Starting resistor and switch device

Abstract

The invention relates to a starting resistor and switch equipment, the starting resistor comprises a grounding sealing box, an inner cavity of the grounding sealing box is an insulating gas filling cavity used for filling insulating gas, a resistor is installed in the grounding sealing box, and the grounding sealing box is provided with a series connection interface used for connecting the resistor to a switch equipment line in series; the resistor is arranged in the grounding sealing box, the electric arc in the inner cavity of the grounding sealing box is blocked through the insulating gas, and the starting resistor is mounted on the ground on the premise of ensuring safety; the overall occupied area of the equipment is reduced, meanwhile, the gravity center of the product is lowered, and the anti-seismic performance of the equipment is better.

Description

Technical Field

[0001] The invention relates to the field of resistors with insulating gas filled between a shell and a resistor element, and in particular to a starting resistor and a switch device. Background Art

[0002] In recent years, the flexible DC transmission technology of modular multilevel converter (MMC) has become the mainstream of DC transmission projects. When starting, the flexible DC transmission system needs to precharge the converter capacitor, and the electrical circuit will generate impact current and impact voltage during startup, so it is necessary to connect a starting resistor next to the starting circuit as a slow starting measure for the flexible DC transmission system. The slow starting measures in the prior art generally use open box starting resistors as slow starting resistors, such as a high-voltage flexible DC transmission starting resistor disclosed in the Chinese invention patent with publication number CN109300635A, which is a multi-layered resistor box with at least 2 resistor units per layer as the starting resistor of the flexible DC transmission system. The resistor boxes are connected by bushings, and the bushings are provided with electrical connections for series resistor strings; the adjacent two layers of resistor boxes are connected and supported by insulating support columns. Through modular design, while increasing the resistance value and improving the impact resistance of the starting resistor, the multi-layer resistor boxes are arranged in the height direction, which reduces the footprint of the equipment.

[0003] However, the problem with this technical solution is that if the starting current and starting voltage in a certain flexible DC transmission system are large, in order to increase the resistance of the starting resistor, more resistor boxes need to be stacked in series, and the starting resistor needs to withstand extremely high voltage and current. It is very dangerous to place it close to the ground. In this way, the overall height of the starting resistor will increase, and the center of gravity will increase accordingly, causing the structural stability of the starting resistor to decrease, making it easy to collapse and damage the starting resistor itself and nearby electrical equipment. Summary of the invention

[0004] The purpose of the present invention is to provide a starting resistor to solve the problems of high center of gravity, low structural stability and easy collapse of the starting resistor in the prior art; the purpose of the present invention is also to provide a switching device to solve the above technical problems.

[0005] To achieve the above-mentioned purpose, the present invention provides a starting resistor, including a grounding sealing box, the inner cavity of the grounding sealing box is an insulating gas filling cavity for filling insulating gas, a resistor is installed in the grounding sealing box, and a series interface for connecting the resistor in series to the switching device line is provided on the grounding sealing box.

[0006] Furthermore, the grounding sealing box includes a circular box body and upper and lower covers, the lower cover is provided with an insulating base for supporting the resistor, one serial connection interface is provided on the upper cover, and the other is provided near the bottom of the box body.

[0007] Furthermore, the resistor includes a plurality of vertically extending resistor strings, the plurality of resistor strings are evenly arranged around a circle, and two adjacent resistor strings are connected in series at the top or bottom, the insulating base is a circular base, and the plurality of resistor strings are fixed above the circular base.

[0008] Furthermore, the insulating base includes a circular cylinder, a conductive plate is fixed to the upper end of the circular cylinder, at least part of the conductive plate is an arc plate, and two resistor strings are installed on each arc plate to realize the series connection of the two resistor strings at the bottom.

[0009] Furthermore, the resistor string includes an insulating rod and a resistor sheet stacked on the insulating rod, and the resistor string also includes a conductive support seat for supporting the resistor sheet mounted on the insulating rod, and the bottom end of the insulating rod is fixed on the conductive support seat; the upper end of the insulating rod is also detachably connected with a conductive shield, and the resistor string is fixed to the conductive plate through the conductive support seat, and some adjacent resistor strings are connected in series at the top by two conductive rods with conductive shields connected at the top.

