Characteristic Decomposition Components Research Articles

Study on Pd-MoTe2 monolayer for adsorption and sensing of air decomposition products in air-insulated switchgear

Detecting characteristic decomposition components has become a popular method for assessing the operational stability of air-insulated switchgear. This paper investigates the adsorption and sensing properties of a Pd-modified MoTe2 (Pd-MoTe2) for two common defective gases, namely, NO2 and CO, in air-insulated switchgear and employs the first-principles density functional theory (DFT) to conduct the analysis. According to the findings, Pd has a preference for doping in the TMo site on the MoTe2 monolayer, with a binding energy (Eb) of −2.240 eV. The Pd-MoTe2 monolayer exhibits effective adsorption of NO2 and CO, with both molecules chemisorbed. The adsorption energies (Ead) for NO2 and CO are −1.307 eV and −1.550 eV, respectively. Furthermore, there is an evident reduction of the band gap for the Pd-MoTe2 upon adsorbing NO2, decreasing the resistance value. In short, the Pd-MoTe2 monolayer has shown great promise as a gas sensor, laying the groundwork for improving power system stability.

The Adsorption Mechanisms of SF6-Decomposed Species on Tc- and Ru-Embedded Phthalocyanine Surfaces: A Density Functional Theory Study.

Designing high-performance materials for the detection or removal of toxic decomposition gases of sulfur hexafluoride is crucial for both environmental monitoring and human health preservation. Based on first-principles calculations, the adsorption performance and gas-sensing properties of unsubstituted phthalocyanine (H2Pc) and H2Pc doped with 4d transition metal atoms (TM = Tc and Ru) towards five characteristic decomposition components (HF, H2S, SO2, SOF2, and SO2F2) were simulated. The findings indicate that both the TcPc and RuPc monolayers are thermodynamically and dynamically stable. The analysis of the adsorption energy indicates that H2S, SO2, SOF2, and SO2F2 underwent chemisorption on the TcPc monolayer. Conversely, the HF molecules were physisorbed through interactions with H atoms. The chemical adsorption of H2S, SO2, and SOF2 occurred on the RuPc monolayer, while the physical adsorption of HF and SO2F2 molecules was observed. Moreover, the microcosmic mechanism of the gas-adsorbent interaction was elucidated by analyzing the charge density differences, electron density distributions, Hirshfeld charges, and density of states. The TcPc and RuPc monolayers exhibited excellent sensitivity towards H2S, SO2, and SOF2, as evidenced by the substantial alterations in the band gaps and work functions of the TcPc and RuPc nanosheets. Our calculations hold significant value for exploring the potential chemical sensing applications of TcPc and RuPc monolayers in gas sensing, with a specific focus on detecting sulfur hexafluoride.

First-principles investigation of Pt-doped MoTe2 for detecting characteristic air decomposition components in air insulation switchgear

Air-insulated switchgear plays a significant role in electrical engineering; the running stability of this equipment is required higher. In this work, the Pt-doped MoTe2 (Pt-MoTe2) monolayer is proposed as a novel sensing material for the detection of air decomposition components: NO2 and O3, to evaluate the operation status of air insulation switchgear. The Pt dopant is stably anchored on the MoTe2 surface with the binding force (Eb) of −3.02 eV, and the band gap decreases after Pt-doping on the pure MoTe2 monolayer. Besides, the Pt-MoTe2 monolayer behaves as chemisorption upon NO2 and O3 molecules adsorption with adsorption energy (Ead) of −1.750 eV, −2.045 eV, respectively. Furthermore, the NO2 and O3 molecules behave as electron-acceptor withdrawing charges from the Pt-MoTe2 monolayer, based on the Hirshfeld analysis. Comparing two gas systems, it is found that band gap decreases in both gas systems, and the degree of decrease varies significantly, which makes it possible to develop resistance-type gas sensor to detect NO2 and O3 molecules. Our calculations give an insight into the physicochemical property of Pt-MoTe2 monolayer, and elucidate their promising potential as novel gas sensors for air insulating switchgear.

