Sheath Voltages and Currents in 230kV Oil-Filled Underground Power Cables

2015 ◽  
Vol 781 ◽  
pp. 276-279 ◽  
Author(s):  
Surasak Phanthurat ◽  
Apibal Pruksanubal
Keyword(s):  
Electric Shock ◽  
Heat Losses ◽  
Power Cables ◽  
Grounding System ◽  
Three Phase ◽  
Underground Power Cables

Three-phase underground power cables can induce voltages and currents in their recover sheaths. The induced voltages and currents in sheath are undesirable. They generate heat losses and reduce the cable ampacity. Moreover, the induced voltages can generate electric shock to the workers, who maintain the power cables. It is very important to predict the sheath voltages and currents, which depend on different parameters, such as the sheath grounding system, the geometry of the cables, the gap between them, etc. In this paper, the voltages and currents induced in sheath for different installation of underground power cables (trefoil and flat formation) are studied and presented. For each case study of installation, the results of sheath voltages and currents have been computed and compared. Finally, the case of cross bonding with increasing of cable spans can reduce the sheath voltage significantly.

scholarly journals A statistical method for stastical appraisal of the power cable conditions based on the TD and PD diagsnostics result

2019 ◽  
Vol 124 ◽  
pp. 02014
Author(s):  
T. Neier ◽  
J. Knauel ◽  
M. Bawart ◽  
D. Antipov ◽  
S. Kim
Keyword(s):  
Life Time ◽  
Distribution Networks ◽  
Power Cable ◽  
Practical Case ◽  
Power Cables ◽  
Remaining Life ◽  
Power Utilities ◽  
Underground Power Cables ◽  
Asset Managers

This study handles one of the key questions of network operators: How can the remaining life time of underground power cables be estimated? The answer to this question is explained by a new method of KEPCO Korea. When combining VLF Tan Delta (TD) and Partial Discharge (PD) diagnostic it is possible to identify and localize weak individual spots along a cable. After weak spots are cleared, the general aging condition of the cable can be evaluated and the Remaining Life Time can be estimated. The implementation of this approach in the KEPCO Distribution Networks is illustrated in a practical case study. A new tool for asset managers is available and it is expected that it will help to further develop the preventive maintenance approach by power utilities all around the world.

scholarly journals Induced sheath voltages in 110 kV power cables – case study

2015 ◽  
Vol 64 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Stanislaw Czapp ◽  
Krzysztof Dobrzynski ◽  
Jacek Klucznik ◽  
Zbigniew Lubosny
Keyword(s):  
Electric Shock ◽  
Single Point ◽  
Optimal Configuration ◽  
Power Cable ◽  
Power Cables ◽  
Local Power ◽  
Economic Aspects ◽  
Maximal Power ◽  
Cable System

Abstract This paper considers electric shock hazard due to induced sheath voltages in 110 kV power cables. The purpose of this paper is to find an optimal configuration of the power cable system, taking into account electric shock hazard and ability of the system to transfer maximal power. A computer simulations on a computer model of the local power system, comprising high voltage power cables, were carried out. This model enables to analyse various configurations of the metallic cable sheaths bonding and earthing (single-point bonding, both-ends bonding, cross-bonding) and their impact on induced voltages in the cable sheaths. The analysis presented in the paper shows, that it is possible to find an optimal configuration of the complicated power cable system, in terms of electric shock hazard, maximal power transfer as well as economic aspects.

scholarly journals Safety Issues Referred to Induced Sheath Voltages in High-Voltage Power Cables—Case Study

2020 ◽  
Vol 10 (19) ◽  
pp. 6706
Author(s):  
Stanislaw Czapp ◽  
Krzysztof Dobrzynski
Keyword(s):  
High Voltage ◽  
Electric Shock ◽  
Short Circuit ◽  
Single Point ◽  
Power Cable ◽  
Power Cables ◽  
Power Losses ◽  
Cable Line ◽  
Low Level