[0010] Furthermore, among all the resistor strings connected in series, an upward electrical connection interface is provided on the conductive shield of a resistor string at one end of the circuit, and a horizontal electrical connection interface is provided on the conductive support seat of a resistor string at the other end of the circuit.

[0011] Furthermore, a connecting hole is provided on the upper end ring surface of the circular cylinder of the insulating base, and the conductive plate is fixed to the upper end ring surface of the circular cylinder by bolts matching the connecting hole.

[0012] Furthermore, the conductive support seat includes a support tube, a top plate for supporting the resistor string is provided at the upper end of the support tube, a through hole for inserting an insulating rod is opened in the center of the top plate, and a locking nut is screwed on the insulating rod at the lower side of the top plate to tighten the resistor sheet mounted on the insulating rod.

[0013] Beneficial effects: The present invention provides a pioneering starting resistor, including a grounding sealing box, the inner cavity of the grounding sealing box is an insulating gas filling cavity for filling insulating gas, a resistor is installed in the grounding sealing box, and the grounding sealing box is provided with a series interface for connecting the resistor in series to the switch device line; the resistor is set in the grounding sealing box, and the insulation between the resistor and the inside of the grounding sealing box is ensured by insulating gas, so that the starting resistor can be installed on the ground under the premise of ensuring safety, reducing the overall footprint of the equipment, while lowering the center of gravity, improving the seismic resistance of the equipment, and solving the problems of high center of gravity and easy collapse of the resistor box in the prior art.

[0014] To achieve the above-mentioned purpose, the present invention also provides a switch device, including a grounding sealing box, the inner cavity of the grounding sealing box is an insulating gas filling cavity for filling insulating gas, a resistor is installed in the grounding sealing box, and the grounding sealing box is provided with a series interface for connecting the resistor in series to the switch device line.

[0015] Furthermore, the grounding sealing box includes a circular box body and upper and lower covers, the lower cover is provided with an insulating base for supporting the resistor, one serial connection interface is provided on the upper cover, and the other is provided near the bottom of the box body.

[0016] Furthermore, the resistor includes a plurality of vertically extending resistor strings, the plurality of resistor strings are evenly arranged around a circle, and two adjacent resistor strings are connected in series at the top or bottom, the insulating base is a circular base, and the plurality of resistor strings are fixed above the circular base.

[0017] Furthermore, the insulating base includes a circular cylinder, a conductive plate is fixed to the upper end of the circular cylinder, at least part of the conductive plate is an arc plate, and two resistor strings are installed on each arc plate to realize the series connection of the two resistor strings at the bottom.

[0018] Furthermore, the resistor string includes an insulating rod and a resistor sheet stacked on the insulating rod, and the resistor string also includes a conductive support seat for supporting the resistor sheet mounted on the insulating rod, and the bottom end of the insulating rod is fixed on the conductive support seat; the upper end of the insulating rod is also detachably connected with a conductive shield, and the resistor string is fixed to the conductive plate through the conductive support seat, and some adjacent resistor strings are connected in series at the top by two conductive rods with conductive shields connected at the top.

[0019] Furthermore, among all the resistor strings connected in series, an upward electrical connection interface is provided on the conductive shield of a resistor string at one end of the circuit, and a horizontal electrical connection interface is provided on the conductive support seat of a resistor string at the other end of the circuit.

[0020] Furthermore, a connecting hole is provided on the upper end ring surface of the circular cylinder of the insulating base, and the conductive plate is fixed to the upper end ring surface of the circular cylinder by bolts matching the connecting hole.

[0021] Furthermore, the conductive support seat includes a support tube, a top plate for supporting the resistor string is provided at the upper end of the support tube, a through hole for inserting an insulating rod is opened in the center of the top plate, and a locking nut is screwed on the insulating rod at the lower side of the top plate to tighten the resistor sheet mounted on the insulating rod.