Thermal Decomposition of Epoxy Resin Under SF6 Atmosphere

The latent fault diagnosis of GIS equipment relies on the electrothermal corrosion information of the decomposition products of SF6. The thermal decomposition of epoxy resin under atmosphere (SF6-Epoxy) is essential to reveal the relationship between carbon-based characteristic decomposition components and the degradation of insulating materials. The thermal decomposition process of SF6-Epoxy was measured using synchronous thermogravimetry(TG)/differential scanning calorimetry(DSC), which unveiled the three pyrolysis stages of temperature range and heat release. The online gas chromatography identified nine decomposition components containing carbon, sulfur and oxygen elements. According to the panoramic pyrolysis reaction mechanism of the SF6-epoxy system, CO2, CH4, SOF2, H2S and H2 were proposed as the characteristic decomposition components for the thermal deterioration of SF6-Epoxy insulating system.

First-Principles Investigation of Pt-Doped Mote2 for Detecting Characteristic Air Decomposition Components in Air Insulation Switchgear

First-Principles Investigation of Pt-Doped Mote2 for Detecting Characteristic Air Decomposition Components in Air Insulation Switchgear

Adsorption Properties of NF3 and N2O on Al- and Ga-Doped Graphene Surface: A Density Functional Theory Study

SF6/N2 gas mixture decomposition components can reflect the operation status inside GIS, and be used for fault diagnosis and monitoring inside GIS. NF3 and N2O are the characteristic decomposition components of SF6/N2 mixed gas. In order to find a potential gas sensitivity material for the detection of NF3 and N2O. This paper investigated the adsorption properties of NF3 and N2O on Al- and Ga- doped graphene monolayers based on density functional theory. Through the analysis of adsorption distance, charge transfer, adsorption energy, energy band structure, etc., the results indicated that the adsorption effect of Al- and Ga-doped graphene to NF3 and N2O are probably good, and these nanomaterials are potential to apply for the monitoring of GIS internal faults.

A local over-thermal fault evaluation method for C5F10O insulated power equipment based on DWT and BP neural network optimized by GA

Due to the growing problem of global warming, C5F10O is promising to replace SF6 as an insulation medium in power equipment because of its low global warming potential and excellent insulation performance and thus has a wide application prospect in the electrical engineering field. Local over-thermal fault is one of the most severe faults in power equipment and has a close relationship with the characteristic decomposition components (CDCs). This paper is devoted to proposing an evaluation method for local over-thermal fault by analyzing CDCs. The discrete wavelet transformation method was adopted to recognize CDC (CF2, CF2CF2, COCF2, and CFCF3) from their variation curves, and the fault feature vector was extracted based on the analysis of frequency band energy. The back propaganda neural network optimized by the genetic algorithm was employed to evaluate the severity of local over-thermal fault with a high accuracy. This work can lay a theoretical basis for local over-thermal fault evaluation based on CDCs in environmentally friendly power equipment.

SF6 Partial Discharge Decomposition Characteristics Under Different Lengths of Wire-Type Metal Particles in Direct Current Gas Insulated Equipment

Aiming at the serious defects of wire-type free metal particles, which can cause severe partial discharge (PD) in Direct current (DC) gas-insulated equipment, the experiments on the influence of four lengths (3.0, 5.0, 7.0, and 9.0 mm) of wire-type free metal materials on SF6 decomposition under DC PD were conducted. The formation rules of four characteristic decomposition components, namely, CF4, SOF2, SO2F2 and SO2, under different lengths of wire-type free metal particles, were determined using gas chromatography. Results showed that the amounts of four kinds of SF6 DC PD characteristic decomposition components are proportional to the length of wire-type free metal particles. The long length of wire-type free metal particles increases the intensity of PD and the amount and effective generation rates of SF6 DC PD characteristic decomposition components. All these findings provide an experimental basis for the diagnosis of insulation defect types in SF6 DC gas insulated equipment.

Study on ultraviolet absorption characteristics of SF6 decomposition components

Establish the UV spectrum database of the SF6 characteristic decomposition components: Based on the previous research and simulation analysis, obtain the UV spectrum of the SF6 characteristic decomposition components, and establish the corresponding database. Through the analysis of a large number of actual test data, the ultraviolet spectrum database of SO2, CS2 and H2S is obtained and established to realize the quantitative analysis of SO2, CS2 and H2S. The detection accuracy of H2S and the SO2 reaches 10−6 level, and that of the CS2 reaches 10−9 level, realizing the low concentration quantitative detection of SF6 characteristic components. The detection of SO2, CS2 and H2S in gas insulated equipment can effectively predict and diagnose the occurrence of partial discharge fault, partial overheating fault and solid insulation fault in gas insulated equipment. As the symbol gas, the generation of H2S directly indicates the occurrence of more serious partial overheating or partial discharge fault, while SO2 is the characteristic component gas. The occurrence of CS2 indicates that there may be a local fault involving solid insulating medium in the equipment. The detection of three gases can provide important conditions for on-line monitoring of gas insulated equipment.