Load currents and short-circuit currents in high-voltage power cable lines are sources of the induced voltages in the power cables’ concentric metallic sheaths. When power cables operate with single-point bonding, which is the simplest bonding arrangement, these induced voltages may introduce an electric shock hazard or may lead to damage of the cables’ outer non-metallic sheaths at the unearthed end of the power cable line. To avoid these aforementioned hazards, both-ends bonding of metallic sheaths is implemented but, unfortunately, it leads to increased power losses in the power cable line, due to the currents circulating through the sheaths. A remedy for the circulating currents is cross bonding—the most advanced bonding solution. Each solution has advantages and disadvantages. In practice, the decision referred to its selection should be preceded by a wide analysis. This paper presents a case study of the induced sheath voltages in a specific 110 kV power cable line. This power cable line is a specific one, due to the relatively low level of transferred power, much lower than the one resulting from the current-carrying capacity of the cables. In such a line, the induced voltages in normal operating conditions are on a very low level. Thus, no electric shock hazard exists and for this reason, the simplest arrangement—single-point bonding—was initially recommended at the project stage. However, a more advanced computer-based investigation has shown that in the case of the short-circuit conditions, induced voltages for this arrangement are at an unacceptably high level and risk of the outer non-metallic sheaths damage occurs. Moreover, the induced voltages during short circuits are unacceptable in some sections of the cable line even for both-ends bonding and cross bonding. The computer simulations enable to propose a simple practical solution for limiting these voltages. Recommended configurations of this power cable line—from the point of view of the induced sheath voltages and power losses—are indicated.

The Thermooxidation and Resistance to Moulds Action of Some Polyethylene Sorts Used at Anticorrosive Insulation of the Underground Pipelines

2017 ◽  
Vol 54 (3) ◽  
pp. 447-452 ◽  
Author(s):  
Adriana Mariana Bors ◽  
Nicoleta Butoi ◽  
Alina Ruxandra Caramitu ◽  
Virgil Marinescu ◽  
Iosif Lingvay
Keyword(s):  
Heat Treatment ◽  
Thermal Analysis ◽  
Culture Media ◽  
Power Cables ◽  
Polymerization Degree ◽  
Crosslinking Degree ◽  
Underground Pipelines ◽  
Predominant Process ◽  
Underground Power Cables ◽  
Coupled Techniques

Polyethylene (PE) insulations have a wide applicability in the insulation of both underground pipelines and underground power cables. In this context, by coupled techniques of thermal analysis (TG/DTG+DTA) and microbiological determinations, have been studied thermooxidability and resistance to moulds action of some polyethylene sorts. Following the processing of the experimental data obtained by thermal analysis it was found that during the applied heat treatment (100 grd C), in the first approx. 380 h, there is a growth of LDPE (low density polyethylene) polymerization degree by elongation of the aliphatic chains, after which the predominant process consists in the structure crosslinking. For MDPE (mean density polyethylene) samples, during the thermal treatment applied, it was found that the crosslinking degree of polyethylene (PE) increased without significant molecular weight change (with all the related consequences of increasing the weight of the tertiary and quaternary carbon atoms in the molecule). Microbiological determinations have highlighted that the resistance to filamentous fungal action of LPDE is higher than that of the investigated MDPE. It was found that after heat treatment applied (1000 h and 100 oC), both at LDPE and at MDPE, decreases the resistance to moulds action is decreased. It has also been found that moulds action resistance is substantially decreased when inoculated culture media and PE samples are exposed to an alternative electric field of 50 Hz - 6 Vrms/cm.

scholarly journals Investigation and Improvement of Standard External Lightning Protection System: Industrial Case Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4118
Author(s):  
I Made Yulistya Negara ◽  
Daniar Fahmi ◽  
Dimas Anton Asfani ◽  
IGN Satriyadi Hernanda ◽  
Rendi Bagus Pratama ◽  
...  
Keyword(s):  
Petrochemical Industry ◽  
Protection System ◽  
Lightning Protection ◽  
Industrial Case Study ◽  
Grounding System ◽  
Electromagnetic Transient ◽  
Petrochemical Company ◽  
Program Software ◽  
Ground Potential

In this study, the lightning protection system and grounding system of one plant of the petrochemical industry were investigated, evaluated, and improved. The methods used in this study were rolling sphere and angle protection methods. The grounding system of the building under study was modeled and simulated using ATP/EMTP (Alternative Transient Program/Electromagnetic Transient Program) software. The results show that the external lightning protection system of the prilling tower studied does not adhere to IEC 62305 and IEC 1024-1-1 standards. Moreover, the grounding configuration of the DCS building was not appropriate for protecting sensitive equipment inside. Lightning causes an enormous potential difference between lightning ground rods in the grounding system. Additionally, disabling the existing surge protective device (SPD) causes an increase in the magnitude of Ground Potential Rise at the DCS building. Improvement of the lightning protection system of the prilling tower and DCS building on Plant 1 of this petrochemical company as well as some other recommendations for improvements are proposed. This paper also shows evidence that external lightning protection, internal lightning protection, and the grounding system need to be connected to make an exemplary lightning protection system.

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