scholarly journals Influence of Lightning Current Model on Simulations of Overvoltages in High Voltage Overhead Transmission Systems

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 296 ◽  
Author(s):  
Jakub Furgał
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Transmission Lines ◽  
Current Model ◽  
Electrical Power ◽  
Electrical Networks ◽  
Electrical Power Systems ◽  
Transmission Systems ◽  
Lightning Current ◽  
High Voltage Transmission

The analysis of lightning overvoltages generated in electrical power systems has a great meaning for the designers and exploitation engineers because it creates bases for the optimization of construction overhead transmission lines and high voltage substations, reducing costs and increasing reliability of the transmission and distribution of electrical energy. Lightning overvoltages generated in electrical power systems with overhead transmission lines are a result of complex, nonlinear, and surge phenomena occurring in the structure of line towers and electrical substation when the lightning current is flowing through them. Methods of overvoltage stress analysis are intensely developed, and one of the directions is working out models of high voltage electrical devices and phenomena in electrical networks, which influence the shape and values of overvoltage risks. The model of lightning current has a significant influence on the courses of overvoltages in high voltage transmission systems. The paper is focused on the analysis of the influence of the model of lightning current making use of simulations of the shape, and maximal values of overvoltages generated in high voltage transmission systems during a direct lightning strike to the overhead lines. Two models of lightning current used in simulations with the Electromagnetic Transients Program/Alternative Transient Program (EMTP/ATP) were analyzed, i.e., the Heidler model and CIGRE (Conseil International des Grands Réseaux Électriques) model. The EMTP/ATP computer program is very often used in simulations of overvoltages in electrical networks. Unfortunately, the users get no information on the criterion to be used when selecting the model of lightning current used in the simulations. The analysis presented in the paper gives practical knowledge about the effect of the use of a particular kind of lightning current model on the results of simulations of lightning overvoltage propagation in electrical networks, overvoltage protection, as well as on theoretical and practical aspects of the insulation coordination in high voltage transmission systems.

Lightning Protection of Substations and the Effects of the Frequency-Dependent Surge Impedance of Transformers

2013 ◽  
pp. 398-437
Author(s):  
Rafal Tarko ◽  
Wieslaw Nowak
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Power Transmission ◽  
Electrical Power ◽  
Computer Calculation ◽  
Electrical Power Systems ◽  
Surge Arresters ◽  
Phase Conductors ◽  
Extra High Voltage ◽  
Economic Nature

The reliability of electrical power transmission and distribution depends upon the progress in the insulation coordination, which results both from the improvement of overvoltage protection methods and new constructions of electrical power devices, and from the development of the surge exposures identification, affecting the insulating system. Owing to the technical, exploitation, and economic nature, the overvoltage risk in high and extra high voltage electrical power systems has been rarely investigated, and therefore the theoretical methods of analysis are intensely developed. This especially applies to lightning overvoltages, which are analyzed using mathematical modeling and computer calculation techniques. The chapter is dedicated to the problems of voltage transients generated by lightning overvoltages in high and extra high voltage electrical power systems. Such models of electrical power lines and substations in the conditions of lightning overvoltages enable the analysis of surge risks, being a result of direct lightning strokes to the tower, ground, and phase conductors. Those models also account for the impulse electric strength of the external insulation. On the basis of mathematical models, the results of numerical simulation of overvoltage risk in selected electrical power systems have been presented. Those examples also cover optimization of the surge arresters location in electrical power substations.

scholarly journals Using waves to generate electricity

2010 ◽  
pp. 10-12
Author(s):  
Anne Blavette
Keyword(s):  
Power Systems ◽  
Wave Energy ◽  
Energy Supply ◽  
Fossil Fuel ◽  
Electrical Power ◽  
Modern Society ◽  
Well Being ◽  
Electrical Networks ◽  
Electrical Power Systems ◽  
Sea State