Decomposition Characteristics of SF6/N2 Under Partial Discharge of Different Degrees

SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas mixture can not only reduce the consumption of SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> in power system, but also effectively alleviate SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> greenhouse effect. Since SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> can decompose under the alternating current partial discharge(PD), its decomposition characteristics are closely related to PD attributes. Therefore, the fault diagnosis method can be established through its PD decomposition characteristics. However, at present, the decomposition characteristics of SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixed gas under PD have not been fully grasped, and the correlation characteristics between decomposition characteristics and PD intensity have not been obtained. To this end, this article uses pin-plate electrodes to simulate the typical metal protrusion insulation defects in GIS equipment. SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> decomposition experiments are conducted at different PD intensity to study the correlation between the PD decomposition characteristics of SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixed gas and PD intensity. The results show that: the generation rate of characteristic decomposition components such as SOF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , SOF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , NO, NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , and NF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> are positively correlated with PD intensity; NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and (SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> +SOF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> +SOF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> +SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) can be used as the characteristic quantity to judge the whole process of PD, SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> can be used as the feature to judge the early PD, and SOF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and SOF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> can be used as the features to judge the severe PD. The results of this article will lay the foundation for the monitoring of equipment insulation status using SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> decomposition characteristics in the future.

First-principles study of Pd-MoSe2 as sensing material for characteristic SF6 decomposition components

SF6 decomposition component detection is an effective way to diagnose the severity and type of electric discharge. In this study, MoSe2 based material has been chosen as the gas sensing material for the detection of SOF2 and SO2F2, the two characteristic decomposition components of SF6. Based on density functional theory calculations, the adsorption properties of both SOF2 and SO2F2 on intrinsic and Pd doped MoSe2 are studied by analyzing the adsorption structure, charge transfer, density of states, and molecular orbit. The results show that SOF2 and SO2F2 adsorb on intrinsic MoSe2 by physisorption, resulting in weak gas sensitivity. After Pd doping on MoSe2, it dramatically enhances the gas sensitivity of MoSe2 to SOF2 and SO2F2; both the gases interact with Pd-MoSe2 by chemisorption. In addition, SOF2 and SO2F2 show an increase in conductivity during the adsorption process to different extents. The calculation results show that Pd-MoSe2 can be a potential gas sensing material for SOF2 and SO2F2 detection in SF6-insulated equipment.

Thermal Decomposition Properties of Epoxy Resin in SF₆/N₂ Mixture.

As a promising alternative for pure SF6, the mixture of SF6/N2 appears to be more economic and environment-friendly on the premise of maintaining similar dielectric properties with pure SF6. But less attention has been paid to the thermal properties of an SF6/N2 mixture, especially with insulation materials overheating happening simultaneously. In this paper, thermal decomposition properties of epoxy resin in SF6/N2 mixture with different SF6 volume rates were studied, and the concentrations of characteristic decomposition components were detected based on concentrations change of some characteristic gas components such as CO2, SO2, H2S, SOF2, and CF4. The results showed that thermal properties of 20% SF6/N2 (volume fraction of SF6 is 20%) mixture has faster degradation than 40% SF6/N2 mixture. As ratio of SF6 content decreases, thermal stability of the system decreases, and the decomposition process of SF6 is exacerbated. Moreover, a mathematical model was established to determine happening of partial overheating faults on the epoxy resin surface in SF6/N2 mixture. Also thermal decomposition process of epoxy resin was simulated by the ReaxFF force field to reveal basic chemical reactions in terms of bond-breaking order, which further verified that CO2 and H2O produced during thermal decomposition of epoxy resin can intensify degradation of SF6 dielectric property.

