Determination of Electromagnetic Influence of 25 kV AC Electric Traction Network on 10 kV High-Voltage Overhead Line

Abstract Electrified railways include a system of cable and overhead lines. An analysis of the operation of alternating current (AC) electrified railways sections shows that the value of the induced voltage caused by the operation of the traction network can significantly exceed the permissible level on adjacent disconnected high-voltage overhead lines. As a consequence, this leads to serious injuries to operating personnel, including deaths, failure of electrical equipment. From this point of view, 1x25 kV 50 Hz AC railway system networks are considered the most dangerous. The electromagnetic influence of the traction network of a double-track section of an AC railway on an adjacent 10 kV high-voltage overhead line for power supply of automatic block signalling is investigated in the offered paper. Emergency cases of traction network operation are considered: short-circuit situation and forced state. The calculations of short-circuit currents in the influencing inter-substation zone, as well as estimation of the induced voltage on the wires of the 10 kV disconnected high-voltage overhead line for various schemes of grounding, have been performed. The investigations were carried out on models built using the ATP-EMTP program.

Download Full-text

Accounting power supply schemes for traction substations in the calculation of short circuits in the AC traction network

Vestnik of the Railway Research Institute ◽

10.21780/2223-9731-2019-78-1-10-18 ◽

2019 ◽

Vol 78 (1) ◽

pp. 10-18 ◽

Cited By ~ 3

Author(s):

Yu. I. Zharkov ◽

N. A. Popova ◽

E. P. Figurnov

Keyword(s):

High Voltage ◽

Power Supply ◽

Power Supply System ◽

Short Circuit ◽

Supply System ◽

Power Sources ◽

Traction Network ◽

Traction Substations ◽

External Power ◽

External Power Supply

When calculating short-circuit currents in the AC traction network, it is assumed that each of the traction substations receives power from uncoupled external power supply sources with known resistances. In some cases, especially when powering a group of traction substations from a high-voltage power line of a longitudinal power supply, the external power supply system affects not only the magnitude of short-circuit currents, but also their redistribution between adjacent traction substations of the interstation area where this circuit is considered. Such unrecorded redistribution can have a negative effect on short circuit protection. The article considers the equivalent circuit of the traction network, taking into account resistance of the external power supply system. Particular attention is paid to the fact that in replacement circuits of direct and negative sequence value of reduced resistance of one phase of a multiwinding transformer, calculated from the short circuit voltage, does not depend on the connection scheme of its windings. It is noted that in some cases it is difficult to obtain a complete scheme of an external power supply system. Considering that the short circuit in the traction network for the external power supply system is remote, it is proposed taking into account the reference network or traction substations as power sources, from which high-voltage transmission lines power the traction substations. Resistance of the supporting substations as power sources must takes into account connected equivalent power system.Such equivalenting should be carried out by known values of currents or short-circuit powers at the inputs of the reference substation or, if such information is not available, by the rated values of the switched-off currents or powers of the switches of high-voltage line connections.The following power schemes for traction substations are considered: each from its own supporting substation, which is part of an electrically uncoupled external power supply system; from the double-circuit high-voltage line of longitudinal power supply when it is powered from different supporting substations; from the supporting network substation, the traction substation receives power from two lines, and from this the traction substations receive power from two lines in a circle pattern.These three common cases cover all the most common power schemes for traction substations. For each of them formulas are given to determine the resulting equivalent resistance of the external power supply circuit, which should be taken into account in the replacement circuit of the traction network.

Download Full-text

EVALUASI SETTING RELAI JARAK (DISTANCE RELAY) PADA SALURAN UDARA TEGANGAN TINGGI (SUTT)150 kV ANTARA GARDU INDUK SIDERA-GARDU INDUK TIPO

Foristek ◽

10.54757/fs.v9i1.67 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Martho Pamula ◽

Sangbua Dinsol Pirade ◽

Yulius S. Pirade ◽

Nurhani Amin

Keyword(s):

Transmission Line ◽

High Voltage ◽

Power Plants ◽

Short Circuit ◽

Transmission Network ◽

Overhead Line ◽

Distance Relay ◽

On Line

Abstract-Overhead line high voltage (SUTT) or commonly called a transmission network or transmission line has very important role in the process of distribution of electrical from power plants to load centers continuously. However, overhead line is one component in the system which is often fault. To avoid damages and greater losses, it has used the distance which is as the primary protection in securing the transmission network or transmission line. In this research, it discussed about one phase-neutral short circuit that happens on line transmission connected to Sidera-Tipo substation by calculating the current fault andoperating time of distance relay using the software of ETAP (electric transientandanalysis program) 12.6.0.

