Power Cable Lines Research Articles

Optimization the Arrangement of Power Cable Lines in Tunnel

In order to optimized the power cable layout design in tunnel, and improved the operation ability of the cable line, this paper analyzed the cable rating and the short-circuit force under different arrangements. 220kV cable circuit was simulated in the tunnel with conditions of the flat and the trefoil arrangements. The temperature and the rating of the 220kV cable under the condition of the two arrangements were calculated in this paper. The short circuit force peak value and its direction of the cable line under short circuit current of 50kA under the condition of the two arrangements were simulated in this paper. The results show that, the cable rating in flat arrangement is better than in trefoil formation. The value and the direction of the short circuit force in tunnel are better in flat arrangement than in trefoil formation. So it is suggested that the flat arrangement is preferred when conditions permit.

The capacity limitations of power transmission cable lines in the structure of civil and industry engineering networks

The present study analyses heat modes of high voltage cable lines typical for laying in the area of communications, different obstacles and engineering networks, such as, for instance, hot water supply lines. It is well-known that the load capacity of modern high voltage cable lines with a plastic insulation is limited by the maximum permissible heating temperature of 90 °C. This study focuses on two typical cases of heating mains influence on heat exchange of a power cable line with surrounding ground: 1) the rapprochement of a power cable line with a heating main - the segment of a parallel disposal of a cable line and a heating pipe; 2) the intersection of a cable line and a heating main - the area where the cable line going above the heating main crosses it at the angle of 90 degrees. We have proposed the model of a prolonged cylinder with inhomogeneous thermophysical and heat exchange parameters distribution along this cable for the temperature distribution along a power cable in terms of non-regular laying. The finite-element method has been used to solve the problem of cable line heating fields near heating main calculation. A quantitative analysis of the cases described above has revealed that the local cable temperature excess up to several tenths of degrees is typical for them. It leads to the transmission capacity decrease by 20-30 % and limits the cable line ability to cover peak loads occurring in industrial, natural or other disasters. Besides, cable line segment spillover out of permissible temperature mode leads to emergency, power shortage and further repairing efforts. While engineering and calculations of the cable lines modes, our proposed techniques allow avoiding critical temperature conditions which may lead to the consequences described above.

Effect of Power Line Conductor Resistance-to-Reactance Ratio on Voltage Magnitude during Two-Phase Faults at Electric Energy Grids

This paper deals with the effect of power line impedance characteristics on the retained voltage magnitude after a two-phase fault at electric power distribution or transmission networks. Specifically, the effect of resistance-to-reactance (R/X) ratio of power line conductors or cables on voltage magnitude during two-phase faults is studied with analytical mathematical expressions. The basic aim of this investigation is to create a tool for the automatic recognition of the type and the location of faults on electric power networks.

Design Technique and modification of Power line filter using passive lumped components

A unique design technique of power line filter is being proposed. It is based on the conventional technique of composite low pass filter. The equivalent circuit of the composite low pass filter is being presented in the two different modes by considering the modal propagation of noise. The consideration of composite LPF is taken into account in the design technique of power line filter. In order to accurately predict the insertion loss of the filter the effects of non-ideal behaviour of the passive lumped components are considered. It is based on the parasitic effect of the passive lumped elements. The filter is then characterized using S-parameters. The response of the filter's circuits is simulated using advanced design software (ADS). Keywords: Conducted emission, Composite filter, electromagnetic compatibility, lumped elements, and power line filter. I. Introduction Switching and modulation techniques are used for efficient use of electrical power. Widely used Switched mode power supplies (SMPS) for powering today's electronics loads is a most common example. Unfortunately, all the power control techniques deliberately distort sinusoidal wave form of power frequency and generate unwanted interfering signals. Obviously, they all are often cited as one of the main source of conducted emission (CE). Usually the power supplies which are using controlling techniques cannot comply with the strict electromagnetic compatibility (EMC) regulations. In order to meet the limit set for conducted EMI, power supplies require a filter at its input. Conducted EMI generated through particular equipment gets coupled into other equipments mostly through power line cables. CE can be controlled by using filters and increasing line impedance. Conducted EMI has two components: The common mode (CM) interference and differential mode (DM) interference. The coupling mechanisms of these interferences are different (4). The difference in the direction of propagation of these coupling currents along the phase and neutral line, leads to differential mode ( ) current and common mode ( ) current. Therefore design of EMI filters demand decoupling of these two modes (2). This paper attempts to describe a design technique for Power Line filter using classical design technique. 1.1 Characterization of common mode & differential mode currents

