COMBINED ELECTRIC APPLIANCE WITH MULTI-CAPACITIVE SCREEN INSULATION CORE

Abstract

A combined electric appliance with a multi-capacitive screen insulation core has three groups of capacitive screens of main capacitor C1, low-voltage capacitor C2 and anti-interference capacitor C3 arranged in an insulation core of a high-voltage electric appliance such as a high-voltage bushing, a cable terminal head or the like simultaneously. A voltage display apparatus, an insulation monitor and a local discharge detector which meet accuracy requirements access a terminal of the low-voltage capacitor C2. Energy is extracted from the terminal to power the electric appliance. A grounding part for current flow is sleeved with a current transformer. The insulation core is sleeved with annular zinc oxide arrester valve plates. Head ends of the valve plates are connected with a terminal of the bushing or the cable head. Tail ends of the valve plates are connected with a flange of the bushing or the cable head.

Claims

1. A combined electric appliance with a multi-capacitive screen insulation core, comprising an insulation core, an arrester, and an iron core coil or a hollow coil, wherein three groups of capacitive screens that are wrapped or laid with an insulation layer alternately include a main capacitor C1, a low-voltage capacitor C2 and an anti-interference capacitor C3 to constitute the insulation core, the insulation core is tightly sleeved with a plurality of annular zinc oxide valve plates, an insulation outer sheath is provided at the outmost layer, a voltage measuring apparatus, an insulation monitor and a local discharge detector access an outgoing line of the low-voltage capacitor C2, an action recorder accesses a grounding end of the arrester, and a current measuring apparatus accesses through the iron core coil or the hollow coil; with respect to an insulation body for a bushing, the main capacitor C1 thereof is composed of a group of coaxial cylindrical metal or semiconductor capacitive screens each of which the diameter is gradually increased and the length is gradually reduced, the low-voltage capacitor C2 is a group of capacitive screens that have great capacitances and are continuously wound or laid outside the last screen of the main capacitor C1, the anti-interference capacitor C2 is a string of capacitive screens that are insulated to each other and superposed to each other from a conductive screen to a grounding screen and are wound or laid from an electric terminal to the grounding screen end, while the main capacitor C1 and the low-voltage capacitor C2 are manufactured, and the main capacitor C1, the low-voltage capacitor C2 and the anti-interference capacitor C3 are embedded in the insulation core and are wound or laid in sequence; with respect to an insulation core for a cable terminal head, the main capacitor C1 thereof is a group of n cylindrical capacitive screens that are connected in series and are insulated to each other in an axial direction and superposed to each other from a conductive end to a grounding end along an insulation surface of a cable body, the low-voltage capacitor C2 is a capacitive screen that has a great capacitance and is continuously wound or laid outside the last screen of the main capacitor C1, the anti-interference capacitor C3 is a string of capacitive screens that are insulated to each other and superposed to each other from a conductive screen to a grounding screen and are wound or laid from an electric terminal to the grounding screen end, while the main capacitor C1 and the low-voltage capacitor C2 are manufactured, and the main capacitor C1, the low-voltage capacitor C2 and the anti-interference capacitor C3 are embedded in the insulation core and are wound or laid in sequence.

2. The combined electric appliance with a multi-capacitive screen insulation core according to claim 1, wherein the insulation core is not provided with the anti-interference capacitor C3.

3. The combined electric appliance with a multi-capacitive screen insulation core according to claim 1, wherein a plurality of annular zinc oxide valve plates are not provided outside the insulation core.

4. A combined electric appliance with a multi-capacitive screen insulation core, comprising an insulation core and an iron core coil or a hollow coil, wherein the insulation core comprises a main capacitor C1 and a low-voltage capacitor C2 which are composed of two groups of capacitive screens that are alternately wrapped or laid with an insulation layer, the low-voltage capacitor C2 and the main capacitor C2 constitute a capacitive voltage divider, and an insulation outer sheath is provided outside the insulation core; and a voltage measuring apparatus and/or an insulation monitor and/or a local discharge detector may selectively access an outgoing line of the low-voltage capacitor C2, and a current measuring apparatus may access through the iron core coil or the hollow coil.

