waveform, the corresponding harmonic content for the current and THD of primary (R) phase will be determined. Additional measures have been proposed to reduce the THD. Another parallel filter has been realized to eliminate the second by size harmonic components of primary (R) phase current. It will also compare THD for primary (R) phase as in the previous cases. For the total duration of the simulation, the used time is Tstop = 0.1 sec. All of the above simulations will be realized in the MATLAB/PSB program package and simulation models will be displayed.

scholarly journals Gap resonance and higher harmonics driven by focused transient wave groups

2017 ◽  
Vol 812 ◽  
pp. 905-939 ◽  
Author(s):  
W. Zhao ◽  
H. A. Wolgamot ◽  
P. H. Taylor ◽  
R. Eatock Taylor
Keyword(s):  
Incident Wave ◽  
Second Harmonic ◽  
Harmonic Component ◽  
Transient Wave ◽  
Sea State ◽  
Wave Groups ◽  
Wave Basin ◽  
Higher Harmonic ◽  
Harmonic Components ◽  
Quadratic Coupling

The first and higher harmonic components of the resonant fluid response in the gap between two identical fixed rectangular boxes are experimentally investigated in a wave basin. Gap response is excited by transient wave groups (being based on scaled versions of the autocorrelation function of sea-state spectra, representing NewWaves, the average shape of large waves in a sea state). Several different wave groups with different maximum surface elevations, spectral peak frequencies and bandwidths are used, while the bilge shape of the boxes and approach angle of the waves are also varied. Unlike a simple regular wave, it is complicated to separate the harmonic components for a transient wave group due to nonlinear wave–wave and wave–structure interactions. A four-phase combination methodology is used to separate the first four harmonic components, and this also allows higher harmonic components to be isolated with simple digital frequency filtering. Harmonic components up to 14th order in the incident wave amplitude have been extracted. It is shown that for an incident group with appropriate frequency content, the linear gap response may be substantially smaller than the second harmonic component, which is strongly driven via quadratic coupling of the linear terms from the incident wave and occurs in the gap resonant modes. Double frequency excitation may have important practical implications for offshore operations. Fourth and zeroth (long-wave) harmonics in the gap are further driven via quadratic coupling of the second harmonic itself. Linear damping coefficients for the first few modes of the gap resonant response are derived from measured time series using a numerical fit and shown to be higher than those from linear diffraction calculations.

Effect of Higher-Harmonic Deflection Components on the Creep Buckling of Columns

1957 ◽  
Vol 8 (3) ◽  
pp. 215-225 ◽  
Author(s):  
Sharad A. Patel ◽  
Joseph Kempner
Keyword(s):  
Power Function ◽  
Second Harmonic ◽  
Harmonic Component ◽  
Initial Amplitude ◽  
Creep Properties ◽  
Third Harmonic ◽  
Creep Buckling ◽  
Higher Harmonic ◽  
Harmonic Components ◽  
Simple Power Function

SummaryThe influence of higher-harmonic deflection components on the creep-buckling characteristics of an idealised H-section column is investigated. The creep properties of the material of the column are defined by a simple power-function creep law. The results show that higher-harmonic deflection components reduce the column lifetime significantly only when their initial amplitudes, as well as the initial amplitude of the first harmonic component, are very large. Furthermore, it is shown that second-harmonic components have a much smaller effect on the column behaviour than do third-harmonic components.

Study on Electrical Materials with the Circulation Control of STATCOM Based on MMC

2013 ◽  
Vol 327 ◽  
pp. 346-349 ◽  
Author(s):  
Yan Xie ◽  
Su Fen Li ◽  
Zhe Mao
Keyword(s):  
Power Level ◽  
Working Mechanism ◽  
Loop Control ◽  
Three Phase ◽  
In Series ◽  
Multi Level ◽  
Higher Harmonic ◽  
Harmonic Components ◽  
Electrical Materials ◽  
Level Converter

This paper introduced a new modular multi-level converter (MMC), which could enhance the voltage and power level by sub-converter modules in series and was easy to extend to any level of output. Its structure and working mechanism were described. By analyzing the higher harmonic components circulation generated by the inconsistencies in the three-phase upper and lower arm voltage, a loop control strategy is proposed for the suppression of the circulation in the arms of the M-STATCOM. Simulation results verify the effect of the controller.

