Abstract: The present invention is a method for preventing copper sulfide generation in oil-filled electrical equipment having an inhibitor of copper sulfide generation in insulating oil, and the method is characterized in monitoring characteristics of the insulating oil and performing re-addition of the inhibitor at an appropriate moment in accordance with a result of the monitoring.

Abstract: The present invention relates to an electric insulating oil inspection method for determining whether or not an inhibitor-consuming substance is present in an electric insulating oil. The inhibitor-consuming substance is such a substance that causes to decrease over time a concentration of an inhibitor which is added to the electric insulating oil to inhibit copper sulfide from being generated on an insulating paper immersed in the electric insulating oil. The electric insulting oil inspection method includes steps of: preserving the electric insulating oil at a predetermined condition, measuring a concentration of the inhibitor, and determining that the inhibitor-consuming substance is present upon condition that a decrement of the concentration of the inhibitor relative to an initial concentration of the inhibitor becomes not less than a specified amount within a predetermined period.

Abstract: The present invention is a diagnosing method for oil-filled electrical equipment for diagnosing a degree of risk with regard to occurrence of abnormality due to copper sulfide generation in oil-filled electrical equipment, and the method includes a first step of detecting specific compounds contained in insulating oil in said oil-filled electrical equipment, a second step of evaluating a possibility of copper sulfide generation at a dangerous part leading to dielectric breakdown in said oil-filled electrical equipment in accordance with a detection result obtained in said first step, and a third step of diagnosing a degree of risk with regard to occurrence of abnormality in said oil-filled electrical equipment in accordance with an evaluation result obtained in said second step. Said specific compounds include dibenzyldisulfide and 2,6-di-t-butyl-p-cresol.

Abstract: An object of the invention is to provide a diagnostic method for an oil-filled electrical device that considers a temperature distribution in the oil-filled electrical device and enables accurate diagnosis to be conducted even when the method is applied to diagnosis of an actually operating device, and further provide a method with which such diagnosis of an oil-filled electrical device can be conducted from a component analysis value of an insulating oil in the oil-filled electrical device. The invention is a diagnostic method for an oil-filled electrical device including in an insulating oil a metal part wrapped with insulating paper, and determines that a time when a surface resistivity of a maximum precipitation site where metal sulfide is most precipitated on the insulating paper reaches a preset surface resistivity management value is a time of occurrence of an abnormality.

Abstract: The present invention is a method for preventing copper sulfide generation in oil-filled electrical equipment having an inhibitor of copper sulfide generation in insulating oil, and the method is characterized in monitoring characteristics of said insulating oil and performing re-addition of said inhibitor at an appropriate moment in accordance with a result of said monitoring.

Abstract: The present invention provides a method for inhibiting production of copper sulfide in an electrical insulating oil inside an oil-filled electrical apparatus, including adding a benzotriazole compound not having a long-chain alkyl group when the oil-filled electrical apparatus is an open-type oil-filled electrical apparatus, or adding a benzotriazole compound having a long-chain alkyl group when the oil-filled electrical apparatus is a closed-type oil-filled electrical apparatus.

Abstract: The present invention provides a method for inhibiting production of copper sulfide in an electrical insulating oil inside an oil-filled electrical apparatus, including adding a benzotriazole compound not having a long-chain alkyl group when the oil-filled electrical apparatus is an open-type oil-filled electrical apparatus, or adding a benzotriazole compound having a long-chain alkyl group when the oil-filled electrical apparatus is a closed-type oil-filled electrical apparatus.

Abstract: The present invention relates to an electric insulating oil inspection method for determining whether or not an inhibitor-consuming substance is present in an electric insulating oil. The inhibitor-consuming substance is such a substance that causes to decrease over time a concentration of an inhibitor which is added to the electric insulating oil to inhibit copper sulfide from being generated on an insulating paper immersed in the electric insulating oil. The electric insulting oil inspection method includes steps of: preserving the electric insulating oil at a predetermined condition, measuring a concentration of the inhibitor, and determining that the inhibitor-consuming substance is present upon condition that a decrement of the concentration of the inhibitor relative to an initial concentration of the inhibitor becomes not less than a specified amount within a predetermined period.

Abstract: An initial concentration of the residual concentration of a causative substance contained in an insulating oil is compared with a reference value. The causative substance reacts with a conductor forming a winding of an oil-filled electrical device to generate an electrically conductive compound. The reference value is defined as a value for determining whether a main determinant that determines the lifetime of the oil-filled electrical device is generation of the electrically conductive compound or degradation of insulating paper. Based on the initial concentration of the causative substance and the reference value, the lifetime of the oil-filled electrical device is assessed.

Abstract: Provided is a diagnosis method for an oil-filled electrical apparatus, which is for evaluating the degree of danger of copper sulfide being generated within the oil-filled electrical apparatus, comprising: a first step for detecting a specific compound contained within insulating oil inside the oil-filled electrical apparatus; a second step for evaluating the possibility of copper sulfide being generated inside the oil-filled electrical apparatus, on the basis of the result detected by the first step; and a third step for diagnosing the degree of danger of a malfunction occurring in the oil-filled electrical apparatus, on the basis of the evaluation result obtained in the second step. The specific compound contains dibenzyl disulfide and/or a reaction product of a radical resulting from dibenzyl disulfide, and di-tert-butyl-p-cresol and/or a reaction product of a radical resulting from di-tert-butyl-p-cresol, or, di-tert-butyl-phenol and/or a reaction product of a radical resulting from di-tert-butyl-phenol.

