Development of the Thermal Equivalent Circuit for Evaluating the Capacity of High Voltage Cables in Real Time

The authors of this paper justify the construction of the thermal equivalent circuit for a three-phase high voltage cable line that describes the transient thermal processes in the cross section of the line. According to the authors, the proposed scheme, if taken as a basis, allows to solve the task of evaluating the power capacity of high-voltage cable lines in real-time and predict heating of cables with the aim to prevent thermal degradation of the insulation.

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Development of Calculation Methodology of Thermal Equivalent Circuit’s Parameters for Predicting Temperature of High Voltage Cable Lines 110 - 500 kV

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.792.272 ◽

2015 ◽

Vol 792 ◽

pp. 272-279

Author(s):

Evgeny Zaytsev

Keyword(s):

Thermal Degradation ◽

Equivalent Circuit ◽

High Voltage ◽

Cable Line ◽

Calculation Methodology ◽

Equivalent Circuit Parameters ◽

Cable Lines

This paper is concerned with the development of techniques to the calculation of the thermal equivalent circuit parameters for the high-voltage cable line laid in the ground. The topology of the scheme was developed in author’s previous publication. This article discusses the parameters of the circuit which simulate the environment of the cable line. Calculation techniques of these parameters are described for cables laid in a plane and a trefoil pattern. The proposed scheme allows one to predict heating of cables on the day ahead in order to prevent thermal degradation of the insulation.

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Simulation study of 6–10 kV cable lines for transient processes calculation during earth faults

Vestnik IGEU ◽

10.17588/2072-2672.2021.5.030-040 ◽

2021 ◽

pp. 30-40

Author(s):

V.A. Shuin ◽

Yu.D. Kutumov ◽

N.V. Kuzmina ◽

T.Yu. Shadrikova

Keyword(s):

Frequency Dependence ◽

Single Phase ◽

Transient Processes ◽

Cable Line ◽

Frequency Dependent ◽

Cable Networks ◽

Ground Fault ◽

Three Phase ◽

Frequency Independent ◽

Cable Lines

As a rule, researchers do not consider the dependence of the inductance of cable lines on frequency in their scientific papers devoted to the calculation of transient processes during single phase-to-ground fault in 6–10 cable networks. In some cases, it can lead to significant errors in evaluation of current and voltage transient components parameters. Therefore, it is an urgent task to estimate defined errors and the scope of application of frequency-independent equivalent circuits and models of 6–10 kV cable lines during calculation and simulation of transient processes in case of single phase-to-ground fault. The authors applied PSCAD / EMTDC software to study the effect of the frequency dependence of the inductances of 6–10 kV cable lines on the calculation accuracy of transient processes during single phase-to-ground fault. It allows to simulate electric power systems models with the usage of both frequency-dependent and frequency-independent cable line models with round conductors only. To check the adequacy of the frequency-dependent three phase cable model developed in PSCAD software, the authors have used a frequency-dependent model of 6–10 kV three-phase cable with sector-shaped conductors designed in COMSOL Multiphysics software. The authors have developed an approach to develop of 610 kV cable lines models with frequency-dependent and frequency-independent parameters. The authors have obtained error estimation in transient current and voltage parameters during single phase-to-ground fault in cable networks models that do not consider the frequency dependence on inductance (for discharge components the error is 1520 %, for charging components the error is equal to 510 %). It is shown that models with cable line parameters defined according to spreading speed of electromagnetic wave, can be used for approximate calculation of transient current and voltage to solve most of tasks of investigation of transient processes during single phase-to-ground faults. Application of the developed recommendations to determine three phase medium voltage cable lines parameters will increase the calculation accuracy of transient processes during single phase-to-ground faults in 6–10 kV cable networks. Only application of frequency-dependent models of cable lines allows us to provide required accuracy to develop methods of distant earth fault localization in 6–10 kV networks.

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Mathematical modeling of the three-phase high-voltage cable lines under the theory of multiterminal networks

2015 16th International Conference on Computational Problems of Electrical Engineering (CPEE) ◽

10.1109/cpee.2015.7333347 ◽

2015 ◽

Author(s):

Vadim Lobodzinskiy ◽

Lyudmila Maslak

Keyword(s):

Mathematical Modeling ◽

High Voltage ◽

Three Phase ◽

Cable Lines

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Impact of Cable Configuration on the Voltage Induced in Cable Screen during Work with One-Sidedly Ungrounded Cable Screen

Energies ◽

10.3390/en14144263 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4263

Author(s):

Aleksandra Schött-Szymczak ◽

Krzysztof Walczak

Keyword(s):

Cross Section ◽

Point Of View ◽

Network Configuration ◽

Cable Line ◽

Network Characteristics ◽

Ground Fault ◽

Network Operation ◽

Distribution Line ◽

The One ◽

Cable Lines

In the latest research, it has been proven that from the point of view of losses in a cable distribution line, the most advantageous operation is to work with two or one phase of metallic cable screen ungrounded. However, such an operation may cause changes in the network characteristics and thus the occurrence of undesirable phenomena. One of those characteristics is the overvoltages in those cable screens, which can lead to cable line damage. The simulation tests presented in this article are closely related to the unusual method of operation of the MV cable screens and their performance, and they address the question of whether in a given system ground fault overvoltages may be a significant threat to the operation of the cable. The research methods used to verify these risks are related to the simulation of the cable line operating states using the DIgSILENT PowerFactory program (DIgSILENT GmbH, Gomaringen, Germany). Overvoltage simulations were performed, taking into account changes in the network configuration, such as the method of cable screens grounding, the length of cable lines, the cross-section of the conductor and cable screen, or the method of operation of the neutral point. The results for the cable line modeled as a part of the MV network with the variables considered during the tests indicate the possible impact of the one-sidedly cable screen ungrounding on overvoltages in this cable screen. The obtained results at the level of a few kV in one-sidedly ungrounded cable screens show that the change of the configuration of the operation of these cable screens may affect the safety of the network operation.

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