In less than a century, electricity has become the cornerstone of our modern society. Thanks to it, living conditions have changed more dramatically in 50 years than in two centuries. However, whereas electricity has provided well-being to billions of people over these past few decades, its ever-growing consumption is more and more threatening us. Climate change, fossil fuel depletion, and security of energy supply are crucial issues to be addressed for our “energy society” to be sustainable. Renewables are considered as a major part of the solution. This article deals with the issues related to integrating wave energy into electrical power systems. The major problem associated with wave energy is its variability. Variability can be observed at several time scales: from the range of seconds (wave-to-wave), to minutes (sea-state to sea-state), to days or months (seasonal variations). However, if wave energy is to be used for generating electricity, electrical networks ...

scholarly journals Steady state stability in electrical power systems considering operation limits in generators, transformers and transmission lines

2021 ◽  
Vol 18 (2) ◽  
Author(s):  
Fredy Estuardo Tamayo Guzmán ◽  
Carlos Andrés Barrera-Singaña
Keyword(s):  
Steady State ◽  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Electrical Power ◽  
Operating Conditions ◽  
Electrical Power Systems ◽  
Capacity Curves ◽  
Remedial Actions ◽  
Steady State Stability

Electrical power systems are exposed to several events that can cause unstable operation scenarios. This is due to improper operation of certain components. If an event occurs, the system must be designed to overcome that contingency, thus remaining in a permanent condition that must be evaluated in order to monitor and prevent a possible collapse of the system. An evaluation of steady state stability is proposed at this work based on the capacity curves of generators, transformers and transmission lines. These remarked curves provide information on the operation point of these elements, thus allowing the application of remedial actions. PowerFactory and Matlab are used to carry out the tool for monitoring the operation points after a contingency. The effectiveness of the developed tool is validated at the IEEE 39-bus power system model, where results shows that the functionalaty for different contingencies based on the operating conditions when the components of the power system are varied, cosnquently, the tool identifies cases that require actions at the operational level.

scholarly journals Effect of High Voltage Impulses on Surface Discharge at the Oil-Paper Interface

2018 ◽  
Author(s):  
R Clemence Kizza ◽  
M Ghaffarian Niasar ◽  
R Nikjoo ◽  
X Wang ◽  
H Edin
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Electrical Power ◽  
Test Sample ◽  
Surface Discharge ◽  
Electrical Power Systems ◽  
Lightning Strikes ◽  
Complete Breakdown ◽  
Voltage Transients ◽  
Discharge Patterns

<p>High voltage transients in electrical power systems are mainly caused by lightning strikes and switching operations. The high voltage transients above the basic insulation level (BIL) would degrade the electrical insulation of the equipment.<br />In this work, the effect of high voltage impulses on the trend of the surface discharge at the oil-paper interface was investigated. The partial discharge patterns were recorded by the Insulation Condition Monitoring (ICM) system. The HV impulses were generated by a standard 1.2/50 μs HV impulse generator. The measurement results presented in this paper seem to show that surface<br />discharge would cause complete breakdown (continuous flashovers) at the oil-paper interface much faster when the test sample is first aged by HV impulses compared<br />to when it is unaged.</p>

Investigation of Harmonic Current Aggregation in the TBE/Eletronorte Transmission System

2020 ◽  
Author(s):  
Maise N. S. da Silva ◽  
Rafael S. Salles ◽  
Alexandre Degan ◽  
Carlos A. Duque ◽  
Paulo F. Ribeiro
Keyword(s):  
Power Systems ◽  
Electrical Power ◽  
Transmission System ◽  
Phase System ◽  
Electrical Networks ◽  
Electrical Power Systems ◽  
Estimation Errors ◽  
Planning Stage ◽  
Harmonic Currents ◽  
Wide Range

Harmonic distortions are not new problems in electrical power systems. However, electrical networks have undergone several changes in recent decades, such as the wide range of electronic devices (converters, control devices, etc.), and those equipment produce emission of harmonic currents. The investigation of the contribution of several sources of harmonics in power systems is essential, considering that it is a problem of power quality that cannot be neglected. Thispaper aims to investigate the aggregation of harmonic currents in a 230kV TBE/Eletronorte system. For this, the transmission system was modeled using MATLAB/Simulink software with the typical values provided by TBE. A vectorial analysis was performed for the three-phase system and a sum analyzes of harmonics from different sources on Phase A, to estimate the influence of those current sources on Castanhal and Guama buses, when a harmonic spectrumis present on Vila do Conde and Utinga buses. In both analyzes, a phase angle spectrum of 10 and 20 degrees was applied in the harmonic source of Utinga. The summation analyzes proved to be useful because it can estimate values that harmonic currents can assume, for different conditions, and can be very useful in the planning stage to avoid estimation errors.

