1000kV nuclear power transformer outgoing line structure and nuclear power transformer

Abstract

The invention belongs to the field of nuclear power transformers, and provides a 1000kV nuclear power transformer wire outlet structure and a nuclear power transformer. The wire outlet structure of the 1000kV nuclear power transformer comprises a lead wire voltage-sharing tube, and an insulating layer is arranged on the outer side of the lead wire voltage-sharing tube; a copper braided wire is arranged in the lead voltage-sharing pipe, one end of the copper braided wire is connected with the high-pressure oil-SF6 sleeve through a sleeve wiring board, and the other end of the copper braided wire is connected with a high-voltage winding outgoing line; a high-frequency wave suppression assembly is arranged between the copper braided wire and the sleeve wiring board and comprises a plurality of sections of copper damping leads which are connected in series; each section of copper damping lead is a spiral copper pipe; and a copper shielding wire is embedded in the spiral part of each spiral copper pipe.

Description

Technical Field

[0001] The invention belongs to the field of nuclear power transformers, and in particular relates to a 1000kV nuclear power transformer outlet structure and a nuclear power transformer. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] At present, nuclear power plants generally adopt a 500kV line transmission scheme, and the high-voltage end of the transformer has always adopted the oil-SF6 bushing and the GIS switch direct connection line mode. With the maturity of ultra-high voltage power transmission technology, nuclear power plants will adopt a 1000kV transmission scheme, and the 1000kV transformer will adopt the oil-SF6 bushing and the GIS switch direct connection line mode. Since the GIS switch will bring the problem of very fast transient overvoltage (VFTO) when it is operated, it is necessary to develop new technologies to enable the 1000kV transformer to withstand the VFTO caused by the GIS switch action and improve the reliability of nuclear power transformers.

[0004] For transformers directly connected to GIS, VFTO will be transmitted to the transformer through the GIS busbar and connecting wires after it is generated. The rise time of the VFTO steep wave head is only tens of nanoseconds, which is much shorter than the wave head rise time of the lightning impulse chopped wave test. The frequency of up to several megahertz caused by the propagation through the SF6-oil casing is easy to propagate between turns and layers of the transformer winding, and excite extremely high resonant overvoltage inside the transformer winding, which is very harmful to the injection and longitudinal insulation of the transformer. When the steepness and amplitude of the waveform cannot be effectively suppressed from its source, the incoming line on the high-voltage side of the transformer and even the head end of the high-voltage winding will be the last barrier for VFTO to invade the transformer. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a 1000kV nuclear power transformer outlet structure and a nuclear power transformer, which can suppress the steepness and amplitude of VFTO, thereby improving the ability of the 1000kV transformer to withstand VFTO.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides a 1000kV nuclear power transformer outgoing line structure.

[0008] A 1000kV nuclear power transformer outlet structure, comprising: a lead voltage equalizing tube, an insulating layer is arranged on the outside of the lead voltage equalizing tube; a copper braided wire is arranged inside the lead voltage equalizing tube, one end of the copper braided wire is connected to a high-voltage oil-SF6 bushing through a bushing terminal block, and the other end is connected to a high-voltage winding lead wire;

[0009] A high-frequency wave suppression component is arranged between the copper braided wire and the sleeve terminal block, and the high-frequency wave suppression component includes a plurality of sections of copper damping lead wires connected in series; each section of the copper damping lead wire is a spiral copper tube; and a copper shielding wire is embedded inside the tube between the spirals of each spiral copper tube.

[0010] As an implementation mode, each section of the copper damping lead has a built-in nonlinear resistance rod, and the nonlinear resistance rod is assembled from multiple sections of zinc oxide valve plates connected in series.

[0011] As an implementation manner, the end of the copper braided wire is also connected to the high-voltage winding lead wire.

[0012] As an implementation mode, an insulating support is further provided between the end of the copper braided wire and the high voltage winding lead wire.

[0013] As an implementation method, the performance parameters of the spiral copper tube are determined based on the VFTO overvoltage and high-frequency leakage current.

