scholarly journals Improving the voltage quality of Abu Hummus network in Egypt

2020 ◽  
Vol 10 (5) ◽  
pp. 4458 ◽  
Author(s):  
Ibrahim A. Nassar ◽  
Mohammed Sh. Seif ◽  
Mahmoud M. ElAttar
Keyword(s):  
Transmission Lines ◽  
Low Voltage ◽  
Digital Simulation ◽  
Main Idea ◽  
Load Flow ◽  
Operating Conditions ◽  
Electrical Network ◽  
Transmission Network ◽  
Voltage Quality

In this paper the performance of the electrical network of Egypt is studied by considering a small part on the network (Abu Hummus city). The transmission network of Abu Hummus city was created for 66 kV, 11 kV, and 0.4 kV in the digital simulation and electrical network calculation (DIgSILENT power factory software) to study the voltage profiles. The load flow operational analysis was performed to obtain the voltage magnitudes at every bus bar. The voltage magnitudes in 11 kV and 0.4 kV networks were 10% to 15% less than the nominal value due to overloading off the transmission lines and the voltage magnitudes in 66 kV was within permissible limits. By using automatic tap-changing transformer or Static VAR System, the main idea of this paper is to obtain the voltage profiles at every bus bar to improve the voltage quality of the networks, so as to achieve better voltage profiles on the low voltage side without much effect on high voltage side under various operating conditions.

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 Transmission Network Expansion Planning Considering Phase-Shifter Transformers

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Celso T. Miasaki ◽  
Edgar M. C. Franco ◽  
Ruben A. Romero
Keyword(s):  
Mathematical Model ◽  
Transmission Lines ◽  
Phase Shifter ◽  
Planning Process ◽  
Main Idea ◽  
Mixed Integer ◽  
Planning Problem ◽  
Transmission Network ◽  
Network Expansion ◽  
Expansion Planning

This paper presents a novel mathematical model for the transmission network expansion planning problem. Main idea is to consider phase-shifter (PS) transformers as a new element of the transmission system expansion together with other traditional components such as transmission lines and conventional transformers. In this way, PS are added in order to redistribute active power flows in the system and, consequently, to diminish the total investment costs due to new transmission lines. Proposed mathematical model presents the structure of a mixed-integer nonlinear programming (MINLP) problem and is based on the standard DC model. In this paper, there is also applied a specialized genetic algorithm aimed at optimizing the allocation of candidate components in the network. Results obtained from computational simulations carried out with IEEE-24 bus system show an outstanding performance of the proposed methodology and model, indicating the technical viability of using these nonconventional devices during the planning process.

Corona Detection System on Insulators via Acoustic Emissions

2012 ◽  
Vol 260-261 ◽  
pp. 379-384
Author(s):  
Marco Antônio Martins Rennó ◽  
Erik Leandro Bonaldi ◽  
Levy Ely Lacerda Oliveira ◽  
Jonas Guedes Borges Silva ◽  
Germano Lambert-Torres
Keyword(s):  
Climate Change ◽  
Quality Of Service ◽  
Transmission Lines ◽  
Detection System ◽  
Low Cost ◽  
Acoustic Emissions ◽  
Computer Programs ◽  
Operating Conditions ◽  
Operational Capacity

This paper presents a computational package and equipment with the purpose to detect corona problems of insulators in transmission lines. Low-cost equipment detects presence of corona, via acoustic emissions and stores them in a memory. These data are processed by computer programs. The applicability of this equipment is immediate for any transmission company, because the perfect understanding of the operational capacity of its lines in various operating conditions and climate change allows for a safer operation with improvement of quality of service provided.

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.

scholarly journals ANALYSIS OF FACTORS INFLUENCING THE INTENSITY OF TRANSFORMER OIL AGEING IN LONG-TERM OPERATION

2021 ◽  
pp. 3-9
Author(s):  
Serhii Ponomarenko
Keyword(s):  
Organic Acids ◽  
Analysis Of Variance ◽  
Low Voltage ◽  
Operating Time ◽  
Operating Conditions ◽  
Transformer Oil ◽  
Term Operation ◽  
Oxidative Reactions ◽  
Rate Of Increase