SF 6 positive DC partial discharge decomposition components under four typical insulation defects

The condition monitoring and fault diagnosis method based on decomposed component analysis (DCA) for SF6 gas-insulated equipment, which mainly aiming at AC SF6 gas-insulated equipment, has become a research hotspot. Therefore, SF6 positive DC partial discharge (PD) decomposition experiments under four typical insulation defects were conducted in this work. The result showed that there is a significant correlation between the generation rules of the five SF6 decomposition components (CF4, CO2, SO2F2, SOF2 and SO2) and the types of defects. The phenomenon was attributed to the variations in the properties of the four insulation defects. In addition, comparing with AC PD experiment, for the protrusion, contamination and gap defect models, the amounts and generation rates of the five characteristic decomposition components under positive DC are less than those under AC by the same defect; however, for the particles defect, it is by contrary. This could be attributed to the essential difference between AC PD and positive DC PD. Therefore, the theory of AC DCA could provide reference to construct DCA diagnostic model for DC SF6 gas-insulated equipment, but cannot be applied mechanically.

SF6 decomposition components under different metallic free‐conducting wire‐type particles in positive DC partial discharge

AbstractThis study aimed to explore the common free‐conducting wire‐type particles that can produce severe partial discharge (PD) in DC gas‐insulated equipment. The experiment was conducted on the SF6 positive DC PD experimental system to determine the influence of the free‐conducting wire‐type particles of three kinds of metal materials (aluminum, 18/8 stainless steel, and copper) on SF6 decomposition. The change rules of five main characteristic decomposition components, namely, CF4, CO2, SOF2, SO2F2, and SO2, under different free‐conducting metal particles were obtained using gas chromatography–mass spectrometry quantitative detection. No significant correlation was observed between the formation of CO2 and the kinds of metal materials; however, the kinds of metal materials significantly influenced the formation of the other four kinds of characteristic gases. The differences in the physical and chemical properties of the metal materials caused the different characteristics of SF6 positive DC PD decomposition under different free‐conducting metal wire‐type particles. Findings provide an experimental basis for the diagnosis of fault‐type positive DC SF6 gas‐insulated equipment. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley &amp; Sons, Inc.

Adsorption of SF6 decomposition components on Pt3-TiO2(1 0 1) surface: A DFT study

SF6 decomposition components detection plays an important role in diagnosing and evaluating the electric discharge faults in SF6-insulated equipment. In this paper, Pt3-supported TiO2(1 0 1) was used to study the influence of the Pt clusters modification on the gas sensing property of TiO2(1 0 1) material to the characteristic decomposition components of SF6: H2S, SO2, SOF2 and SO2F2. The theoretical calculation results show that the intrinsic TiO2(1 0 1) only shows adsorption performance to H2S. Due to the strong chemical activity of Pt3, it significantly increases the electrical conductivity and gas sensing properties of TiO2(1 0 1). SF6 decomposition components adsorption decreases the electrical conductivity of the adsorption system. According to the different change degrees of electrical conductivity, it can be used to recognize the type and concentration of each SF6 decomposition component. By building the relationship between the type and concentration of SF6 decomposition components, and the type and severity of discharge faults, it provides an effective online way to diagnose and evaluate the discharge faults in SF6-insulated equipment.

Influence and mechanism of pressure on SF6 decomposition components of gas‐insulated switchgear under positive DC partial discharge

To clarify the influence of pressure on SF6 decomposition under positive DC partial discharge (PD), SF6‐positive DC partial discharge decomposition experiments at different pressures were carried out. We found that the contents of SF6 primary decomposition products are proportional to . Keeping the chamber volume and external temperature constant, the difference of air chamber pressure means that the electronic mean free path is different. So, different pressures make a difference in the energy of free electrons obtained in a single flight, which results in the difference in the reaction rates of SF6 primary decomposition and further influences the formation of SF6 PD characteristic decomposition components. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley &amp; Sons, Inc.