[0022] Furthermore, it includes a horizontally arranged main bus, the main bus is connected to a parallel branch, a bypass switch is connected in series to the upper parallel branch, a starting resistor is connected in series to the lower parallel branch, and a current transformer is connected in series to the parallel branch.

[0023] Beneficial effects: The present invention improves the starting resistor of the starting circuit in the switch device in the prior art, comprises a grounding sealing box, the inner cavity of the grounding sealing box is an insulating gas filling cavity for filling insulating gas, a resistor is installed in the grounding sealing box, and a series interface for connecting the resistor in series to the switch device line is provided on the grounding sealing box; the resistor is arranged in the grounding sealing box, and the insulation between the resistor and the inside of the grounding sealing box is ensured by the insulating gas, so that the starting resistor can be installed on the ground under the premise of ensuring safety, thereby reducing the overall footprint of the equipment, while lowering the center of gravity, improving the seismic resistance of the equipment, and solving the problems of high center of gravity and easy collapse of the resistor box in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the overall cross-sectional view of the starting resistor; Figure 2 This is the assembly structure diagram of the starting resistor without a grounding sealing box installed; Figure 3 It is a schematic diagram of the structure of the resistor string in the starting resistor; Figure 4 It is a top view schematic diagram of the conductive plate in the starting resistor installed on the insulating base; Figure 5 This is a schematic diagram of the overall assembly of the switchgear with a starting resistor installed.

[0025] In the figure: 1. resistor string; 101. conductive shield; 102. pin shaft; 103. resistor sheet; 104. insulating rod; 105. conductive support seat; 1051. support cylinder; 1052. top plate; 1053. locking nut; 1054. annular flange; 2. electrical connection interface; 3. insulating base; 301. circular cylinder; 4. conductive rod; 5. conductive plate; 501. arc plate; 502. circular plate; 503. mounting hole; 504. base connection hole; 6. grounding sealing box; 601. upper cover plate; 602. lower cover plate; 603. box body; 604. insulating gas filling cavity; 605. series connection interface; 8. current transformer; 9. bypass switch; 901. upper interface; 902. lower interface; 10. main bus. DETAILED DESCRIPTION

[0026] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0027] The principle and concept of the present invention is to design a starting resistor, including a grounding sealing box and a resistor installed in the grounding sealing box, and to ensure insulation between the resistor and the inside of the grounding sealing box by insulating gas to ensure that the grounding sealing box is not electrified. The grounding sealing box is installed on the ground and the resistor in the grounding sealing box is connected to the switch device circuit, thereby reducing the overall height of the starting resistor.

[0028] Based on the above principles and concepts, the present invention provides multiple embodiments of the switch device for further explanation.

[0029] Based on the above principles, Figure 5 The switch device provided by the present invention includes a horizontally extended main bus 10, the main bus 10 is connected to a parallel branch, the switch device includes a bypass switch 9, the bypass switch 9 is provided with an upper interface 901 and a lower interface 902, the bypass switch 9 is connected in series to the parallel branch on the upper side of the main bus 10 through the upper and lower interfaces, the switch device also includes a starting resistor connected in series to the parallel branch on the lower side of the main bus 10, and a current transformer 8 is also connected in series to the parallel branch on the lower side of the main bus 10.

[0030] like Figure 1 , Figure 2 and Figure 5 In the embodiment provided, the starting resistor includes a grounding sealed box 6 and a resistor installed in the grounding sealed box 6. The inner cavity of the grounding sealed box 6 is an insulating gas filling cavity 604 for filling insulating gas. The grounding sealed box 6 is provided with a serial interface 605 for connecting the resistor in series to the switchgear line. The starting resistor is connected as a whole to the switchgear line; when precharging the converter, the bypass switch 9 is turned on, and the impact current and impact voltage generated during precharging in the electric circuit are consumed by the starting resistor. The starting resistor provided by the present invention sets the resistor in the grounding sealed box 6, and the inner cavity of the grounding sealed box 6 is filled with insulating gas to isolate the arc in the box. The starting resistor is installed on the ground as a whole on the premise that the grounding sealed box 6 is not charged, which reduces the height of the starting resistor and the center of gravity.