[0014] As an implementation method, the formula for determining the performance parameters of the spiral copper tube is: U=IX; X=ωL; ω=2πf; wherein U, I, X, ω, L, and f represent VFTO overvoltage, high-frequency leakage current, reactance of the spiral copper tube, angular velocity of the spiral copper tube, inductance of the spiral copper tube, and frequency of the spiral copper tube, respectively.

[0015] As an implementation method, the inductance L is proportional to the square of the number of spirals of the spiral copper tube.

[0016] As an implementation method, when the VFTO amplitude decreases by 0.2-0.3 pu, if the inner diameter of the lead voltage equalizing tube is 130 mm, the inner and outer diameters of the spiral copper tube are determined to be 80 mm and 100 mm respectively, and the length of a single-section spiral copper tube is 60 mm.

[0017] As an implementation method, the pitch is calculated to be 12 mm based on the required number of turns of inductance and the current carrying capacity.

[0018] A second aspect of the present invention provides a nuclear power transformer.

[0019] A nuclear power transformer comprises the 1000kV nuclear power transformer outgoing line structure as described above.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides a 1000kV nuclear power transformer outlet structure, which improves the ability of the ultra-high voltage transformer to withstand VFTO; when the disconnector contacts in the GIS are actuated, the voltage suddenly rises or drops to generate a steep traveling wave, which is reflected and superimposed multiple times at the nodes where the wave impedance changes, forming a few nanoseconds of wavefront time, tens to hundreds of megahertz, and an ultra-fast transient overvoltage with an amplitude of 2 to 3 times the rated voltage; after VFTO is generated, it will be transmitted to the transformer through the GIS busbar and connecting wires, endangering the safe and stable operation of the transformer. The present invention has developed a new high-voltage outlet structure for 1000kV transformers, which effectively suppresses the steepness and amplitude of the VFTO that invades the high-voltage winding of the transformer, thereby improving the insulation margin of the transformer winding and the reliability of the nuclear power transformer.

[0022] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 It is an assembly diagram of the high-voltage outlet structure of a 1000kV nuclear power transformer structure according to an embodiment of the present invention;

[0025] FIG. 2( a ) is an assembly diagram of a VFTO suppression device for a 1000 kV nuclear power transformer outgoing line structure according to an embodiment of the present invention;

[0026] FIG2( b ) is a front view of a VFTO suppression device of a 1000 kV nuclear power transformer outgoing line structure according to an embodiment of the present invention;

[0027] Figure 3 A damping lead wire of a 1000kV nuclear power transformer outgoing line structure according to an embodiment of the present invention;

[0028] Figure 4 The present invention is a cross-sectional view of a spiral copper tube wall of a damping lead wire of a 1000kV nuclear power transformer outgoing line structure according to an embodiment of the present invention.

[0029] Among them: 1. High-frequency wave suppression component; 2. Copper damping lead; 3. Zinc oxide valve plate; 4. Zinc oxide valve plate insulation; 5. Plum blossom contact connector; 6. Insulation support; 7. Body connection joint; 8. Damping busbar insulation; 9. Bushing terminal block; 10. Copper braided wire; 11. Lead equalizing tube; 12. Equalizing tube insulation; 13. High-voltage oil-SF6 bushing; 14. High-voltage winding lead wire. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention and should not be understood as limitations on the present invention.

[0034] In the present invention, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. Relevant scientific research or technical personnel in this field can determine the specific meanings of the above terms in the present invention according to specific circumstances, and they should not be understood as limiting the present invention.

