KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Chaisiri, P.

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Polarization and Depolarization Current Characteristics of Degradation Stator Insulation of A Rotating Machine
    (2018-11-14)
    Phumipunepon, N.
    ;
    Chaisiri, P.
    ;
    Thungsook, K.
    ;
    Pattanadech, N.
    This paper presents the dielectric analysis of the simulated degradation stator bars compared with unmodified stator bars. The stator bars used in the experiments were acquired from the 30 year in-service synchronous machine of a hydro power plant. The simulated degradation stator bars were prepared and comprised of outer corona protection degradation stator bars, partial discharge (PD) stator bars and thermal degradation stator bars. In case of the outer corona protection degradation, the outer corona protection surface was abraded for small damages. For PD degradation bar, the PD existing bars were used for the experiment. In case of thermal degradation stator bars, they were divided into three groups, the first group of stator bars was heated in the oven at 100°C for 12 hours. The second and third group stator bar was heated at 120 and 140 °C respectively for 12 hours as well. After preparing the test objects, the polarization and depolarization current (PDC) were performed with the mentioned stator bars. The PDC test results were recorded. The test results showed that the polarization currents and depolarization currents, the conduction currents and the capacitances of the simulated degradation stator bars were clearly different from these of the unmodified stator bars. Other analysis parts are reported also in the paper. This paper suggests that PDC test technique is one of the effective methods for evaluation of the stator bar insulation characteristics.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Dielectric properties of mineral oil compared with natural ester
    (2017-11-29)
    Jariyanurat, K.
    ;
    Nimsanong, P.
    ;
    Chaisiri, P.
    ;
    Maneerot, S.
    ;
    Kitcharoen, P.
    In this paper, dielectric properties of the mineral oil, ELECTROL A, and the natural ester, FR3, are comparatively investigated. AC breakdown voltages, dielectric dissipation factor, relative permittivity, partial discharge inception voltage and partial discharge of the mineral oil and of the natural ester are tested. In order to verify the capability in practical use of the mineral oil and the natural ester for transformer insulation systems, the impregnation of such liquids with pressboard insulation is performed. The impregnated pressboards are tested in the laboratory to measure the AC breakdown voltages. It is found that the natural ester shows superior dielectric properties to the mineral oil except the dielectric dissipation factor.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Transient equivalent circuit of a horizontal grounding electrode
    (2012-12-31)
    Yutthagowith, P.
    ;
    Kunakorn, A.
    ;
    Potivejkul, S.
    ;
    Chaisiri, P.
    This paper proposes an equivalent circuit of grounding electrode which has validity upto a frequency range of sub-sequence stroke lightning current. The equivalent circuit is modelled by lumped and distributed parameters based on quasistatic assumption. In this study, only a grounding electrode installed horizontally is in consideration. The limitation of the uniform distributed equivalent circuit of a grounding electrode is presented. The non-uniform distributed equivalent circuit is proposed. The proposed equivalent circuits are verified by comparison of the results of ground potential rise computed by the proposed circuit, the partial element equivalent circuit method, and available experimental data. The proposed equivalent circuit can be adapted for being the models for development and design of the grounding system for lightning protection system in transmission and distribution systems in an effective way. © 2012 IEEE.