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This paper has investigated the possibility of glass insulator breakage by resonance and accelerated degradation based on an analysis of natural frequency characteristics of glass insulators on the KTX overhead line and behavioral characteristics of the overhead line on site. The natural frequencies were formed within the range of 10 kHz, and the largest amplitude was observed at 5.15 kHz. The largest frequency that was imposed on strut tube glass insulators was 80 Hz with 1.13 g of vertical vibration in the viaduct section, the largest vertical vibration (0.38 g) was detected at 103 Hz in the open route section. When site frequency and natural frequency of strut tube glass insulators were compared in terms of characteristics, the resonance was not the same. In both the viaduct and open route sections, it seems that the impact by vertical vibration in strut tube glass insulators is large. Through this study, therefore, it has been confirmed that the failure of the glass insulator has nothing to do with resonance. In addition, no damage was detected in the accelerated degradation test. [ABSTRACT FROM AUTHOR]

For the problem of lightning breakage of covered conductors on overhead distribution lines, two kinds of b-kV surge arresters, namely a metal-oxide arrester with a ring-shaped series gap and stab electrode metal-oxide arrester with series gap were developed in this paper. Their structure, installing mode, and experiments were presented. Large amounts of lightning impulse flashover tests validate that these arresters have good effects. Based on these developed arresters, the protection measure for a 10-kV feeding line in substations was proposed. Now these arresters have been applied in China and have the potential for wide applications prospect. [ABSTRACT FROM AUTHOR]