[0035] according to Figure 1 As shown, this embodiment provides a 1000kV nuclear power transformer outlet structure and a nuclear power transformer, including: a lead equalizing tube, an insulating layer is arranged on the outside of the lead equalizing tube 11; a copper braided wire 10 is arranged inside the lead equalizing tube 11, one end of the copper braided wire 10 is connected to the high-voltage oil-SF6 bushing 13 through the bushing terminal board 9, and the other end is connected to the high-voltage winding lead 14;

[0036] A high-frequency wave suppression component 1 is arranged between the copper braided wire 10 and the sleeve terminal block 9, and the high-frequency wave suppression component 1 includes a plurality of sections of copper damping leads 2 connected in series; each section of the copper damping lead 2 is a spiral copper tube; a copper shielding wire is embedded inside the spiral of each spiral copper tube, such as Figure 3 and Figure 4 shown.

[0037] In this embodiment, each section of the copper damping lead has a built-in nonlinear resistance rod, and the nonlinear resistance rod is assembled from multiple sections of zinc oxide valve plates connected in series.

[0038] As shown in Figures 2(a) and 2(b), in this embodiment, the copper braided wire 10 between the cold-pressed joint 7 and the bushing terminal block 9 is disconnected, and the two ends of the high-frequency wave suppression component 1 are connected at the break. Specifically, the high-frequency wave suppression component 1 is composed of a copper damping lead 2, a zinc oxide valve plate 3, a zinc oxide valve plate insulation 4, a plum blossom contact connector 5, a damping busbar insulation 8, etc., wherein a plurality of zinc oxide valve plates 3 are connected together to form a group of zinc oxide valve plate units, and each group of zinc oxide valve plate units is connected in parallel with each section of the damping busbar inner wall 2 using a plum blossom contact 5 connector to be assembled into an integrated component, and the outer surface of the damping busbar is covered with the damping busbar insulation 8 to ensure electrical insulation from the inner wall of the lead equalizing tube 11.

[0039] In this embodiment, an insulating support 6 is provided between the end of the copper braided wire and the high voltage winding lead wire. The high frequency wave suppression component 1 is assembled into one and then fixed to the inner wall of the lead wire equalizing tube 11 by the insulating support 6 .

[0040] In this embodiment, the end of the copper braided wire is also connected to the high-voltage winding lead wire 14. Specifically, the end of the copper braided wire is connected to the high-voltage winding lead wire 14 through the device body connection joint 7.

[0041] The spiral copper tube plays a current-carrying role under working conditions. This VFTO outlet suppression structure can be equivalent to a model in which an inductor and a nonlinear resistor are connected in parallel on the lead according to the circuit connection. There is almost no energy loss for the power frequency voltage passing through during normal operation, and it only plays a current-carrying role. However, when the high-frequency VFTO passes through, the copper solenoid inductance can suppress the amplitude and steepness of the overvoltage, and the nonlinear resistor consumes the high-frequency waveform energy. The high-voltage outlet VFTO suppression device has a high-strength glass fiber insulation support and can be easily installed in the equalizing tube of the high-voltage outlet. The VFTO suppression device is installed in the equalizing tube, which can shield the electrodes of the damping lead and the connector, and improve the electric field strength of the high-voltage outlet device.

[0042] The product of the inner and outer diameters of the spiral copper tube and the pitch determines the flow rate of the wire. Since the larger the capacity of the product, the larger the pitch. The copper damping busbar is processed into multiple sections. When the high-frequency voltage passes through, a potential difference is formed at both ends of each spiral copper tube, which can quickly flow through the nonlinear resistor in parallel to release energy. Due to the nonlinear resistance characteristics of the zinc oxide valve plate, when the VFTO amplitude is higher, the voltage difference of each spiral copper tube is larger, and the energy is released faster. The length of the spiral copper tube is designed so that the voltage difference does not cause discharge to the gap of the voltage equalizing tube. Copper shielding wires are embedded between the spirals of the spiral copper tube to increase the series capacitance between the spirals, thereby increasing the ratio of the series capacitance to the capacitance of the spiral copper tube to the ground. It can also improve the impact distribution after the VFTO enters the lead and reduce the steepness and peak value of its waveform. When the voltage at both ends of the zinc oxide valve plate is greater than its clamping voltage, the zinc oxide valve plate is turned on and energy is released.

