scholarly journals Comparative Analysis of High-Voltage Power Line Models for Determining Short-Circuit Currents in Towers Earthing Systems

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4729
Author(s):  
Rafał Tarko ◽  
Jakub Gajdzica ◽  
Wiesław Nowak ◽  
Waldemar Szpyra
Keyword(s):  
High Voltage ◽  
Current Distribution ◽  
Single Phase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Power Line ◽  
Power Lines ◽  
Distribution Analysis ◽  
Short Circuits ◽  
Short Circuit Currents

The article deals with the problems of single-phase short-circuit current distribution in overhead power lines. Short-circuit disturbances cause many negative phenomena in power networks. Since experimental studies of short-circuits in real networks are practically impossible to perform, these effects can be evaluated only theoretically, based on short-circuit current calculations with the use of appropriate mathematical models. Although short-circuit modeling is considered to be one of the simplest power system calculations, the exact mathematical description of the phenomena occurring at short-circuits is complex. Simplified normative methods are often used for short-circuit current calculations; however, this does not give ground for a thorough analysis of short-circuit current distribution in power lines. The distributions are analyzed using power line models with different degrees of complexity in line with the assumptions made for a given model. The paper presents the problem of current distribution analysis in high-voltage overhead lines for single-phase faults to the tower structures. Simulation studies were conducted on the models developed for the calculation of short-circuit currents in the high-voltage power line earthing. The objective of the analysis was to assess the validity of simplification assumptions followed by practical recommendations on the applicability of the models.

scholarly journals Frequency and time fault diagnosis methods of power transformers

2018 ◽  
Vol 18 (4) ◽  
pp. 162-167 ◽  
Author(s):  
Miroslav Gutten ◽  
Daniel Korenciak ◽  
Matej Kucera ◽  
Richard Janura ◽  
Adam Glowacz ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
High Voltage ◽  
Impact Test ◽  
Power Transformer ◽  
Short Circuit ◽  
Small Deformation ◽  
Short Circuit Current ◽  
Diagnostic Methods ◽  
Response Analysis ◽  
Short Circuit Currents

Abstract The authors describe experimental and theoretical analyses of faults of power transformer winding. Faults were caused by mechanical effect of short-circuit currents. Measurements of transformer were carried out in high-voltage laboratory. Frequency and time diagnostic methods (method SFRA - Sweep Frequency Response Analysis, impact test) were used for the analyses. Coils of transformer windings were diagnosed by means of the SFRA method and the time impact test. The analyzed methods had a significant sensitivity to a relatively small deformation of coil. In the analysis a new technique for analyzing the effects of short-circuit currents is introduced. This technique is developed for high-voltage transformers (different types of power). The proposed analyses show that it is necessary to analyze the value of short-circuit current. Short-circuit current represents a danger for the operation of the power transformer. The proposed approach can be used for other types of transformers. Moreover, the presented techniques have a potential application for fault diagnosis of electrical equipment such as: transformers and electrical machines.

Investigation of dependences of selectivity of devices of protection against the value of short circuit currents in electrical networks up to 1000 V

2021 ◽  
pp. 98-100
Author(s):  
I. Radko ◽  
◽  
V. Nalivayko ◽  
O. Okushko ◽  
I. Bolbot ◽  
...  
Keyword(s):  
Single Phase ◽  
Modular Design ◽  
Short Circuit ◽  
Electrical Network ◽  
Electrical Networks ◽  
Circuit Breakers ◽  
New Energy ◽  
Short Circuits ◽  
Pole Scheme ◽  
Short Circuit Currents

According to PUE-2017, each group line must be protected against short circuits. Instant disconnection (cut-off) of the line in the event of short circuits provides an electromagnetic release of the circuit breaker. Reliable tripping is possible if the current of a single-phase short circuit is greater than the instantaneous tripping current. Today on the market are widely available circuit breakers with characteristics "B", "C" and "D", which are characterized by different multiplicities of the cut-off current of the electromagnetic release. Some European companies produce circuit breakers with other characteristics, which greatly expands the possibilities protection of electrical equipment. The difficulty in organizing the selectivity of protection is that the circuit breakers of modular design when switching off short circuits are characterized by the same switching time (not more than 0.05 s). The purpose of the research is to find ways to organize the selectivity of protection in electrical networks with voltage up to 1000 V using reliable values of short-circuit currents. In networks with a voltage of up to 1000 V, the current of a single-phase short circuit can be calculated fairly accurately if the exact values of all sections of the electrical network are known. In practice, it is not always possible to obtain reliable data on the numerical characteristics of the 0.4 kV network to which a new energy facility is connected. Therefore, it is proposed to consider part of the network as an active quadrupole, the characteristics of which are obtained by measurements at the point of connection. For further calculations it is necessary to know the voltage at the clamps of the four-pole scheme and the internal impedance. Based on the theory of four-pole scheme, you can get the original data for calculations without calculating the internal parameters of four-poles scheme. Thus, it is proposed to use a hybrid method for estimating the magnitude of probable short-circuit currents in electrical networks up to 1000 V when designing new energy facilities. Credible values of short-circuit currents will allow to organize selective protection of electric networks.