5. The combined electric appliance with a multi-capacitive screen insulation core according to claim 4, wherein energy can be extracted from the outgoing line of the low-voltage capacitor C2 as a power supply for the combined electric appliance.

6. The combined electric appliance with a multi-capacitive screen insulation core according to claim 4, wherein the insulation core further comprises an anti-interference capacitor C3 which is composed of a string of capacitive screens that access in series from the electric terminal to the grounding screen.

7. The combined electric appliance with a multi-capacitive screen insulation core according to claim 4, further comprising an arrester, wherein the arrester comprises a plurality of annular zinc oxide valve plates which are provided between the outside of the insulation core and the insulation outer sheath.

8. The combined electric appliance with a multi-capacitive screen insulation core according to claim 7, wherein the insulation body is sleeved and tightly pressed with the annular zinc oxide valve plates in sequence from a conductor to a grounding body, the head ends of the valve plates are connected with the conductor, and the tail ends of the valve plates are connected with the grounding body through an automatic discharge recorder; a grounding part through which the conductor passes is sleeved with the iron core coil or the hollow coil to directly display a current amplitude, waveform and error.

9. The combined electric appliance with a multi-capacitive screen insulation core according to claim 6, wherein the main capacitor C1 is composed of a group of coaxial cylindrical metal or semiconductor capacitive screens each of which the diameter is gradually increased and the length is gradually reduced, the low-voltage capacitor C2 is a group of capacitive screens that have great capacitances and are continuously wound or laid outside the last screen of the main capacitor C1, the anti-interference capacitor C2 is a string of capacitive screens that are insulated to each other and superposed to each other from a conductive screen to a grounding screen and are wound or laid from an electric terminal to the grounding screen end, while the main capacitor C1 and the low-voltage capacitor C2 are manufactured, and the main capacitor C1, the low-voltage capacitor C2 and the anti-interference capacitor C3 are embedded in the insulation core and are wound or laid in sequence.

10. The combined electric appliance with a multi-capacitive screen insulation core according to claim 6, wherein the main capacitor C1 thereof is a group of n cylindrical capacitive screens that are connected in series and are insulated to each other in an axial direction and superposed to each other from a conductive end to a grounding end along an insulation surface of a cable body, the low-voltage capacitor C2 is a capacitive screen that has a great capacitance and is continuously wound or laid outside the last screen of the main capacitor C1, the anti-interference capacitor C3 is a string of capacitive screens that are insulated to each other and superposed to each other from a conductive screen to a grounding screen and are wound or laid from an electric terminal to the grounding screen end, while the main capacitor C1 and the low-voltage capacitor C2 are manufactured, and the main capacitor C1, the low-voltage capacitor C2 and the anti-interference capacitor C3 are embedded in the insulation core and are wound or laid in sequence.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a structural schematic drawing of the combined electric appliance with a multi-capacitive screen insulation core based on the bushing.

[0024] FIG. 2 is a structural schematic drawing of the combined electric appliance with a multi-capacitive screen insulation core based on the cable terminal head.

[0025] FIG. 3 is an equivalent circuit diagram of the cable terminal head.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0026] A structure and a manufacturing method of a combined electric appliance with a multi-capacitive screen insulation core will be described briefly with a bushing as an example: a multi-layer coaxial capacitive screen type insulation core (for example, an insulation core of a currently general capacitive type bushing) in which insulation layers (for example, epoxy glass silk, polytetrafluoroethylene, polyethylene, oiled paper or the like) are wound and laid with capacitive screens (for example, aluminum foil, semiconductor materials or the like) alternately serves as main insulation C1, wherein capacitive screens thereof are a group of coaxial cylindrical metal or semiconductor capacitive screens each of which the diameter is gradually increased and the length is gradually reduced (the size of each screen is calculated by using a principle that capacitances among the screens are equal); a group of low-voltage capacitors C2 that have great capacitances are continuously wound or laid outside the last screen of C1 to extract a signal (for example, a main insulation material is still adopted, the capacitance of C2 is selected according to the requirement to the voltage division ratio, and the size and a connecting mode of polar plates of C2 are then calculated), which constitute a capacitive voltage divider with C1; a string of capacitive screens C3 (the insulation body and the capacitive screens thereof may be made of a material same as that of C1, and are set according to a size stipulated in design) that are insulated to each other and superposed to each other from a conductor to a grounding screen are wound or laid from an electric terminal to the grounding screen end, while the main capacitor C1 and the low-voltage capacitor C2 are manufactured.