[0043] The performance parameters of the spiral copper tube are determined based on the VFTO overvoltage and high-frequency leakage current.

[0044] The formula for determining the performance parameters of the spiral copper tube is: U = IX; X = ωL; ω = 2πf; where U, I, X, ω, L, and f represent the VFTO overvoltage, high-frequency leakage current, reactance of the spiral copper tube, angular velocity of the spiral copper tube, inductance of the spiral copper tube, and frequency of the spiral copper tube, respectively. The inductance L is proportional to the square of the number of spirals of the spiral copper tube.

[0045] When the VFTO amplitude needs to be reduced by 0.2-0.3pu (about 200kV-300kV), the inner and outer diameters of the copper spiral copper tube are determined to be 80mm and 100mm respectively according to the inner diameter of the equalizing tube of 130mm and the diameter of the zinc oxide valve plate. The length of a single-section spiral copper tube is about 60mm, and the pitch is calculated to be 12mm according to the required number of turns of inductance and the current carrying capacity.

[0046] In one or more embodiments, a nuclear power transformer comprises the 1000 kV nuclear power transformer outgoing line structure as described above.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A 1000kV nuclear power transformer outgoing line structure, characterized in that: include: A lead voltage equalizing tube, wherein an insulating layer is arranged on the outside of the lead voltage equalizing tube; a copper braided wire is arranged inside the lead voltage equalizing tube, wherein one end of the copper braided wire is connected to the high-voltage oil-SF6 bushing through the bushing terminal block, and the other end is connected to the high-voltage winding lead wire; A high-frequency wave suppression component is arranged between the copper braided wire and the sleeve terminal block, and the high-frequency wave suppression component includes a plurality of sections of copper damping lead wires connected in series; each section of the copper damping lead wire is a spiral copper tube; and a copper shielding wire is embedded inside the tube between the spirals of each spiral copper tube.

2. The 1000kV nuclear power transformer outlet structure according to claim 1, characterized in that: Each section of the copper damping lead wire is internally provided with a nonlinear resistance rod, and the nonlinear resistance rod is assembled from a plurality of sections of zinc oxide valve sheets connected in series.

3. The 1000kV nuclear power transformer outlet structure according to claim 1, characterized in that: The end of the copper braided wire is also connected to the high voltage winding lead wire.

4. The 1000kV nuclear power transformer outgoing line structure as claimed in claim 3, characterized in that: An insulating support is also provided between the end of the copper braided wire and the high voltage winding lead wire.

5. The 1000kV nuclear power transformer outgoing line structure according to claim 1, characterized in that: The performance parameters of the spiral copper tube are determined based on the VFTO overvoltage and high-frequency leakage current.

6. The 1000kV nuclear power transformer outgoing line structure as claimed in claim 5, characterized in that: The formula for determining the performance parameters of the spiral copper tube is: U=IX; X=ωL; ω=2πf; wherein U, I, X, ω, L, and f represent VFTO overvoltage, high-frequency leakage current, reactance of the spiral copper tube, angular velocity of the spiral copper tube, inductance of the spiral copper tube, and frequency of the spiral copper tube, respectively.

7. The 1000kV nuclear power transformer outgoing line structure according to claim 5, characterized in that: The inductance L is proportional to the square of the number of spirals of the spiral copper tube.

8. The 1000kV nuclear power transformer outgoing line structure according to claim 1, characterized in that: When the VFTO amplitude decreases by 0.2-0.3pu, if the inner diameter of the lead voltage-equalizing tube is 130mm, the inner and outer diameters of the spiral copper tube are determined to be 80mm and 100mm respectively, and the length of a single-section spiral copper tube is 60mm.

9. The 1000kV nuclear power transformer outgoing line structure according to claim 8, characterized in that: The pitch is calculated to be 12mm based on the required number of turns of inductance and the current carrying capacity.

10. A nuclear power transformer, characterized in that: It comprises a 1000kV nuclear power transformer outgoing line structure as claimed in any one of claims 1 to 9.

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