Abstract: A connection sleeve connects two wire end portions adjacent to each other in an axial direction of a center axis, among wire end portions of flat-type wires that constitute each of a plurality of disc-shaped windings. A through hole allows the flat-type wire to be inserted from both sides. A pair of pressed portions sandwich the flat-type wire inserted in the through hole therebetween. At least one of a pair of end portions has a slit that divides an end surface when viewed from the direction in which a pair of end portions are aligned.

Abstract: A gas-insulated electric apparatus includes: a sealed container made of metal; a high-voltage conductor, housed within the sealed container, that receives voltage; an insulating support member that insulates the high-voltage conductor from the sealed container and support the high-voltage conductor to the sealed container; and a nonlinear-resistance film covering at least a portion of an inner surface of the sealed container, the portion being on a lower side of the inner surface with respect to the high-voltage conductor. The nonlinear-resistance film is formed by particles of a nonlinear-resistance material and an insulating material, and the particles of the nonlinear-resistance material are dispersed in the insulating material. The particles of the nonlinear-resistance material are placed in the insulating material such that one or more of the particles of the nonlinear-resistance material is in constant contact with a conductive foreign object trapped inside the sealed container.

Abstract: A gas-insulated electrical equipment includes: a grounded tank filled with an insulating gas; a central conductor which is disposed inside the grounded tank and to which to apply a voltage; a high-resistance insulating portion which is disposed on an inner surface of the grounded tank and which is configured of an insulating material of high resistivity; a low-resistance insulating portion which is disposed on at least a partial front surface of the high-resistance insulating portion and which has a resistivity lower than that of the high-resistance insulating portion, and a non-linear resistance insulating portion which is disposed on at least a partial front surface of the low-resistance insulating portion and which is configured of a non-linear resistance material, which exhibits a non-linear resistivity relative to a change in electric field, and an insulating material of high resistivity, wherein the low-resistance insulating portion has a floating potential.

Abstract: A stationary induction apparatus includes a core, a first winding, a second winding, and an insulating structure arranged between facing surfaces of the first winding and the second winding. The insulating structure is located between the facing surfaces of the first winding and the second winding. The insulating structure includes a first insulator having a cylindrical shape with the core as its central axis, and first insulating spacers arranged between the first winding and the first insulator and between the second winding and the first insulator. The first insulator includes a first nonlinear resistive layer containing a nonlinear resistive material having a nonlinear volume resistivity that decreases when an electric field is higher than a threshold. The first nonlinear resistive layer is provided in a portion of the first insulator which is at least in contact with one of the first insulating spacers.

Abstract: A gas-insulated electric apparatus includes: a sealed container made of metal; a high-voltage conductor, housed within the sealed container, that receives voltage; an insulating support member that insulates the high-voltage conductor from the sealed container and support the high-voltage conductor to the sealed container; and a nonlinear-resistance film covering at least a portion of an inner surface of the sealed container, the portion being on a lower side of the inner surface with respect to the high-voltage conductor. The nonlinear-resistance film is formed by particles of a nonlinear-resistance material and an insulating material, and the particles of the nonlinear-resistance material are dispersed in the insulating material. The particles of the nonlinear-resistance material are placed in the insulating material such that one or more of the particles of the nonlinear-resistance material is in constant contact with a conductive foreign object trapped inside the sealed container.

Abstract: A gas-insulated electrical equipment includes: a grounded tank filled with an insulating gas; a central conductor which is disposed inside the grounded tank and to which to apply a voltage; a high-resistance insulating portion which is disposed on an inner surface of the grounded tank and which is configured of an insulating material of high resistivity; a low-resistance insulating portion which is disposed on at least a partial front surface of the high-resistance insulating portion and which has a resistivity lower than that of the high-resistance insulating portion, and a non-linear resistance insulating portion which is disposed on at least a partial front surface of the low-resistance insulating portion and which is configured of a non-linear resistance material, which exhibits a non-linear resistivity relative to a change in electric field, and an insulating material of high resistivity, wherein the low-resistance insulating portion has a floating potential.