Download Full-text

Analysis of the Torsional Stability of Split Phases

ENERGETIKA Proceedings of CIS higher education institutions and power engineering associations ◽

10.21122/1029-7448-2019-62-6-503-513 ◽

2019 ◽

Vol 62 (6) ◽

pp. 503-513

Author(s):

I. I. Sergey ◽

Y. G. Panamarenka ◽

Y. V. Potachits ◽

N. A. Yudina

Keyword(s):

High Voltage ◽

Climatic Factors ◽

Short Circuit ◽

Low Frequency ◽

Power Lines ◽

Structural Elements ◽

Stability Calculation ◽

Overhead Lines ◽

Torsional Stability ◽

Overhead Power Lines

The specificity of overhead power lines is associated with the fact that the length of conductors between the supporting structures can reach tens of thousands of meters. Wires and their components are exposed to climatic factors, viz. wind, rain, ice, snow. As compared to other structural elements, conductors are of the highest flexibility and lowest rigidity, and, therefore, they are the most sensitive elements to these effects. Since the early fifties of the XX century, the increase in energy consumption has caused the construction of high and ultra-high voltage overhead lines with split phases. For these types of conductors, new forms of oscillations have been noticed in the areas between the struts, the essence of which is torqueing the split phase. As a result, there is a violation of the torsional stability of the phase: collision of wires in the middle of sub-span and friction of wires of stranded conductor against each other, which leads to damaging conductors and, as a consequence, to disruption of power supply to consumers. Almost any overhead lines may be subjected to oscillations of wires in the span under the influence of wind. One of the types of such mechanical oscillations is galloping, i. e. low-frequency oscillations of wires with an amplitude reaching the value of the boom of wire sagging, and, taking into account the possibility of elongation of the wire, even exceeding it. Fluctuations in the galloping can cause significant mechanical forces and last long enough to lead to the destruction of structural elements of power lines, viz. wires, insulators, fittings and even pillars. Due to the large amplitude of oscillations, conductors of neighboring phases can approach each other at an unacceptable distance, resulting in a short circuit. The boundary value problem of the torsional stability calculation of the split phase with a given multiplicity of splitting has been set and solved. The critical lengths of the sub-spans at which the stable violation of torsional stability is most likely have been determined. A computer program has been developed, which can be used in the design of high-voltage lines with split phase.

Download Full-text

Feature Extraction Based on the Multiple Harmonic Analysis of 2-Dimensional Pattern of Partial Discharge

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.303-306.478 ◽

2013 ◽

Vol 303-306 ◽

pp. 478-481

Author(s):

Yu Long Gong ◽

Jin Xi Guo ◽

Hong Fu Guo

Keyword(s):

Harmonic Analysis ◽

High Voltage ◽

High Frequency ◽

Short Circuit ◽

Partial Discharge ◽

Characteristic Parameter ◽

Electrical Equipment ◽

Normal Operation ◽

Harmonic Components ◽

Insulation Breakdown

Partial discharge will cause deterioration of insulation of high-voltage electrical equipment, resulting in insulation breakdown and short circuit accident. In order to ensure the normal operation of the high-voltage equipment, it is necessary to detect partial discharge online. By using Ultra High Frequency (UHF) defection method, statistical 2-dimensional (2D) patterns of partial discharge are obtained. Extracting the envelopes of the 2D patterns, we do the harmonic analysis for patterns’ envelopes, and the harmonic components are used as a characteristic parameter for defect type’s recognition. The results show that the harmonic components can be used as characteristic parameter for defect types’ recognition. This method has the characteristics of strong real-time and simple operation.

Download Full-text

A model for calculating the temperature of aluminium particles ejected from overhead low-voltage lines owing to a short-circuit

International Journal of Wildland Fire ◽

10.1071/wf08128 ◽

2009 ◽

Vol 18 (6) ◽

pp. 722 ◽

Cited By ~ 6

Author(s):

E. G. Psarros ◽

A. D. Polykrati ◽

C. G. Karagiannopoulos ◽

P. D. Bourkas

Keyword(s):

Mathematical Model ◽

Molten Metal ◽

High Voltage ◽

Temperature Rise ◽

Low Voltage ◽

Short Circuit ◽

Weather Conditions ◽

Metal Particles ◽

Overhead Lines ◽

Protection Systems

Wildfires, which are uncontrolled fires spreading readily over vast areas, are usually the result of human negligence, arson or lightning. There are cases of fires close to electrical distribution lines for which the network has been blamed. In the present paper, the risk of a wildfire breaking out owing to the temperature of molten metal particles that are possibly created on bare conductors of low-voltage networks in short-circuit faults (unless they are interrupted by the protection systems) is examined. Thus, a mathematical model is proposed for the estimated temperature rise of those molten metal particles ejected from bare conductors of low-voltage overhead lines. Moreover, this model can be applied to medium- or high-voltage networks. The model takes into account the weather conditions and particles’ height above the ground. Further, an arithmetic example for an incandescent particle ejected from aluminium conductors of a low-voltage network is given. According to this example, there is no risk of dead leaves or wood catching fire owing to this particle.