[0031] Based on the above embodiments, in one embodiment, Figure 1In the provided embodiment, the grounding sealed box 6 comprises an upper cover plate 601, a lower cover plate 602 and a circular box body 603, and the upper and lower cover plates are fixed to the box body 603 by threaded fasteners. An insulating base 3 for supporting the resistor is provided on the lower cover plate 602; there are two serial connection interfaces 605 for serially connecting the resistor to the switch device line, one is provided on the upper cover plate 601, and the other is provided on the box body 603 near the bottom; in another embodiment, the box body 603 of the grounding sealed box 6 can be changed according to actual use, such as using a square box body 603 to accommodate resistors arranged in a matrix, and different shapes of the box body 603 all fall within the protection scope of the present invention.

[0032] Based on the above embodiments, in one embodiment, Figure 1 , Figure 2 In the provided embodiment, the insulating base 3 is a circular base, and the resistor includes 5 vertically arranged resistor strings 1, which are evenly arranged on the insulating base 3 in a circular shape of 72°, and two adjacent resistor strings 1 are connected in series through an electrical connection device arranged at the top or bottom of the resistor string 1, and the electrical connection device can be an electrical connection unit such as a conductive rod or a wire. In another embodiment, the arrangement of the resistor strings will also change according to the different shapes of the insulating bases, and the resistor strings 1 can also be arranged in a matrix and connected in series on the square insulating base 3.

[0033] Based on the above embodiments, in one embodiment, Figure 1 , Figure 2 and Figure 4 In the provided embodiment, the insulating base 3 includes a circular cylinder 301, and a conductive plate 5 is provided on the upper end surface of the circular cylinder 301. The conductive plate 5 includes two arc plates 501 and a circular plate 502. Two resistor strings 1 can be installed on each arc plate 501 and the two resistor strings 1 are connected in series at the bottom of the two resistor strings 1. In another embodiment, an interface is provided at the bottom of the resistor string 1, and the two groups of resistor strings 1 are connected in series at the bottom by a conductive rod inserted into the interface at the bottom of the two groups of resistor strings 1.

[0034] Based on the above embodiments, in one embodiment, Figure 3In the provided embodiment, the resistor string 1 includes an insulating rod 104, on which a plurality of resistor sheets 103 are stacked and sleeved, and the resistor string 1 also includes a conductive support seat 105 for supporting the resistor string 1, and the resistor string 1 is arranged in a vertical direction by inserting the insulating rod 104 into the conductive support seat 105; the conductive shield 101 is hemispherical, and a plug hole corresponding to the cross section of the insulating rod 104 is provided at the center of the bottom plane of the conductive shield 101 perpendicularly to the plane upward, and a through plug hole is provided near the upper end of the plug hole in a direction perpendicular to the vertical axis of the plug hole, and continues to extend a certain length along this direction, The pin hole of the conductive shield 101 is not completely penetrated, and a through hole corresponding to the diameter of the pin hole is further provided near the top of the insulating rod 104. The top of the insulating rod 104 is inserted into the above-mentioned plug-in hole, the through hole at the top of the insulating rod 104 is rotated to be coaxial with the pin hole, and the pin 102 is inserted into the pin hole to fix the conductive shield 101 on the insulating rod 104; the resistor string 1 is fixed to the conductive plate 5 through a conductive support seat 105, and the resistor strings 1 on the two conductive plates 5 are installed on the top of the resistor string 1, and the conductive rods 4 of the conductive shields 101 on the top of the two resistor strings 1 are connected to realize the series connection of the resistor strings 1 on the top of different conductive plates 5.

[0035] Based on the above embodiments, in one embodiment, Figure 1-5 In the provided embodiment, among all the resistor strings 1 connected in series, an upward electrical connection interface 2 is provided on the conductive shield 101 of a resistor string 1 at one end, so as to connect the starting resistor to the switching device circuit; a horizontal electrical connection interface 2 is provided on the conductive support seat 105 of a resistor string 1 at the other end, and the two electrical connection interfaces 2 correspond to the positions of the two series connection interfaces 605 provided on the grounding sealing box 6; the electrical connection interface 2 is connected to the conductive element such as a conductive rod or a wire, and the conductive element is connected to the switching device circuit through the series connection interface 605; in another embodiment, according to the actual layout of different switching device circuits, the position of the series connection interface 605 on the grounding sealing box 6 will also change accordingly. When the two series interfaces 605 of the grounding sealing box 6 are both provided on the upper cover plate 601, the electrical connection interfaces 2 of the resistor strings 1 at both ends need to be provided on the conductive shield 101 at the top of the two resistor strings 1.