Transient Analysis and Modelling of 2nd- and 4th-Order LCLC Filter under Non-Symmetrical Control

1970 ◽  
Vol 111 (5) ◽  
pp. 89-94 ◽  
Author(s):  
B. Dobrucky ◽  
M. Benova ◽  
S. Kascak
Keyword(s):  
Transient Analysis ◽  
Harmonic Distortion ◽  
Harmonic Component ◽  
Switching Frequency ◽  
Sinusoidal Voltage ◽  
Higher Harmonic ◽  
Simulation Results ◽  
Harmonic Components ◽  
Lc Filter

The paper shows how it is possible to obtain the harmonic sinusoidal voltage on the load side at non-harmonic periodical supplying from the converters. It can be used either LCLC resonant filter for frequency of fundamental harmonic component, or LC filter tuned for switching frequency. Both filters have to remove higher harmonic components from the supplying voltage to reach the harmonic distortion roughly 5 %. The paper deals mainly with analysis and modelling of 4th order LCLC filter (of the first type) under non-symmetrical supply and with comparing to the other types of filtering. Simulation results as well as experimental verification confirm good quality of output quantities of the filter. Ill. 19, bibl. 10 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.111.5.364

Stabilization of the Speed of the Hydraulic Motor Through Throttle Compensation for Volume Losses

2020 ◽  
Vol 26 (3) ◽  
pp. 126-130
Author(s):  
Krasimir Kalev
Keyword(s):  
Flow Rate ◽  
Hydraulic Drive ◽  
Pressure Change ◽  
Operating Conditions ◽  
Drive System ◽  
Inlet Pressure ◽  
Schematic Diagram ◽  
Hydraulic Characteristics ◽  
Hydraulic Motor ◽  
Flow Through

AbstractA schematic diagram of a hydraulic drive system is provided to stabilize the speed of the working body by compensating for volumetric losses in the hydraulic motor. The diagram shows the inclusion of an originally developed self-adjusting choke whose flow rate in the inlet pressure change range tends to reverse - with increasing pressure the flow through it decreases. Dependent on the hydraulic characteristics of the hydraulic motor and the specific operating conditions.

Study of the operation of an artificial neural network that works in the electric network in order to prevent emergency conditions.

2020 ◽  
Vol 14 (1) ◽  
pp. 48-54
Author(s):  
D. Ostrenko ◽  
Keyword(s):  
Neural Networks ◽  
Learning Algorithm ◽  
Electricity Consumption ◽  
Electrical Energy ◽  
Energy System ◽  
Electrical Networks ◽  
Electric Networks ◽  
Electric Network ◽  
Time Dynamics ◽  
Emergency Situations

Emergency modes in electrical networks, arising for various reasons, lead to a break in the transmission of electrical energy on the way from the generating facility to the consumer. In most cases, such time breaks are unacceptable (the degree depends on the class of the consumer). Therefore, an effective solution is to both deal with the consequences, use emergency input of the reserve, and prevent these emergency situations by predicting events in the electric network. After analyzing the source [1], it was concluded that there are several methods for performing the forecast of emergency situations in electric networks. It can be: technical analysis, operational data processing (or online analytical processing), nonlinear regression methods. However, it is neural networks that have received the greatest application for solving these tasks. In this paper, we analyze existing neural networks used to predict processes in electrical systems, analyze the learning algorithm, and propose a new method for using neural networks to predict in electrical networks. Prognostication in electrical engineering plays a key role in shaping the balance of electricity in the grid, influencing the choice of mode parameters and estimated electrical loads. The balance of generation of electricity is the basis of technological stability of the energy system, its violation affects the quality of electricity (there are frequency and voltage jumps in the network), which reduces the efficiency of the equipment. Also, the correct forecast allows to ensure the optimal load distribution between the objects of the grid. According to the experience of [2], different methods are usually used for forecasting electricity consumption and building customer profiles, usually based on the analysis of the time dynamics of electricity consumption and its factors, the identification of statistical relationships between features and the construction of models.

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