scholarly journals PARAMETRIC OPTIMIZATION OF OPERATING MODES OF BULK ELECTRICAL NETWORKS BY CRITERIA ACTIVE POWER LOSSES

2021 ◽  
Vol 2021 (59) ◽  
pp. 72-80
Author(s):  
V.V. Kuchanskyy ◽  
◽  
D.O. Malakhatka ◽  
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Transmission Lines ◽  
Reactive Power ◽  
Total Power ◽  
Electrical Networks ◽  
Power Losses ◽  
Operating Modes ◽  
Active Power Losses ◽  
Shunt Reactors

It is shown that the use of controlled shunt reactors enables, based on ultra-high voltage transmission lines, to create a controlled generation of new generation FACTS types that meet the requirements of modern power systems and combinations. Typical modes of operation of the high-voltage power line with installed controlled shunt reactors are analyzed. The efficiency of the use of controlled shunt reactors as measures of transverse compensation in ultrahigh voltage transmission lines is shown. The article shows that due to a smooth change in the consumption of excess reactive power of the transmission line, the normalization of the voltage values is achieved, and, accordingly, the total power losses are reduced. Ref. 9, fig. 3, tables 3.

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”.

scholarly journals Solar-Based DG Allocation Using Harris Hawks Optimization While Considering Practical Aspects

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5206
Author(s):  
Suprava Chakraborty ◽  
Sumit Verma ◽  
Aprajita Salgotra ◽  
Rajvikram Madurai Elavarasan ◽  
Devaraj Elangovan ◽  
...  
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Distribution Systems ◽  
Electrical Power ◽  
Electrical Networks ◽  
Power Networks ◽  
Effective Manner ◽  
Voltage Deviation ◽  
Overall Performance ◽  
Increasing Demand

The restructuring of power systems and the ever-increasing demand for electricity have given rise to congestion in power networks. The use of distributed generators (DGs) may play a significant role in tackling such issues. DGs may be integrated with electrical power networks to regulate the drift of power in the transmission lines, thereby increasing the power transfer capabilities of lines and improving the overall performance of electrical networks. In this article, an effective method based on the Harris hawks optimization (HHO) algorithm is used to select the optimum capacity, number, and site of solar-based DGs to reduce real power losses and voltage deviation. The proposed HHO has been tested with a complex benchmark function then applied to the IEEE 33 and IEEE 69 bus radial distribution systems. The single and multiple solar-based DGs are optimized for the optimum size and site with a unity power factor. It is observed that the overall performance of the systems is enhanced when additional DGs are installed. Moreover, considering the stochastic and sporadic nature of solar irradiance, the practical size of DG has been suggested based on analysis that may be adopted while designing the actual photovoltaic (PV) plant for usage. The obtained simulation outcomes are compared with the latest state-of-the-art literature and suggest that the proposed HHO is capable of processing complex high dimensional benchmark functions and has capability to handle problems pertaining to electrical distribution in an effective manner.

scholarly journals Understanding Reactive Power and Its Importance in Power Systems

2020 ◽  
Vol 9 (2) ◽  
pp. 880-883
Keyword(s):  
Magnetic Field ◽  
Power Systems ◽  
Transmission Lines ◽  
Reactive Power ◽  
Electrical Power ◽  
Electrical Machines ◽  
Voltage Profile ◽  
Electrical Power Systems

The main intent and purpose of this paper is to flaunt the rudimentary and homespun idea of reactive power on electrical power systems. Electrical machines such as motors and generators require reactive power for the production of magnetic field. Transformers and transmission lines too obligatory reactive power while they bring up with resistance and inductance contend with the flow of current. The Voltage profile must be uplifted to push this power through line inductance. Suitable reactive power when not used can cause contemplative blackouts.

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