The results of the analysis of influence of operational factors and peculiarities of transformer design on intensity of oxidative reactions of transformer oils in the tanks of 110 kV high-voltage power transformers are presented. As a result of two-way analysis of variance it was found that with increasing operating time there is a statistically significant increase in the value of the organic acid content in the oil. At the same time the rate of increase in the organic acids content in the transformer oil, operated under different conditions, significantly differs, which indicates a significant influence of operating conditions on the intensity of oxidative reactions. The results of two-way analysis of variance also show that the effects of changes in factor levels are not additive, that is, the effect of a change in the level of influence of one factor leads to a change in the effect of the level of influence of another. In other words, the process of oil oxidation is cumulative and a certain level of organic acids in the oil can be achieved either over a longer period of operation, but with relatively 'light' operating conditions, or over a shorter period of time, but with more 'heavy' operating conditions. In order to determine the factors most affecting the intensity of oxidative reactions, an analysis of the quality of filled oil, operating time, the influence of the region, the influence of the type and nominal characteristics of transformers on 6 data sets with identical rates of oxidative reactions was carried out. The results of the analysis show that the intensity of oxidation reactions is strongly influenced by the operating time, the transformer loading factors, the consumer composition (region of Ukraine) as well as the type and quality of oils. At the same time, factors such as rated capacity, type of transformer, number of windings, and the value of rated voltage on the medium and low voltage windings do not influence the intensity of oxidation of oils. The results obtained allow the correction of the maximum permissible values of oil acidity, taking into account the factors affecting the intensity of oxidation of oils.

scholarly journals Voltage Profile Improvement of a Disturbed Electric Power System using UPFC Compensation

2020 ◽  
Vol 8 (5) ◽  
pp. 1888-1893
Keyword(s):  
Transmission Line ◽  
Electric Power ◽  
Transmission Lines ◽  
Load Flow ◽  
Electric Power System ◽  
Base Case ◽  
Transmission Network ◽  
Voltage Profile ◽  
Voltage Profile Improvement ◽  
Flow Study

The major objective of using flexible alternating current transmission systems (FACTS) devices in an interconnected electric power transmission network is to improve the parameters of the transmission line. This study presents the voltage profile improvement and power loss reduction of the Nigeria 330 kV transmission network using the unified power flow controller (UPFC) as an optimal FACTS device. The study utilized the power systems analysis toolbox (PSAT) 2.1.10 that is embedded in MATLAB 2017a to model the Nigeria 330 kV transmission network that consists of 9 generating stations, 31 buses and 42 transmission lines. The Newton Raphson load flow algorithm was used to carry out the load flow study using data obtained from the transmission company of Nigeria. Voltages less than 0.95pu (313.5kV) were assumed to be low voltage while those greater than 1.05pu (346.5kV) were assumed to be high voltage. A base case load flow study was carried out without the use of UPFC to determine weak buses. The outcome of the base case simulation without the use of the UPFC showed that seven buses were operating outside the lower operating limit. After compensation using the UPFC, the operating voltages at each of the buses were found to be within the stated limit. Findings from the study show that the weak buses occurred as a result of the long distances between the transmission lines and the generating stations. The transmission line losses were found to have been reduced from 71.66MW to 32.95MW and from 76.7MVAR to 41.89MVAR respectively.

scholarly journals The Influence of Voltage Quality on Asynchronous Motor Performance of EKG Excavator in Open Pit Mines – Vinacomin

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Xuan Cuong Ngo ◽  
Do NHU Y ◽  
Tran QUANG HIEU
Keyword(s):  
Asynchronous Motor ◽  
Simulation Software ◽  
Open Pit ◽  
Open Pit Mining ◽  
Electrical Network ◽  
Open Pit Mines ◽  
Voltage Quality ◽  
Electric Excavator ◽  
Nonsinusoidal Voltage

At present, in open-pit mining, the main and most important electrical load is the electric excavator, and currently using a variety of EKG excavators. 6kV electrical network in open pit mining has the characteristics such as long outgoing lines, use high-powered equipment, multiple branches, and increasing use of power electronics on the grid, this reduces the quality of the power supplied to the excavators EKG, resulting in an increase in power losses thereby greatly affecting the performance of the excavators. Previous studies on the quality of the power supplied to the excavator often only mentioned voltage deviations, in addition to this factor, the performance of the excavator is also greatly affected by nonsinusoidal voltage waveforms of the excavator power supply. This paper analyzes the influence of the nonsinusoidal of voltage on the power loss of electric motors used in EKG electric excavators in open pit mining based on the method of electromagnetic analysis and verification on simulation software.

Supply voltage quality in low voltage industrial networks of Estonia

2011 ◽  
Vol 18 (2) ◽  
pp. 102 ◽  
Author(s):  
T Vinnal ◽  
K Janson ◽  
J Järvik ◽  
H Kalda ◽  
T Sakkos
Keyword(s):  
Low Voltage ◽  
Supply Voltage ◽  
Industrial Networks ◽  
Voltage Quality

Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

Relationships between Population Dynamics and Operating Parameters in an Activated Sludge-Plant by Statistical Analysis

1992 ◽  
Vol 25 (4-5) ◽  
pp. 399-400 ◽  
Author(s):  
L. Cingolani ◽  
M. Cossignani ◽  
R. Miliani
Keyword(s):  
Population Dynamics ◽  
Statistical Analysis ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Statistical Analyses ◽  
Operating Parameters ◽  
Aerobic Treatment

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.

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