Estimation of multi‐conductor powerline cable parameters for the modelling of transfer characteristics

The modelling of transfer characteristics of low-voltage power distribution networks for Power Line Communications requires the knowledge of the electrical parameters of the cables comprising these networks. In this study, a method is developed for characterising the power line cable parameters. In complement to many existing approaches, the authors estimate the cable parameters from a limited set of measurements. Measurement results can take into account fabrication tolerances, bending of the cables etc., which help to obtain more accurate results. A multi-conductor powerline cable has multiple, coupled propagation modes with corresponding primary parameters. Based on multi-conductor transmission line theory, the authors propose a practical measurement approach to derive the parameters separately. A previous analysis was made for four-conductor powerline cable. Here, it will also be generalised for three-conductor cables. With the parameters, the transfer function of the same kind of cable can be obtained easily. The approach is validated by comparing the deduced transfer function of a power line cable with the directly measured one.

Cable Fault Recognition Based on the Wavelet Energy Spectrum of Mode Components

When a fault appeared in a power cable transmission line, the transient current with high frequencies would be produced in the system. Three independent mode components could be obtained by applying the phase mode transformation to the transient current. For different types of the faults, the three independent mode components have different features. Based on wavelet energy spectrum of mode components, a method for cable fault recognition is developed in this paper. First, the fault current is decomposed by using Karenbaue transformation matrix. Then, wavelet transformation is uses to obtain the coefficients of the high frequency components which reflect the original signal high frequency energy. Finally, based on the wavelet energy spectrum method and the detailed coefficient manipulation, the equivalent norms of the mode components are obtained. Compared with the traditional fault recognition method, the new method depends less on zero mode component in two-phase short to ground state, and it can recognize the fault class in the cases of different fault positions, different fault path resistances and different inception angles.

Medium Voltage Smart Grid: Experimental Analysis of Secondary Substation Narrow Band Power Line Communication

This paper is focused on the possibility of employing narrow band power line communication (PLC) in medium voltage (MV) distribution networks. The topic is investigated by means of both simulations and experimental tests, which were carried out in the distribution network of Ustica Island. In detail, a two-way MV communication was tested between two secondary substations connected by an MV cable power line. Each substation has a by-pass connection at MV bus-bars and an MV/LV oil filled power transformer. In this paper, the MV and the PLC systems under test are described and the experimental tests are presented, which were carried out to evaluate the parameters of the simulation model. The aforesaid model is described and a comparison is shown between simulation and results of experiments, which were carried out in the presence of voltage net, i.e., 24 kV. Finally, the possibility is investigated of a reliable communication and the faster achievable bit-rate; the analysis is performed by means of further experimental results of several communication tests, which were carried out with different modulation techniques.

An Efficient Method Based on the Electromagnetic Time Reversal to Locate Faults in Power Networks

This paper presents a new method based on the electromagnetic time-reversal (EMTR) theory for locating faults in power networks. The applicability of the EMTR technique to locate faults is first discussed. Using the classical transmission-line equations in the frequency domain, analytical expressions are derived to infer the location of the fault. The accuracy of the proposed method is then discussed in relation to the number of observation points adopted to record the fault-originated electromagnetic transients. Then, this paper illustrates the extension of the proposed method to the time domain. The experimental validation of the proposed method is presented by making reference to a reduced-scale coaxial cable system where real faults are hardware-emulated. Finally, the application of the proposed EMTR-based fault-location method to Electromagnetic Transients Program-simulated cases is presented. The simulated test cases are: a mixed overhead/coaxial cable transmission system and the IEEE 34-bus distribution test feeder. Compared to other transient-based fault-location techniques, the proposed method presents a number of advantages, namely, its straightforward applicability to inhomogeneous media (mixed overhead and coaxial power cable lines), the use of a single observation (measurement) point, and robustness against fault type and fault impedance.