Download Full-text

Mathematical Explanations of a Paradox Observed in a HVAC (High Voltage Alternating Current) Untransposed Overhead Line

Energies ◽

10.3390/en12040734 ◽

2019 ◽

Vol 12 (4) ◽

pp. 734

Author(s):

Adrian Pană ◽

Alexandru Băloi ◽

Florin Molnar-Matei

Keyword(s):

High Voltage ◽

Real Line ◽

Power Flow ◽

Alternating Current ◽

Operating Conditions ◽

Overhead Line ◽

The Real ◽

Overhead Lines ◽

Mathematical Explanations ◽

Load Conditions

The constructive asymmetry of the untransposed overhead lines of a high voltage alternating current is the cause of a great number of difficulties in their operation and modeling. In order to model the operating regimes of such lines, the symmetrical component method, based on constructive symmetry and thus the symmetry of the equivalent phase parameters, is inappropriate, which is why many research papers have been dedicated to either setting up improved modeling methods or to returning to phase coordinate modeling. This paper intends to justify a paradox found on some untransposed overhead lines of a high voltage alternating current during the no-load operating conditions by performing phase coordinate modeling. In such a situation, the transmission or distribution operators measured significant negative values for the active powers on one or two phases at the beginning of the lines. Considering the case of a real untransposed overhead line operating under no-load conditions, the paper starts from presenting the recorded electrical values. Then, the paper moves on to outlining the Carson’s simplified computing relations for calculating the series and shunt primitive equivalent parameters and Kron’s transformation relationships for calculating the phase equivalent parameters. After applying them to the real line, the calculation of the power flow for the no-load operating conditions, which is applied to an equivalent scheme of the line consisting of nine identical octopoles, is performed. Both the untransposed line and its transposed variant are studied here. The values of the electrical amounts obtained by the calculation for the untransposed line are basically similar to those obtained by measuring on the real line, which gives a mathematical confirmation of the so-called paradox. Its occurrence represents the effect of the asymmetry of the equivalent phase capacities, which causes a redistribution of the active powers between the phases of the network to which the overhead line operating in no-load conditions is connected.

Download Full-text

Investigation of the Influence of the Electromagnetic Field in the Vicinity of High Voltage Overhead Line

Materials Science Forum ◽

10.4028/www.scientific.net/msf.856.190 ◽

2016 ◽

Vol 856 ◽

pp. 190-195 ◽

Cited By ~ 2

Author(s):

Atanas Chervenkov ◽

Todorka Chervenkova

Keyword(s):

High Voltage ◽

Electromagnetic Compatibility ◽

Short Circuit ◽

Electrical Equipment ◽

Power Line ◽

Lightning Strike ◽

Magnetic Flux Density ◽

Fem Model ◽

Overhead Power Line ◽

Emergency Mode

The magnetic and electrical field in the vicinity of overhead power line for high voltage - 220 kV is investigated. FEM model is created. Simulations of normal and emergency mode of the power line are made. The electrical intensity at idle mode in some areas, close to overhead power line, creates a high voltage level for humans. It can create also disturbances in the electrical equipment and the vehicles. These surges violate electromagnetic compatibility. The magnetic induction at emergency mode – short circuit and lightning strike in the areas around the towers could give a disturbing reaction of humans, animals and sensitive electronic devices. One solution for decreasing of the magnetic flux density to acceptable values is offered.

Download Full-text

Induced electromagnetic field on underground metal pipelines running parallel to nearby high voltage AC power lines

E3S Web of Conferences ◽

10.1051/e3sconf/201910702004 ◽

2019 ◽

Vol 107 ◽

pp. 02004

Author(s):

Giovanni Dushimimana ◽

Patrobers Simiyu ◽

Vedaste Ndayishimiye ◽

Emile Niringiyimana ◽

Sefu Bikorimana

Keyword(s):

Electromagnetic Field ◽

High Voltage ◽

Short Circuit ◽

Power Lines ◽

Induced Voltage ◽

Steady State Condition ◽

Ac Power ◽

Safe Limits ◽

Adjacent Soil ◽

Gradient Control

High voltage AC (HVAC) power lines can induce significant amount of voltages on underground gas/oil metal pipelines in areas where they share similar Right of Way (RoW), the situation becoming serious particularly in case of fault conditions. Electromagnetic field generated by the HVAC power lines on these pipelines, generate unwanted voltages which present threats to the pipeline and its associated protective equipment such as cathodic systems. The aim of this research is to compute induced voltage on pipeline running parallel to HVAC power lines. The study was conducted using CDEGS software package and revealed that under steady state condition, results were in agreement with GB 6830-1986 standard. However, high currents are generated under single phase to ground short circuit rising the potential of adjacent soil including the underground pipeline beyond limits. Therefore, the gradient control wire mitigation technique is proposed to reduce these voltages to safe limits.

Download Full-text