SF_(6) has excellent insulation performance and arc extinguishing ability,and is widely used in the power industry.However,its global warming potential is about 23,500 times that of C0_(2),it can exist stably in the a...SF_(6) has excellent insulation performance and arc extinguishing ability,and is widely used in the power industry.However,its global warming potential is about 23,500 times that of C0_(2),it can exist stably in the atmosphere,it is not easily degradable and is of great potential harm to the environment.Based on pulsed dielectric barrier discharge plasma technology,the effects of H_(2)O and 0_(2) on the degradation of SF_(6) were studied.Studies have shown that H_(2)O can effectively promote the decomposition of SF_(6) and improve its degradation rate and energy efficiency of degradation.Under the action of a pulse input voltage and input frequency of 15 kV and 15 kHz,respectively,when H_(2)O is added alone the effect of 1% H_(2)O is the best,and the rate and energy efficiency of degradation of SF_(6) reach their maximum values,which are 91.9% and 8.25 g kWh^(-1),respectively.The synergistic effect of H_(2)O and O_(2) on the degradation of SF_(6) was similar to that of H_(2)O.When the concentration of H_(2)O and O_(2) was 1%,the system obtained the best rate and energy efficiency of degradation,namely 89.7% and 8.05 g kWh~(-1),respectively.At the same time,different external gases exhibit different capabilities to regulate decomposition products.The addition of H_(2)O can effectively improve the selectivity of S0_(2).Under the synergistic effect of H_(2)O and O_(2),with increase in O_(2) concentration the degradation products gradually transformed into SO_(2)F_(2).From the perspective of harmless treatment of the degradation products of SF_(6),the addition of O_(2) during the SF_(6) degradation process should be avoided.展开更多
Special interest in current interruptions is dedicated to the processes close to the current zero instant, the so-called interaction region, which determines the circuit breakers＇ performance. The quantities of inter...Special interest in current interruptions is dedicated to the processes close to the current zero instant, the so-called interaction region, which determines the circuit breakers＇ performance. The quantities of interest in this region are the distribution of temperature, density and pressure, velocity and gas mass flow along the electric arc axis, as well as the distribution of electric stress between contacts Calculation of steady SF_6 gas flow through the nozzle of a 420 kV circuit breaker at the current zero instant, for different arcing durations, was carried out using a commercial CFD （computational fluid dynamics） simulation tool. The calculation results were used to get insight into improvement possibilities of the SF_6 gas flow model used in the software for computer simulation of HV （high-voltage） circuit breakers. Electric field calculation results were performed for the same 420 kV circuit breaker, in order to estimate the breakdown voltage at the current zero instant.展开更多
基金supported by Guizhou Province (Ceneral), grant/award number Qian Ke He Zhi Cheng [2022] General 207, National Natural Science Foundation of China (No. 52307170)Natural Science Foundation of Hubei Province, China (No. 2023AFB382)。
文摘SF_(6) has excellent insulation performance and arc extinguishing ability,and is widely used in the power industry.However,its global warming potential is about 23,500 times that of C0_(2),it can exist stably in the atmosphere,it is not easily degradable and is of great potential harm to the environment.Based on pulsed dielectric barrier discharge plasma technology,the effects of H_(2)O and 0_(2) on the degradation of SF_(6) were studied.Studies have shown that H_(2)O can effectively promote the decomposition of SF_(6) and improve its degradation rate and energy efficiency of degradation.Under the action of a pulse input voltage and input frequency of 15 kV and 15 kHz,respectively,when H_(2)O is added alone the effect of 1% H_(2)O is the best,and the rate and energy efficiency of degradation of SF_(6) reach their maximum values,which are 91.9% and 8.25 g kWh^(-1),respectively.The synergistic effect of H_(2)O and O_(2) on the degradation of SF_(6) was similar to that of H_(2)O.When the concentration of H_(2)O and O_(2) was 1%,the system obtained the best rate and energy efficiency of degradation,namely 89.7% and 8.05 g kWh~(-1),respectively.At the same time,different external gases exhibit different capabilities to regulate decomposition products.The addition of H_(2)O can effectively improve the selectivity of S0_(2).Under the synergistic effect of H_(2)O and O_(2),with increase in O_(2) concentration the degradation products gradually transformed into SO_(2)F_(2).From the perspective of harmless treatment of the degradation products of SF_(6),the addition of O_(2) during the SF_(6) degradation process should be avoided.
文摘Special interest in current interruptions is dedicated to the processes close to the current zero instant, the so-called interaction region, which determines the circuit breakers＇ performance. The quantities of interest in this region are the distribution of temperature, density and pressure, velocity and gas mass flow along the electric arc axis, as well as the distribution of electric stress between contacts Calculation of steady SF_6 gas flow through the nozzle of a 420 kV circuit breaker at the current zero instant, for different arcing durations, was carried out using a commercial CFD （computational fluid dynamics） simulation tool. The calculation results were used to get insight into improvement possibilities of the SF_6 gas flow model used in the software for computer simulation of HV （high-voltage） circuit breakers. Electric field calculation results were performed for the same 420 kV circuit breaker, in order to estimate the breakdown voltage at the current zero instant.
文摘通过水热法结合高温固相法合成片状纳米MoS_(2)结构,并用场发射扫描电子显微镜(field emission scanning electron microscopy,FESEM)、X射线衍射(X-ray diffraction,XRD)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)与拉曼光谱对MoS_(2)微观形貌、晶体结构、元素组成与振动模式进行表征,将纳米MoS_(2)通过丝网印刷法均匀涂覆于叉指电极表面制备电阻式气体传感器,测试SO2、SOF2、SO2F2和H2S共4种SF_(6)分解特征组分的气敏响应特性,用第一性原理密度泛函理论,分析MoS_(2)微观结构的物理化学特性,探索SF_(6)分解组分别在MoS_(2)表面与边缘结构的吸附性能,包括吸附能、电荷转移、吸附距离与范德华力比率等。结果显示,基于片状纳米MoS_(2)的气体传感器对4种SF_(6)分解组分的最佳工作温度均为200℃。在最佳工作温度下,传感器对4种SF_(6)分解组分在0~50×10^(-6)响应–浓度关系有高线性度(R^(2)>0.959),理论检测极限排序为H_(2)S<SO_(2)<SOF_(2)<SO_(2)F_(2),大小分别为531×10^(-9)、622×10^(-9)、1.55×10^(-6)与2.89×10^(-6)。同时理论计算结果表明,MoS_(2)边缘结构对气敏响应贡献占主导作用,且对不同SF_(6)分解组分的不同灵敏度来源于分子与MoS_(2)边缘结构的不同化学相互作用能与电荷转移。该研究为基于过渡金属硫化物的气敏传感器(transition metal dichalcogenides,TMDCs)检测SF_(6)分解组分提供实验和理论支持。
