Abstract: In this study, the effects of harmonics on underground power cable are investigated considering a real system. For this purpose, firstly, harmonic measurements were carried out under middle voltage in underground distribution cable system and then a Matlab/Simulink model has been constituted under the light of the measured data. The results indicate that the harmonics cause the excessive temperature rise due to the power losses in the cable conductor and the cable life is affected by the temperature rise. Therefore a derating factor is purposed to reduce the cable ampacity in this study as well.

Abstract: During the last decade, Very Low Frequency (VLF) testing for extruded distribution cables has gained interest among the North American utilities. The increasing interest is evidenced by recent research publications and discussions inside the expert community in which standards are being proposed and continuously discussed. While there is a general consensus as to the meaning of insulation dielectric properties, many open issues still remain for discussion in order to produce a more accurate evaluation. Consequently, this paper will discuss a number of the practical issues that arise when making these measurements at VLF on field aged and non-aged cables, particularly Tan δ measurements. The discussion is based on data from laboratory experiments and field testing.

Abstract: The analysis of the limitation of AC voltage withstand tests for XLPE power cables shows that the goal of the AC voltage withstand test should not be to expect too many faults in power cables. An AC voltage withstand test could only be a simple examination of installation engineering. So the DC voltage withstand test and charging test for 24 hours are still simple and useful methods for voltage withstand tests of medium and high voltage XLPE power cables.

Abstract: In this contribution based on field application of advanced diagnostics a systematic approach for condition assessment of HV power cables is discussed. Based on the assumption that there is not one dominant failure process in HV cable networks in addition to partial discharges dielectric diagnosis has also be included to determine the actual condition of service aged e.g. XLPE, oil-filled, gas-pressurized cable insulation systems.

Abstract: This paper presents a partial discharge (PD) measurement for cable terminators of XLPE power cable. The power cable of rated voltage 24 kV and a cross sectional area of 240 mm2 was used in the experiment. The partial discharge level and dielectric loss are very important factors to indicate the insulation quality of power cable. Therefore, measurement techniques of partial discharge and dielectric loss are required in high voltage applications. This paper proposes a design and construction of a cable terminator by using acrylic tube. Inside of cable connector, the maximum high pressure air can be compressed more than 3 bar. In order to implement the partial discharge and the dielectric loss (tan?) techniques, the cable terminator has to be tested according to IEC standards No.60502, No.835-3 and No.270. It can be found that the cable terminator testing gives the satisfactory and reasonably accurate results from the measurement techniques. In addition, the cost of construction is much cheaper than a commercial module.

Abstract: Very low frequency (VLF) voltage test on-site has been applied widely for evaluating the status of installation and operation of medium voltage power cable lines. For optimizing and validating the test voltage and test time, the validity, equivalency and relationship of test voltage and test time of VLF voltage test is discussed and analyzed in this paper. The results of research and optimization in the paper have proved and verified that the VLF voltage test method of 30U0 test voltage and 40 min test time is a better choice for checking and verifying the safe operational life of power cable lines, and 2.S U0/25 min or 3U0/25 min is suggested for verifying the safe operational life of aged cable line that has been in service more than 7 years. VLF voltage test may establish the present status of dielectric quality of power cable lines.