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Author: search.filters.author.Lacharochana, Sakda

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    Item type:Publication,
    Effect of Longtime Sheath Current on Insulation Screen of 115kV XLPE Underground Cable
    (2024-01-01)
    Jariyanurat, Kittipod
    ;
    Jeenmuang, Siwakorn
    ;
    Udomluksananon, Patt
    ;
    Kerdmanee, Sittipong
    ;
    Lacharochana, Sakda
    Due to the need to extend the life of underground cables that are universally installed and used in power plants in Thailand, The life assessment must be concerned with advanced techniques, both chemical and physical, exactly. The components that needed to be analyzed were divided into two main groups: the insulation and physical systems. One of the most requisites is pyrolysis. Pyrolysis can occur in the underground cable system with many factors, for instance, the ambient temperature, overload, loss of connector, and longtime sheath current. Thus, this paper described the effect of the longtime sheath current on the insulation screen of 115kV XLPE underground power cable. Sheath current that ran into the system for longtime effectively effected to the insulation screen by destroying the structure of chemical properties leading to the short lifetime and getting the high risk to breakdown with the continue use.
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    Effect of Sheath Current on the Lead Sheath of 115kV XLPE Underground Cable
    (2024-01-01)
    Jariyanurat, Kittipod
    ;
    Jeenmuang, Siwakorn
    ;
    Chumpiboon, Komin
    ;
    Kerdmanee, Sittipong
    ;
    Lacharochana, Sakda
    Currently, underground cable systems are extensively employed in power generation and distribution due to their superior reliability, stability, and safety. Given the significant investment and critical role of these systems, it is essential to rigorously assess their lifetime and performance. Key factors affecting the lifespan and life assessment of underground cables include the insulation system and the physical components of the power cable. Among these, sheath current is a notable factor that contributes to cable deterioration. This paper investigates the impact of prolonged sheath current on XLPE power cables, which have been in operation for approximately 25 years, associated with a 115kV generator unit. Specifically, the study focuses on the degradation of the lead sheath due to sheath current exposure. It was observed that the lead sheath exhibited signs of degradation, including tracking, which affected various layers, such as the lead sheath itself, the semi-conductive tape, and the semi-insulation. The research highlights that while sheath current did lead to observable tracking on the lead sheath, the overall impact on the cable's lifetime was minimal. An analysis of the lead sheath's properties, based on fundamental physical characteristics, revealed that long-term exposure to sheath current primarily caused minor physical tracking on the sheath's surface rather than significantly affecting its lifespan. This finding suggests that although sheath current can induce localized degradation, its effect on the overall functional longevity of the lead sheath is relatively limited.
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    The Study of Partial Discharge Test on Service-Aged Cable Termination
    (2023-01-01)
    Laohapongpan, Trinai
    ;
    Wiangtong, Theerayod
    ;
    Kerdmanee, Sittipong
    ;
    Lacharochana, Sakda
    ;
    Jeenmuang, Siwakorn
    This paper presents the partial discharge (PD) testing on the plug-in gas-insulated switchgear cable termination taken out of service. The shield electrodes were designed to geometrically electric field control in the area of the insulation screen edge of the cable part. The PD test of the cable termination was performed. In addition, a computed radiography technique with X-ray was also performed to evaluate the mechanical integrity of the supporting spring of the cable termination. The fatigue of the supporting spring was evidenced. Moreover, the cable termination was disassembled and re-assembled to perform the PD test again. The PD characteristics, including PD magnitude, PD inception voltage (PDIV), and phase-resolved PD (PRPD) patterns, were reported. The PD test results revealed that the PDIV was lower than the operating voltage. Besides, the PRPD patterns exhibited internal discharge inside the cable termination. From the PD test results and computed radiographic, it was assumed that they might be caused by discharge in the interface between the stress cone and epoxy insulator.