In SF6 electric equipment, the moisture content of SF6 gas is an important index to supervise the safe operation of the equipment. This paper introduces the source of water content in SF6 gas and its harm when the water content exceeds the standard, and analyzes the influence of water content on decomposition products under discharge of solid metal particles and abnormal heat. In view of the excess water content in SF6 gas, the corresponding control measures are formulated to ensure the safe and reliable operation of SF6 equipment.
The abnormal heating test model of GIS internal insulation was established. The abnormal heating test of aluminum-filled basin insulator under steady state current was carried out. The content of SO2, H2S and CO2 remained stable at the beginning of the experiment, and the content of SO2, H2S and CO2 increased obviously when the experiment reached a critical point. The abnormal heating test model of the inner insulator of the gas insulated switchgear was established. The overheat test of solid insulation was carried out under the condition of 0.3 MPa absolute pressure in the gas chamber and without adsorbent. The overheat fault duration was 6 h and the overheat fault temperature was respectively 200℃、250℃, 300℃ and 350℃, the decomposition products of SF6 are CO, CO2, SO2, SOF2, H2S, COS and CF4. The generation mechanism of SF6 decomposition products under abnormal conditions is also analyzed to guide the judgment of internal faults and operation defects of equipment on site and ensure the safe and stable operation of power grid equipment.
As SF6 mixture gas gradually replaces pure SF6 gas as insulation gas for switch equipment, the decomposition products of SF6 mixture gas such as Quantitative analysis have been put on the agenda. Although SF6 gas mixture is similar to high purity SF6 in physical chemistry characteristics, there are great differences in decomposition product gas analysis algorithms. If we still use high purity SF6 gas decomposition product detection equipment and algorithms, the result will cause the quite big measurement error, can not satisfy the measurement precision request. The Gas chromatography can be used for quantitative and qualitative analysis of the characteristic gas components of the decomposition products by valve switching, selection of supports, and optimization of chromatographic conditions. The Sulfur hexafluoride Gas chromatography enables the detection of decomposition products of Sulfur hexafluoride gas mixtures under laboratory and field conditions. It is convenient to find and deal with the defect and hidden trouble of the equipment, and carry on the comprehensive condition evaluation. This can not only ensure safe and stable operation, but also provide technical support for power grid construction.
A passively Q-switched (PQS) Tm:YAP laser was faultlessly realized with the WSe2 nanosheets as the saturable absorber (SA). A 0.97-W average output power at 1987.5 nm and a 459.0-ns pulse duration were obtained with a 9.5% optical conversion efficiency, and a 11.2-μJ pulse energy and a 24.4-W peak power were gained with a 10.2-W pump power. In addition, the beam quality factors of 2 1.11 x M2x = and 2 1.16 y M2y = were obtained from Tm:YAP laser in continuous wave (CW) with the output power of 2W.
In this paper, we firstly demonstrate a diode-pumped passive mode-locking laser based on a Tm:YAG crystal and a MoS2 saturable absorber. The Tm:YAG laser produced a 2.68 W continuous-wave (CW) output power at 2013.8 nm. A maximum average output power of 0.2 W was achieved at a pulse repetition rate of 232.2 MHz and a pulse width of about 297.5 ps were achieved under the passive mode-locking operation. In addition, the M2 factors were 1.07 and 1.05 in horizontal and vertical directions, respectively, indicating the near-diffraction limited beam propagation.
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