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    Item type:Publication,
    Evaluation of UHF transfer function in a power transformer for real-time partial discharge detection
    The UHF transfer function is significant for a short-range communication system, e.g., a real-time diagnosis of partial discharge (PD). Real-time diagnosis of the PD has become a challenging topic of improving the diagnosis of high voltage equipment, including a power transformer. Further, the PD detection in high voltage equipment is critical since the PD can cause severe damage to electrical systems. The PD detection methods are classified by a phenomenon of the PD. The PD detection by electromagnetic (EM) method is regulated by IEC TS 62478, which specified the UHF band for the PD detection in power transformers. Hence, an evaluation of frequency characteristics is essential to achieve an excellent diagnostic performance. In this paper, a complex form of channel analysis is applied with the PD detection method. The measurement model in a power transformer is proposed. The optimum receiver is introduced to maximize SNR and hence it is easy to analyze the results. The results were analyzed by using magnitude, phase, group delay, received waveform, and path loss parameters. The results show that the measured channel is affected by the structure of the power transformer. The contribution of this research is useful for improving the precision of the PD detection with EM method and building an accurate real-time partial diagnosis via a smartphone or laptop computer.
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    Item type:Publication,
    Evaluation of DTTV Transmission for SFN with Minimum Threshold in Thailand
    (2020-12-01) ; ;
    Ruckveratham, Bundit
    The digital terrestrial television (DTTV) transmission based on digital video broadcasting-terrestrial second generation (DVB-T2) for a single frequency network (SFN) shall be studied. The DTTV signal performance is very important. Therefore, the performance of DTTV should be studied. SFN is a key factor in DVB-T2 technology due to the benefits of SFN. In order to evaluate the DVB-T2 performance, this research had investigates broadcasting reception threshold of DVB-T2 signal. The experiment was done in a laboratory of Mass Communication Organization of Thailand company, Thailand, and field experiment was done in urban area of Sing Buri, Thailand. The measurement model was set up to measure the the DTTV performance parameter with respected to guard interval delay time of two SFN transmitters. The acceptable result of minimum power, received signal, CNR, MER, and transmission loss are presented. The reliability of the result was validated by using polynomial. The measurement results provided a useful information for optimization and modeling of DTTV broadcasting for SFN system with DVB-T2 in Thailand.
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    Item type:Publication,
    Measurement and Modeling of DTTV–SFN Propagation in Thailand
    (2020-12-01) ; ;
    Ruckveratham, Bundit
    Digital terrestrial television (DTTV) with a single frequency network (SFN) in Thailand is based on digital video broadcasting-terrestrial second generation (DVB-T2) standard. The signal quality of DTTV–SFN is very important. DVB-T2 is improved from traditional terrestrial television broadcasting technology in term of modulation which is coded orthogonal frequency-division multiplex. Therefore, the performance of DTTV should be study. SFN is a key factor in DVB-T2 technology due to the benefits of SFN. In order to evaluation the DVB-T2 performance, this research had investigated delay characteristics , path loss, and broadcasting reception threshold of DVB-T2 signal. The measurement was done in an overlap area of DTTV–SFN in Thailand. The measurement model was set up to measure the delay time, received signal power, and network quality parameters between guard interval time of three transmitted stations. The results present a comparison of delay characteristics between each received positions and a comparison of path loss between free space case and measurements. An acceptable result of spectrum variation, CNR, MER, and noise margin are presented which have the average value equal to 3.03 dB, 22.62 dB, 7.83 dB, and − 5.54 dB, respectively. The contribution of this research provide a measurement and modeling of DTTV–SFN in Thialand which the results are presented a useful information for optimization and modeling of DTTV–SFN system in Thailand.