Study on the Characteristic Decomposition Components of DC SF6-Insulated Equipment under Positive DC Partial Discharge

Pulses with different amplitudes occur when an inner partial discharge fault exists in SF6-gas-insulated DC high-voltage electrical equipment. SF6 decomposes following complex physical and chemical processes. Discussing and quantifying the mathematical relationship of pulse discharge quantities to SF6 decomposition component characteristics is helpful to evaluate and predict the insulation fault severity and development trends in SF6-insulated DC equipment. Numerous simulation experiments on SF6 decomposition under positive DC partial discharge were performed on a needle-plane model. The DC partial discharge quantities of pulses are obtained, and decomposition characteristics based on the mechanism of SF6 decomposition are analyzed. Results show that generation, effective generation rate and concentration ratio c(SO2F2 + SOF4)/c(SOF2 + SO2) of components increase with partial discharge severity, and the first two act in the following order: SOF4 &gt; SOF2 &gt; SO2F2 &gt; SO2 &gt; CF4 when the discharge quantity level is higher than 238,957 pC. Finally, a coefficient matrix illustrates the mathematical effects of pulses with different discharge quantities on different SF6 decomposition components. The pulses whose discharge quantity is higher than 50 pC have obvious promotion effects on the formation of decomposition components, whereas the pulses whose discharge quantity lower than 50 pC decrease the positive promotion effects that large discharge pulses have on decomposition components. The higher the effective generation rates are, the greater the partial discharge severity is, and their change laws provide a new method to evaluate and predict insulation fault severity and development trends in DC SF6-insulated equipment with high reliability and detection stability.

Influence of humidity and voltage on characteristic decomposition components under needle-plate discharge model

Detecting the decomposition components in air-insulated switchgear is an effective method to evaluate the discharge severity of air-insulated switchgear. Experimental and theoretical studies are conducted to investigate the types of decomposition components and generation mechanism under the partial and disruptive discharge conditions. The discharge experiments use a needle–plate discharge tank, and the effect of relative humidity (50, 70 and 90%) and voltage (6, 6.5, 7 and 7.5 kV) are studied in detail. Considering the partial discharge process, the concentrations of CO and NO2 increase with the applied voltage and partial discharge time. The CO concentration increases with the increase of humidity, while NO2 concentration shows the reverse change trend. During the disruptive discharge process, the decomposition component NO increases with humidity. The dissipation of these decomposition components is also investigated using experiment. The small part of CO dissipation is from the adsorption with H2O molecules and onto the surface of discharge tank. The reaction between NO and O free radical, O2 and O3 consumes the concentration of NO and produces NO2. And the reaction between NO2 and H2O consumes most of the generated NO2 in the discharge tank. In the theoretical research, the reaction energy of CO, NO and NO2 generation is computed to analyze the generation and dissipation mechanism of decomposition components using Materials Studio.

Study on the characteristic decomposition components of air-insulated switchgear cabinet under partial discharge

Air-insulated switchgear cabinet plays a critical role in entire power transmission and distribution system. Its stability directly affects the operational reliability of the power system. And the on-line gas detection method, which evaluates the insulation status of insulation equipment by detecting the decomposition components of filled air in cabinet, becomes an innovative way to ensure the running stability of air-insulated switchgear cabinet. In order to study the characteristic gas types and production regularity of decomposition components under partial discharge, three insulation defects: needle-plate, air-gap and impurity defect are proposed to simulate the insulation defects under partial discharge in air-insulated switchgear cabinet. Firstly, the generation pathways and mechanism of composition components are discussed. Then CO and NO2 are selected as the characteristic decomposition components to characterize the partial discharge due to their high concentration and chemical stability. Based on the different change regularity of CO and NO2 concentration under different insulation defect, it provides an effective way to evaluate and predict the insulation defect type and severity in the field.

Adsorptions of SO2, SOF2, and SO2F2 on Pt-modified anatase (1 0 1) surface: Sensing mechanism study

The type and severity of faults occurring in gas-insulated switchgear (GIS) can be assessed by detecting SF6 decomposed gases, which is significant for fault diagnosis and online condition monitoring of GIS. Characteristic decomposition components of SF6 under partial discharge or overheating faults and first-principle density functional theory calculations are adopted to analyze the adsorption of SO2, SOF2, and SO2F2 on Pt-modified anatase (101) surface and to examine further the sensing mechanism of Pt-modified anatase-based gas sensor used to detect SO2, SOF2, and SO2F2. Results show that SO2F2 molecule more easily decomposes upon adsorption on the active Pt nanoparticle than SOF2 molecule. Meanwhile, SO2 molecule does not decompose. This finding explains the phenomenon in the sensing experiment of Pt-modified TiO2 nanotube array gas sensor, wherein the response of SO2F2 is higher than that of SOF2 at the optimal temperature of the sensor. Moreover, the responses of SO2F2 and SOF2 significantly change at the optimal temperature, whereas the response of SO2 is nearly unchanged.