scholarly journals Analysis of influence of external atmospheric factors on the accuracy of fault location on overhead power lines

2020 ◽  
Vol 178 ◽  
pp. 01057
Author(s):  
Olga Ahmedova ◽  
Anatoliy Soshinov ◽  
Natalia Shevchenko
Keyword(s):  
Fault Location ◽  
Short Circuit ◽  
Power Line ◽  
Power Lines ◽  
Electrical Grids ◽  
Short Circuits ◽  
Atmospheric Factors ◽  
Overhead Power Lines ◽  
Overhead Power Line ◽  
Emergency Mode

Devices of fault location are widespread in electrical grids. In overhead power lines of voltages of 10 kV and higher, such devices are based on measurements of parameters in emergency mode. These devices can be divided into two main groups: designed to determine fault location of short circuits and of ground short circuit. In both cases, when detecting fault location, analyzed are not only the current and voltage parameters at the accident time, but also the parameters of overhead power line. When analyzing equivalent circuits of power lines, approximate tabular values of direct and quadrature parameters are used. It was revealed, that the line parameters are significantly affected by external atmospheric factors: ambient temperature, soil moisture, wind strength and direction, ice formation, etc. To accurately determine the fault location, it is necessary to evaluate the influence of these factors on the linear parameters of the overhead line. The paper presents analysis of the influence of changes in atmospheric factors on parameters of overhead power line. A methodology for calculating the operation setpoints of the device for fault location in power line is given.

scholarly journals Study and identification of short-circuit currents at the complex distribution network SIDER EL Hadjar (ex ArceloMittal-Algerie)

2018 ◽  
Vol 8 (1) ◽  
pp. 24-31
Author(s):  
Benhamida Hakim ◽  
Mesbah Tarek
Keyword(s):  
Power Supply System ◽  
Short Circuit ◽  
Distribution Network ◽  
Short Circuit Current ◽  
Supply System ◽  
Electricity Distribution ◽  
Short Circuits ◽  
Short Circuit Currents ◽  
Complex Distribution ◽  
Peak Value

Because of an upcoming modernisation of the electricity distribution network in the SIDER EL HADJAR steel complex, a new calculation of the short-circuit current must be taken into account. The objectives are to determine the precise values of the currents of maximum and minimum fault by each start 225 kV, 63 kV and 15 kV of the distribution network to ensure the reliability of the existing system, and to validate the sizing of the 63 kV bus bar follows the increase of the load of the transformer station P4 by replacing the 70 MVA transformer with a 120 MVA transformer and comparing the results to the old computation. The calculation of short-circuit currents is a key step in qualifying the equipment to withstand the thermal and electromagnetic effects. So, to appreciate the reliability of numerical computation of the currents of short circuits requires modelling and simulations with software NEPLAN V5. Keywords: Initial short-circuit current, power supply system (SIDER EL HADJAR), IEC 60909-0, peak value of short-circuit current, NEPLA software.    

scholarly journals The influence of changing resistance on the determination accuracy of short circuits in power lines

2021 ◽  
Vol 288 ◽  
pp. 01091
Author(s):  
Serdar Nazarov ◽  
Gurbangulych Kelov ◽  
Berdimyrat Gochyev
Keyword(s):  
Single Phase ◽  
Short Circuit ◽  
Stable State ◽  
Short Circuit Current ◽  
Scientific Work ◽  
Electric Power System ◽  
Electrical Networks ◽  
Zero Sequence ◽  
Short Circuits ◽  
Maintenance Personnel