Abstract: In a gas insulated breaking device which accommodates open/close elements including a puffer cylinder which compresses an insulation gas and extinguishes an arc and a contact finger which has a slide contact portion which is brought into slide contact with a slide contact portion of the puffer cylinder in the inside of a vessel in which the insulation gas is sealed, a relatively soft plating film is formed on the slide contact portion of the puffer cylinder, and a relatively hard plating film is formed on the slide contact portion of the contact finger, and the silver plating film of each slide contact portion has an inner layer thereof formed of a soft film and an outer layer thereof which constitutes a surface portion formed of a hard film.

Abstract: An oil immersed electrical apparatus such as an oil immersed transformer that can detect copper sulfide precipitated on coil insulating paper is provided. In the oil immersed transformer in which a coil with its surface covered by insulating paper is arranged in a container filled with insulating oil, a detection member is prepared by providing two electrodes on a surface of a plate-like pressboard formed of cellulose, which is a same material as that of the insulating paper, this detection member is arranged in contact with the insulating oil, and generation of copper sulfide is detected from reduction in a surface resistance between the electrodes. The temperature of the detection member is set higher than the temperature of the coil so that copper sulfide is generated thereon prior to generation of copper sulfide on a coil unit.

Abstract: The present invention is a method of predicting the probability of abnormality occurrence in an oil-filled electrical device, including the steps of: measuring a residual dibenzyl disulfide concentration in an insulating oil sampled from an oil-filled electrical device in operation; determining an estimated decrease of the residual dibenzyl disulfide concentration, relative to an initial dibenzyl disulfide concentration at the start of operation of the oil-filled electrical device; calculating the initial dibenzyl disulfide concentration from the residual dibenzyl disulfide concentration and the estimated decrease; and comparing the initial dibenzyl disulfide concentration with a specific management value.

Abstract: In a gas insulated breaking device which accommodates open/close elements including a puffer cylinder which compresses an insulation gas and extinguishes an arc and a contact finger which has a slide contact portion which is brought into slide contact with a slide contact portion of the puffer cylinder in the inside of a vessel in which the insulation gas is sealed, a relatively soft plating film is formed on the slide contact portion of the puffer cylinder, and a relatively hard plating film is formed on the slide contact portion of the contact finger, and the silver plating film of each slide contact portion has an inner layer thereof formed of a soft film and an outer layer thereof which constitutes a surface portion formed of a hard film.

Abstract: An initial concentration of the residual concentration of a causative substance contained in an insulating oil is compared with a reference value. The causative substance reacts with a conductor forming a winding of an oil-filled electrical device to generate an electrically conductive compound. The reference value is defined as a value for determining whether a main determinant that determines the lifetime of the oil-filled electrical device is generation of the electrically conductive compound or degradation of insulating paper. Based on the initial concentration of the causative substance and the reference value, the lifetime of the oil-filled electrical device is assessed.

Abstract: An oil immersed electrical apparatus such as an oil immersed transformer that can detect copper sulfide precipitated on coil insulating paper is provided. In the oil immersed transformer in which a coil with its surface covered by insulating paper is arranged in a container filled with insulating oil, a detection member is prepared by providing two electrodes on a surface of a plate-like pressboard formed of cellulose, which is a same material as that of the insulating paper, this detection member is arranged in contact with the insulating oil, and generation of copper sulfide is detected from reduction in a surface resistance between the electrodes. The temperature of the detection member is set higher than the temperature of the coil so that copper sulfide is generated thereon prior to generation of copper sulfide on a coil unit.

Abstract: An object of the invention is to provide a diagnostic method for an oil-filled electrical device that considers a temperature distribution in the oil-filled electrical device and enables accurate diagnosis to be conducted even when the method is applied to diagnosis of an actually operating device, and further provide a method with which such diagnosis of an oil-filled electrical device can be conducted from a component analysis value of an insulating oil in the oil-filled electrical device. The invention is a diagnostic method for an oil-filled electrical device including in an insulating oil a metal part wrapped with insulating paper, and determines that a time when a surface resistivity of a maximum precipitation site where metal sulfide is most precipitated on the insulating paper reaches a preset surface resistivity management value is a time of occurrence of an abnormality.

Abstract: A gas-insulated equipment such as a gas-insulated switchgear provided according to the invention can efficiently improve dielectric strength of an entire electrode system considering electric field distribution of the electrodes and conductors and improving insulation coordination so that miniaturization of the entire device can be achieved. The gas-insulated switchgear includes insulating gas sealed within an earth metal container and an insulating spacer insulating and supporting high-voltage receiving portions. Surfaces of shielding electrodes having a larger diameter than that of high-voltage conductors are covered with thick dielectric coatings, and surfaces of the high-voltage conductors are covered with thin dielectric coatings.

Abstract: A gas-insulated equipment such as a gas-insulated switchgear provided according to the invention can efficiently improve dielectric strength of an entire electrode system considering electric field distribution of the electrodes and conductors and improving insulation coordination so that miniaturization of the entire device can be achieved. The gas-insulated switchgear includes insulating gas sealed within an earth metal container and an insulating spacer insulating and supporting high-voltage receiving portions. Surfaces of shielding electrodes having a larger diameter than that of high-voltage conductors are covered with thick dielectric coatings, and surfaces of the high-voltage conductors are covered with thin dielectric coatings.

Abstract: A gas-insulated equipment such as a gas-insulated switchgear provided according to the invention can efficiently improve dielectric strength of an entire electrode system considering electric field distribution of the electrodes and conductors and improving insulation coordination so that miniaturization of the entire device can be achieved. The gas-insulated switchgear includes insulating gas sealed within an earth metal container and an insulating spacer insulating and supporting high-voltage receiving portions. Surfaces of shielding electrodes having a larger diameter than that of high-voltage conductors are covered with thick dielectric coatings, and surfaces of the high-voltage conductors are covered with thin dielectric coatings.