油浸式高压套管局部放电非接触式特高频检测

变压器套管是承担引出线与变压器箱体绝缘的重要支撑装置,现有变压器套管潜伏性放电故障检测技术及时性差且灵敏度较低,而特高频技术抗干扰能力强且可实现非接触式检测。文中提出一种基于特高频检测技术的套管局放检测方法,建立35 kV套管的局放仿真模型并开展真型套管不同类型缺陷的局放试验。所得结论为:电容屏间油纸和外侧油道都是特高频电磁波传播的有效路径;传播过程中横电波(TM波)从-16 dB大幅衰减至-5 dB,横磁波(TE波)初始成分不足1%,主要成分为横电磁波(TEM波);特高频段能量主要集中在0.3~1.5 GHz。通过设置无接触特高频传感器即可实现套管的带电检测,确保电力变压器运行安全可靠。

Non-contact partial discharge detection of high voltage oil-impregnated-paper bushing based on UHF technology

The transformer bushing is an important device to support the transformer lead-out line, but it cannot be detected in time or the detection sensitivity is low for latent discharge faults of bushing. UHF (Ultra-high Frequency) technology has high an-ti-interference ability and can realize non-contact detection, which is a feasible technology for PD (partial discharge) detection of bushing. In order to analyze the propagation characteristics of UHF electromagnetic waves in the bushing, this paper establishes the PD simulation model of 35 kV bushing and carries out different types of PD tests of bushing, draws relevant conclusions: Both oil-impregnated paper between capacitance and the oil channel are effective paths for UHF electromagnetic wave propagation. TM waves greatly attenuate during propagation (-16 dB~-5 dB) while TE waves have few initial components (less than 1%), the main composition is TEM wave. The main energy of the UHF band is concentrated in the range of 0.3 GHz to 0.8 GHz and different types of PD of the bushing corresponds to different characteristic spectra. Therefore, the on-line monitoring of the bushing can be realized by setting the non-contact UHF sensors out of the bushing to improve the safety and stability of the transformer operation.