Inter‐wire Coupling Model Development for Health Monitoring of Cable Structures

AbstractStructural Health Monitoring (SHM) allows the integrity of a system to be monitored in situ, detecting weaknesses as they form. Due to the waveguide nature of cylindrical structures, ultrasonic waves can be used to detect defects in cables over large distances. Considering that common power line cables consist of several individual wires, a straightforward energy‐based approach is chosen to simplify the model development. The purpose of this investigation is to extend the current coupling model to include n wires and to verify this model for a seven‐wire cable, experimentally. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Achieving High Data Rate in Multiband-OFDM UWB Over Power-Line Communication System

Theoretical studies indicate that a transmission data rate of up to gigabits per second can be achieved over low-voltage (LV) indoor power-line cables. Achieving a very high data rate (up to 480 Mb/s) is expected by applying WiMedia multiband-orthogonal frequency-divison multiplexing (MB-OFDM) standard for wireless ultra-wideband (UWB) communication over the power-line channel. However, the viability of this concept needs to be tested experimentally. This paper presents a novel design of demonstration system for the UWB over power-line communication technology. The demonstration system consists of an MB-OFDM UWB kit and is capable of transmitting very high data-rate signals over the LV power-line cables. It provides means to evaluate the performance of the UWB over power-line communication systems and analyze its viability in actual home networking scenarios.

Innovative calculation methods of the magnetic field from single and double-circuit twisted three-phase cables widely used in MV and LV installations

Abstract This paper proposes a simple innovative formula for the calculation of the magnetic field generated by a single and a double circuit twisted three-phase power cable line. The formula results a good approximation of the rigorous analytical one and at the same time is much more accurate than the approximated formula found in literature, as demonstrated by some cases of a twisted three-phase power cable used for power distribution at the medium voltage level. The effectiveness of this simple innovative formula is also examined in the case of a double-circuit twisted three-phase power cable line following the’ worst case’ approach and concluding at proposing an approximate expression for the total magnetic field generated by both twisted three-phase power cables.

Electrocution by Arcing

Accidental electrocution during working activities account for a considerable amount of morbidity and mortality. Workers often misjudge the danger of electric wires or high-tension power cables, thereby exposing themselves to electrocution hazard. This article describes a nonfatal case of injuries by arcing from high-tension power-line cables involving a young farmer who was thrashing an olive tree by means of aluminum ladder. The circumstances surrounding the manner of electrocution and the features of electric injuries are presented and discussed.

Simulating wet snow loads on power line cables by a simple model

Abstract A wet snow event in the northwest part of Germany caused extensive damage to electric power lines in November 2005. Maximum wet snow loads of approximately 50 Nm − 1 were estimated by evaluating the snow deposit diameter from photographs and the snow density from meteorological data. A simple wet snow accretion model was applied to reconstruct the snow accretion process. The maximum wet snow loads estimated by the model are in good agreement with the observations when the model input parameter, visibility, was adjusted by a constant factor for night-time observations. The improved wet snow accretion model was also applied to historical weather data for the area demonstrating the power and weaknesses of the extreme value analysis of wet snow events.

Development of Fault Detection System using Wavelength Division Multiplexing Transmission of Optical Fiber Current Sensor

A fault detection system is applied to power lines consisting of both overhead power line and underground power cable in order to detect a fault on the underground power cable section and prevent the automatic reclosing.The fault detection system using optical fiber current sensor has two subjects. The fist subject is that we have to use wound-type current transformer together, when applying the fault detection system to single-core underground power cable. The second subject is that we are not able to detect three-phase short-circuit fault in using the fault detection system.This paper describes that we developed a new fault detection system using optical fiber current sensor by applying the multiplex transmission technology of optical fiber current sensor signal in order to solve these subjects.

Corrosion protection of 6-10-35-110-220-kV cable lines in St. Petersburg

Data on the corrosion protection system of the 6-10-35-110-220-kV power cable lines in St. Petersburg are given. Information on how to select equipment for units of cathode protection of 110-220-kV, oil-filled cable lines is given.

Optimization of power cable production lines for EPM/EPDM elastomers by genetic algorithm with different peroxides

AbstractEPM/EPDM elastomers are widely used for the insulation of high and medium voltage electric cables. Insulator mechanical properties depend on the extent of vulcanization, which is obtained by manufactures using a number of different peroxides as cross‐linking agents. Vulcanization occurs in the continuous vulcanization tube, a pressurized tube filled with nitrogen at high temperatures. Then, water and/or air are used to cool the cable at ambient temperature. Changes of process variables cause considerable changes in insulator physical properties. In the present article, a genetic algorithm with zooming and elitist strategy is used for the determination of optimal production lines parameters to use to maximize rubber output mechanical properties. Nitrogen temperature Ts and exposition time t are assumed as production parameters to optimize, whereas two different output mechanical properties (tensile strength and tear resistance) are considered as objective functions. Several optimization problems are analyzed both for medium and high voltage cables. A final multiobjective optimization is presented with the corresponding Pareto frontier, where objective functions are represented by tear resistance and tensile strength. Optimal production Ts and t are obtained for all the cases analyzed. Numerical simulations show how different peroxides and insulator thicknesses sensibly influence optimal production variables. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