Abstract: A stationary induction apparatus includes a core, a winding wound around the core such that the core serves as a central axis, and an annular electrostatic shield disposed adjacent to at least one of ends of the winding in a direction along the central axis. The electrostatic shield includes a conductor and a second insulating coating that coats the conductor. The electrostatic shield has a potential lower than a highest potential in the winding.

Abstract: A plurality of windings each including an electric wire portion and a first insulating coating that coats the electric wire portion. A plurality of electrostatic shields each including a conductor and a second insulating coating that coats the conductor. A stationary induction apparatus satisfies at least one positional relationship among: a relationship in which an outer peripheral end of the conductor in each of the electrostatic shields is located inside an outer peripheral end of the electric wire portion of an adjacent winding among the windings, the adjacent winding being adjacent to the electrostatic shield in the direction extending along the central axis; and a relationship in which an inner peripheral end of the conductor in each of the electrostatic shields is located outside an inner peripheral end of the electric wire portion of the adjacent winding.

Abstract: A partial discharge determination method and apparatus, and a partial discharge determination system capable of indicating how much margin is left before dielectric breakdown, in a lighting impulse withstand voltage test, and a power device for which whether partial discharge is caused is determined by them, and a method for manufacturing a power device including the partial discharge determination method. A low-pass filter receives an acoustic signal resulting from application of an impulse voltage and acquired by an acoustic emission sensor, and removes an electromagnetic noise superimposed on the acoustic signal. A mechanical oscillation removal unit removes a mechanical oscillation component of a device under test, from the acoustic signal resulting from application of the impulse voltage which is a high voltage, based on the mechanical oscillation component acquired in advance and included in the acoustic signal resulting from application of the impulse voltage which is a low voltage.

Abstract: A stationary induction apparatus includes a core, a first winding, a second winding, and an insulating structure arranged between facing surfaces of the first winding and the second winding. The insulating structure is located between the facing surfaces of the first winding and the second winding. The insulating structure includes a first insulator having a cylindrical shape with the core as its central axis, and first insulating spacers arranged between the first winding and the first insulator and between the second winding and the first insulator. The first insulator includes a first nonlinear resistive layer containing a nonlinear resistive material having a nonlinear volume resistivity that decreases when an electric field is higher than a threshold. The first nonlinear resistive layer is provided in a portion of the first insulator which is at least in contact with one of the first insulating spacers.

Abstract: A gas-insulated electrical device includes a covering film covering an inner surface of a ground tank filled with an insulation gas. The covering film is formed of an insulation dielectric covering film that becomes more positively charged than metals in a triboelectric series, and becomes positively charged upon contact with metal foreign matter. At the same time, the metal foreign matter becomes negatively charged upon contact with the covering film. In a case where the high-voltage conductor is charged to a negative polarity, a Coulomb's force acts on the metal foreign matter in contact with the covering film in a direction away from the high-voltage conductor. The metal foreign matter in the ground tank is thus suppressed from floating.

Abstract: A gas-insulated switchgear includes a grounded tank filled with insulation gas, a center conductor which is disposed in the grounded tank and to which a voltage is applied, an insulating support member which insulates and supports the center conductor, and a nonlinear resistive part disposed at least on a vertically lower side inner surface of the grounded tank and formed by an insulation material containing a nonlinear resistive material. If an electric field applied to the nonlinear resistive part is higher than an electric field value in a vicinity of a contact point between the nonlinear resistive part and a metallic foreign substance mixed in the grounded tank during an operation, a resistivity of the nonlinear resistive part at the center conductor side is lower than a resistivity at which a discharge delay time is equal to an electric field relaxation time constant.

Abstract: A non-linear resistance film including an insulating material and a non-linear resistance material is provided on an inner surface of a grounded tank. The non-linear resistance film is formed to contain a larger amount of the non-linear resistance material on a side of a central conductor than on a side of the grounded tank. Accordingly, a gas insulated switchgear that can suppress partial discharge around metallic foreign matters and also can suppress inflow of charges from the grounded tank to the metallic foreign matters can be provided.