In high-voltage electrical networks, the occurrence of short circuits leads to forced interruptions in the power supply of large consumers and disruptions in intersystem communications. More than 65% of all types of occurring short circuits are single-phase short circuits [1]. In a single-phase short circuits (SPSC), a change in the zero sequence resistance (ZSR) especially significantly affects the inaccuracy in detection of damage sites (DDS). When choosing DDS methods, preference is given to remote methods according to the parameters of the emergency conditions (PEC), which are recorded by special instruments or determined from the oscillograms of emergency conditions. The use of modern microprocessor-based relay protection and automation devices (RPA) [26] or emergency event recorders allow viewing the oscillograms of emergency events. In a branched 110 kV network with a complex configuration, the DDS accuracy is influenced by a change in the ZSR. Averaging of specific parameters often leads to erroneous results. The choice of one value from the oscillograms puts the maintenance personnel in difficulty. In the scientific work, the influence of changes in the ZSR on the accuracy of the DDS is considered. The changes in the ZSR are influenced by the position of the on-load voltage regulator (OLTC) switches of transformers with a grounded neutral. In the work, for a more accurate record of the specific parameters of the network, a calculation program has been compiled, which allows making changes in the calculated specific parameters of the network. To determine the short-circuit current from the oscillograms, it is proposed to determine the stable state of accidents in which the current value will be approximately the same. The analysis of the oscillograms of SPSC in 110-220 kV networks in the southern part of the electric power system of Turkmenistan has been carried out.

scholarly journals Study and identification of short-circuit currents at the Complex Distribution Network SIDER-EL Hadjar (ex ArceloMittal-Algerie)

2018 ◽  
Vol 8 (2) ◽  
pp. 79-86
Author(s):  
Benhamida Hakim ◽  
Mesbah Tarek
Keyword(s):  
Numerical Computation ◽  
Short Circuit ◽  
Distribution Network ◽  
Short Circuit Current ◽  
The Other ◽  
Electricity Distribution ◽  
Modeling And Simulations ◽  
Short Circuits ◽  
Short Circuit Currents ◽  
Complex Distribution

Because of an upcoming the modernization of the electricity distribution network in the SIDER EL-HADJAR steel complex, a new calculation of the short-circuit current must be taken into account. The objectives pursued in this article, is to determine the precise values of the currents of maximum and minimum fault by each start 225kV, 63kV and 15kV of the distribution network to ensure the reliability of the existing system, on the other hand is to validate the sizing of the 63kV bus bar follows the increase of the load of the transformer station P4 by replacing the 70MVA transformer with a 120MVA transformer and comparing the results to the old computation. The calculation of short-circuit currents is a key step in qualifying the equipment to withstand the thermal and electromagnetic effects. So it was question of appreciating the reliability of numerical computation of the currents of short-circuits which requires modeling and simulations with software NEPLAN V5.

Impacts of UHV on Short Circuit Currents in China's Central 500kV Grid and Its Countermeasures

2014 ◽  
Vol 960-961 ◽  
pp. 891-895
Author(s):  
Xu Zheng ◽  
Jiang Hong Wang ◽  
Mei Li ◽  
Shuang Zhao ◽  
Bu Han Zhang ◽  
...  
Keyword(s):  
Power System ◽  
High Voltage ◽  
Sharp Increase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Central China ◽  
Fault Current ◽  
Access Scheme ◽  
Short Circuit Currents ◽  
Lower Voltage

Ultra-high voltage (UHV) projects are making power system growing lager and resulting in sharp increase of short circuit currents in some area especially in the vicinity of UHV access points. The paper presented the damage of short circuit current increases and common methods to limit fault current. Taking the construction and development of UHV grid in a province of central China as background, the over short circuit currents in 500kV Grid within UHV were showed and several countermeasures including choosing proper UHV access scheme, implementing UHV substation lower voltage bus partition running, installing reactors, optimizing power grid network based on UHV connection point were proposed and then verified by PSASP simulation. The results show those measures are useful to reduce the short circuit current to a reasonable level.

About the Selection of a Single-Phase Short-Circuit Current on Earth in the Network With Low-Ohm Resistive Grounding of the Neutral

2017 ◽  
pp. 34-41
Author(s):  
Andrei V. MAIOROV ◽  
◽  
Kirill A. OSINTSEV ◽  
Andrei V. SHUNTOV ◽  
◽  
...  
Keyword(s):  
Single Phase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Selection Of
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