Current Carrying Capacity Of Cables Research Articles

Study on temperature rise characteristics of 110 kV XLPE cable under different service years considering dielectric loss

This paper studies temperature rise characteristics of 110 kV XLPE cable under different service years. When the load is 900 A, the maximum temperature of the cable under 0, 15 and 30 service years is 335.5 K, 372.96 K and 393.88 K respectively. Compared with the data obtained from non-aged cable, the temperature increase for samples operating for 15 and 30 years is 111.15% and 117.4% higher. For these samples, the proportion of heating due to cable dielectric loss is 2.77%, 25.45% and 34.78%. The research content of this paper provides a basis for the research on the optimal current carrying capacity of cables with different service years, provides a reference for the actual application of cables, and has guiding significance for the research on prolonging the service life of cables and improving the utilization rate of cable resources.

Conductor Temperature Monitoring of High-Voltage Cables Based on Electromagnetic-Thermal Coupling Temperature Analysis

As a key state parameter of high-voltage cables, conductor temperature is an essential determinant of the current carrying capacity of cables, but in practice, this is difficult to measure directly during the operation of high-voltage cables. In this paper, the electromagnetic-thermal coupling analysis model of a 110 kV high-voltage cable is established using the finite element analysis software COMSOL. By analyzing the temperature distribution law of high-voltage cables under different load currents and ambient temperatures, the relationship between the change in the high-voltage cable surface temperature and the conductor temperature is deduced, which allows the monitoring of the high-voltage cable conductor temperature. Taking the 110 kV cable of the Yanzhong line in Shanxi Province as an example and using the electromagnetic-thermal coupling temperature field analysis method, the conductor temperature of the high-voltage cable can be measured using the data obtained from the cable surface temperature, which is measured by the self-developed Raman Distributed Temperature Sensor (RDTS) system with a maximum measurement error of about 2 °C. The method is easy to use and can achieve the accurate measurement of the conductor temperature without damaging the cable body.

Analysis of Current Carrying Capacity of Power Cable Based on DTS

This article uses a distributed optical fiber temperature measurement system (DTS, Distributed Temperature Sensing) to fix the temperature measurement optical fiber on the surface of the power cable, collect the real-time operating temperature of the power cable, conduct the ampacity test, and analyze the cable laying method and depth, soil temperature, Soil thermal resistance coefficient, cable spacing and irradiation strength and other test conditions, the impact on the current carrying capacity of power cables. According to the real-time monitoring temperature of the cable, the alarm can be made when the cable temperature is too high or the temperature rise speed is too fast. And on the basis of determining the working temperature and load operating conditions of the cable conductor core, dynamically calculate the current carrying capacity of the cable, which is conducive to improving the performance of the power cable and increasing the load capacity of the power cable.

Determination of the current carrying capacity of cables using the finite element method

Abstract Finite element network is composed to determine the temperature rise within and around a three phase 110 kV underground cable bunch that makes it possible to analyze both the transient and the steady-state load conditions for cyclic daily load diagrams. The cable trench profile, bedding made of special mixtures, concrete and asphalt cover and soil and ground surface heat conductance effects are considered including the soil drying out phenomenon. An iterative procedure is suggested for determining the maximum allowable peak load for typical hourly cable load diagrams. The proposed approach was applied to assess the maximum ampacity of a 110 kV cable laid in Belgrade urban area as well as to quantify the favorable effects of the bedding mixture.

External thermal resistance of aerial bundled cables

The calculation of the current carrying capacity of cables in air by the IEC method requires that the external thermal resistance be known, determined from the temperature-dependent heat dissipation coefficient, which includes both convection and radiation losses, and the temperature rise of the surface of the cable. To extend the method to twisted bundled cables, still-air and wind tunnel tests have been performed to obtain convective heat transfer data for a single core and for bundles of two, three and four cores. It is shown that the choice of an effective diameter for the bundle affects the correlation between the Nusselt number and the Rayleigh or Reynolds number, and it is suggested that the diameter of the circle which circumscribes the bundle be used.

Cable System Design For Cathodic Protection Rectifiers

Abstract The design of any current-carrying cable system involves certain basic factors, which may be listed briefly as follows: Ability to meet mechanical stresses and other environmental requirements; Ability to meet voltage attenuation limits; Ability of the insulation to withstand applied voltages; Ability to meet limitations on current due to temperature and insulation stability; Conformance to Kelvin's Economic Law; Conformance to legal codes, safety rules, and similar requirements. The importance of each of these factors is discussed in the light of cathodic protection require-ments and installations. Emphasis is placed on cable systems which connect the direct current output terminals of the rectifier to ground beds and to the protected metal structures. Frequently engineers disregard one or more of the six factors in designing cathodic protection cable connections. For example, the tendency is to design to fit the current-carrying capacity of cables as set forth in the various handbooks and to ne...

A-C Resistance of Large Size Conductors in Steel Pipe or Conduit

The determination of the proper conductor size to carry a given power load on cables installed in steel conduits or pipes has been subject to assumptions which were not too satisfactory. The Insulated Power Cable Engineers Association engaged the Electrical Testing Laboratories to conduct a research project to large conductors installed in steel pipes. This paper reports the results of the research and gives suggested values of ratio of a-c to d-c resistance for conductor sizes up to 2,500,000 circular mils. It is felt that more accurate and uniform calculations of current carrying capacity of cables in conduit in air, or in pipe in the ground can be attained by use of the a-c/d-c conductor resistance ratios set forth herein, than by assumptions used previously, and therefore the data reported herein will be of benefit to both the manufacturer and the power user.