[0027] One side of the insulation body of the bushing is sleeved and tightly pressed with annular zinc oxide valve plates in sequence from a conductor to a grounding body, wherein the head ends of the valve plates are connected with the conductor, and the tail ends of the valve plates are connected with the grounding body through an automatic discharge recorder (which is placed on a place where the automatic discharge recorder is easily seen and easily replaced); a grounding part (for example, a part where the flange is arranged) through which the conductor passes is sleeved with the iron core coil or the hollow coil (the iron core coil may be used for an electromagnetic current transformer, and the hollow coil may be used for an electronic current transformer) to directly display a current amplitude, waveform and error. The zinc oxide valve plates are tightly wrapped with an outer sheath made of silicone rubber. Meanwhile, a voltage display apparatus (including amplitude, waveform and error), an insulation monitor and a local discharge detector may access a terminal led out of C2. Energy can be extracted from the terminal as a power supply for the combined electric appliance

[0028] A structure and a manufacturing method of a combined electric appliance with a multi-capacitive screen insulation core will be described briefly with a cable terminal head as an example: main capacitive screens C1 for the cable terminal head are a group of n cylindrical capacitive screens (for example, made of aluminum foil or semiconductor materials) that are arranged inside an insulation body (for example, epoxy glass silk, polytetrafluoroethylene, polyethylene or the like) intermittently in an axial direction from a conductive end to a grounding end along an insulation surface (for example, crosslinked polyethylene) of a cable body. Because this string of capacitive screens shift continuously from the conductor to the grounding part according to positions suggested in design, a low-voltage capacitor that has great capacitances and is continuously wound or laid outside the last screen of the main capacitor C1 is referred to as a low-voltage capacitor C2 for short (for example, a main insulation material is still adopted, the capacitance of C2 is selected according to the requirement to the voltage division ratio, and the size and a connecting mode of polar plates of C2 are then calculated), which constitutes a capacitive voltage divider with C1. In order to prevent the interference of other electric appliances or electric conductors in a substation to C1, a string of anti-interference capacitive screens C3 (the insulation body and the capacitive screens thereof may be made of a material same as that of C1, and are set according to a size stipulated in design) that are insulated to each other and superposed to each other from a conductor to a grounding screen and are wound or laid from an electric terminal to the grounding screen end, while C1 and C2 are manufactured.

[0029] The insulation core for the cable terminal head is sleeved and tightly pressed with annular zinc oxide valve plates in sequence from a conductor (a wiring terminal) to a grounding body, wherein the head ends of the valve plates are connected with the conductor, and the tail ends of the valve plates are connected with the grounding body through an automatic discharge recorder (which is placed on a place where the automatic discharge recorder is easily seen and easily replaced); a grounding part (for example, the root of the cable terminal head) through which the conductor passes is sleeved with the iron core coil or the hollow coil (the iron core coil may be used for an electromagnetic current transformer, and the hollow coil may be used for an electronic current transformer) to directly display a current amplitude, waveform and error. The zinc oxide valve plates are tightly wrapped with an outer sheath 5 made of silicone rubber. Meanwhile, a voltage display apparatus (including amplitude, waveform and error), an insulation monitor and a local discharge detector access a terminal led out of C2. Energy can be extracted from the terminal as a power supply for the combined electric appliance.