22.9[kV] CNCV케이블 지중배전계통의 3상 비일괄 동심증성선 다중접지방식에 대한 이론적고찰

현재 국내에서 사용되고 있는 22.9[㎸]-y 배전 방식은 지중 케이블로 전력을 공급하고 있으며, 선로 운영상 배전 케이블 선로의 동심중성선을 케이블 접속 구간마다 3선 일괄 접지하는 3상 일괄 다중접지방식을 채택하고 있다. 이 방식에서는 동심중성선에 부하 전류의 약 40[%](전력구)~50[%](관로)의 동심중성선 순환 전류가 발생하고 있다. 본 논문은 이와 같은 문제점을 해결하기 위하여 새로운 3상 비일괄 동심중성선 다중접지방식을 제안하고 있으며, 케이블의 허용전류계산, 케이블차폐층의 유기전압 및 선로에서 발생하는 유도장애등의 기술적인 문제들을 종합적으로 해석하고 있다.

Modeling and Analysis of Common-Mode Current Propagation in Broadband Power-Line Communication Networks

This paper proposes a new approach to modeling the common-mode (CM) current propagation path of electrical power-line cables for broadband power-line communications (PLC). In this approach, a CM current propagation model for a three-wire power-line cable is developed using the multiconductor transmission-line theory. The model is used to study the electromagnetic-interference radiation mechanism from the PLC network in the frequency range of 1 to 30 MHz. The accuracy of the model is verified through numerical simulations and practical measurements conducted on the actual power-line network. The developed model allows us to predict the CM current in the power-line cable with reasonable accuracy.

Study on Subjective Symptoms and ELF-Magnetic Fields Exposure Compares Underground-Transmission cable With Overhead Power Line

ISEE-866 Objective: This study proposed to evaluate the relativity of exposure of extremely low frequency magnetic fields and subjective symptoms between elementary school students residing near residential overhead power lines and those residing near underground transmission cables. Material and Methods: After choosing the residential overhead power line and underground transmission cable regions, personal measurement and assessment of 60 Hz magnetic field was investigated as collecting the bag of EMDEX lite (Enertech) which the volunteers carry for 24 hours and questionnaire between elementary school students. Principal components analysis of the symptoms resulting in volunteers in the environment of nearby power lines are the following: headache, fatigue, dizziness, failure of memory, a drop in the power of concentration, and occurrence of subjective symptoms. Therefore, to compare symptoms in the case of the construction of 154 kV lines conversion from overhead transmission lines to underground transmission lines. Results: The result of group's subjective symptom about elementary school students living in environment nearby residential overhead power line and underground transmission cable. As a result, the complaint rate of failure of memory of elementary school students nearby residential overhead power lines is significantly higher than that of elementary school students nearby underground transmission cables (P-value: 0.0065). So ELF-magnetic fields exposure for residential overhead power lines was 0.74 mG and for underground transmission cable was 2.87 mG (P-value <0.0001). We found no association between power lines (residential overhead power lines or underground transmission cables) and other subjective symptoms like headache, fatigue, dizziness, a drop in the power of concentration, and occurrence of subjective symptoms. But elementary school students nearby residential overhead power lines showed a higher complaint rate than that of those nearby the underground transmission cables. Conclusions: Further studies have to be conducted because these results show that EMF may affect a change in the children's neurobehavior.

The Influence of Load Impedance, Line Length, and Branches on Underground Cable Power-Line Communications (PLC) Systems

An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this paper investigates the effects of load impedance, line length, and branches on such systems, with special emphasis on power-line networks found in Tanzania. From the frequency response of the transfer function (ratio of the received and transmitted signals), it is seen that the position of notches and peaks in the magnitude are largely affected (observed in time-domain responses too) by the aforementioned network configuration and parameters. Additionally, channel capacity for such PLC channels for various conditions is investigated. The observations presented in this paper could be helpful as a suitable design of the PLC systems for better data transfer and system performance.