Abstract: A stationary induction apparatus includes a core, a winding wound around the core such that the core serves as a central axis, and an annular electrostatic shield disposed adjacent to at least one of ends of the winding in a direction along the central axis. The electrostatic shield includes a conductor and a second insulating coating that coats the conductor. The electrostatic shield has a potential lower than a highest potential in the winding.

Abstract: A plurality of windings each including an electric wire portion and a first insulating coating that coats the electric wire portion. A plurality of electrostatic shields each including a conductor and a second insulating coating that coats the conductor. A stationary induction apparatus satisfies at least one positional relationship among: a relationship in which an outer peripheral end of the conductor in each of the electrostatic shields is located inside an outer peripheral end of the electric wire portion of an adjacent winding among the windings, the adjacent winding being adjacent to the electrostatic shield in the direction extending along the central axis; and a relationship in which an inner peripheral end of the conductor in each of the electrostatic shields is located outside an inner peripheral end of the electric wire portion of the adjacent winding.

Abstract: A partial discharge determination method and apparatus, and a partial discharge determination system capable of indicating how much margin is left before dielectric breakdown, in a lighting impulse withstand voltage test, and a power device for which whether partial discharge is caused is determined by them, and a method for manufacturing a power device including the partial discharge determination method. A low-pass filter receives an acoustic signal resulting from application of an impulse voltage and acquired by an acoustic emission sensor, and removes an electromagnetic noise superimposed on the acoustic signal. A mechanical oscillation removal unit removes a mechanical oscillation component of a device under test, from the acoustic signal resulting from application of the impulse voltage which is a high voltage, based on the mechanical oscillation component acquired in advance and included in the acoustic signal resulting from application of the impulse voltage which is a low voltage.

Abstract: Each of a plurality of electrostatic shields includes an insulator portion and a conductor portion. The conductor portion includes a flat portion formed in an annular shape and a pair of protruding portions. The insulator portion is provided with a first housing portion housing the flat portion and a pair of second housing portions each housing a corresponding one of the pair of protruding portions. Each of the pair of protruding portions includes: a protruding end portion located along an inner surface of a corresponding one of the pair of second housing portions, and a center portion located adjacent to the protruding end portion. In each of the pair of protruding portions, the protruding end portion and the center portion are electrically connected to each other and are equal in electric potential to each other.

Abstract: A gas-insulated switchgear includes a grounded tank filled with insulation gas, a center conductor which is disposed in the grounded tank and to which a voltage is applied, an insulating support member which insulates and supports the center conductor, and a nonlinear resistive part disposed at least on a vertically lower side inner surface of the grounded tank and formed by an insulation material containing a nonlinear resistive material. If an electric field applied to the nonlinear resistive part is higher than an electric field value in a vicinity of a contact point between the nonlinear resistive part and a metallic foreign substance mixed in the grounded tank during an operation, a resistivity of the nonlinear resistive part at the center conductor side is lower than a resistivity at which a discharge delay time is equal to an electric field relaxation time constant.

Abstract: Each of a plurality of electrostatic shields includes an insulator portion and a conductor portion. The conductor portion includes a flat portion formed in an annular shape and a pair of protruding portions. The insulator portion is provided with a first housing portion housing the flat portion and a pair of second housing portions each housing a corresponding one of the pair of protruding portions. Each of the pair of protruding portions includes: a protruding end portion located along an inner surface of a corresponding one of the pair of second housing portions, and a center portion located adjacent to the protruding end portion. In each of the pair of protruding portions, the protruding end portion and the center portion are electrically connected to each other and are equal in electric potential to each other.

Abstract: A non-linear resistance film including an insulating material and a non-linear resistance material is provided on an inner surface of a grounded tank. The non-linear resistance film is formed to contain a larger amount of the non-linear resistance material on a side of a central conductor than on a side of the grounded tank. Accordingly, a gas insulated switchgear that can suppress partial discharge around metallic foreign matters and also can suppress inflow of charges from the grounded tank to the metallic foreign matters can be provided.