[0036] Based on the above embodiments, in one embodiment, Figure 1-2In the provided embodiment, a connection hole is provided on the upper annular surface of the circular cylinder 301 of the insulating base 3, and a mounting hole 503 is provided on the conductive plate 5. The conductive plate 5 is fixed to the upper annular surface of the circular cylinder 301 by corresponding mounting holes 503 and the connecting holes, and bolts for matching the connecting holes are installed in the holes. In another embodiment, in order to facilitate the installation of the conductive plate 5, an annular flange plate is installed on the upper annular surface of the circular cylinder 301, and the conductive plate 5 is fixed to the annular flange plate through flange holes and bolts and nuts.

[0037] Based on the above embodiments, in one embodiment, Figure 3 In the embodiment provided, the conductive support seat 105 also includes a support cylinder 1051, a top plate 1052 for supporting the resistor string is installed on the upper end of the support cylinder 1051, a through hole for inserting the insulating rod 104 is opened in the center of the top plate 1052, a locking nut 1053 corresponding to the through hole is arranged at the bottom of the top plate 1052, and a thread of a certain length is arranged at the bottom of the insulating rod 104. Tighten upwards to compress the resistor 103 mounted on the insulating rod 104 between the top plate 1052 and the conductive shield 101; an annular flange 1054 is also installed at the bottom of the support tube 1051 to fix the conductive support seat 105 on the conductive plate 5; the mounting holes set on the annular flange 1054 correspond to the base connection holes 504 on the conductive plate 5, and the conductive support seat 105 is fixed to the conductive plate 5 by bolts; in another embodiment, the conductive support seat 105 can also be replaced by a large-area conductive plate, and the insulating rod 104 is inserted into the large-area conductive plate, which supports the insulating rod 104 and the resistor 103 mounted on the insulating rod 104, while connecting multiple resistor strings 1 in series.

[0038] The starting resistor provided by the present invention is the starting resistor used in the switch device of the above-mentioned embodiment, and the embodiment of the starting resistor will not be described in detail herein.

[0039] When the starting resistor of the present invention is in use, the gas filling chamber 604 of the grounding sealing box 6 is filled with insulating gas, and the starting resistor is connected to the switch device line. Since the grounding sealing box 6 is completely grounded and the insulating gas serves to isolate the arc in the grounding sealing box 6, the starting resistor is placed on the ground under the premise of strictly ensuring that the box body of the starting resistor is not energized, thereby avoiding the use of stacked starting resistors with a higher center of gravity in the prior art and reducing the overall volume of the switch device.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A starting resistor, characterized in that: It comprises a grounding sealing box, the inner cavity of which is an insulating gas filling cavity for filling insulating gas, a resistor is installed in the grounding sealing box, and a series connection interface for connecting the resistor in series to the switch equipment line is provided on the grounding sealing box.

2. A starting resistor according to claim 1, characterized in that: The grounding sealed box includes a circular box body and upper and lower covers. The lower cover is provided with an insulating base for supporting the resistor. One serial connection interface is provided on the upper cover, and the other is provided near the bottom of the box body.

3. A starting resistor according to claim 2, characterized in that: The resistor comprises a plurality of vertically extending resistor strings, the plurality of resistor strings are evenly arranged around a circle, and two adjacent resistor strings are connected in series at the top or bottom. The insulating base is a circular base, and the plurality of resistor strings are fixed above the circular base.

4. A starting resistor according to claim 3, characterized in that: The insulating base comprises a circular cylinder, a conductive plate is fixed on the upper end of the circular cylinder, at least part of the conductive plate is an arc plate, and two resistor strings are installed on each arc plate to realize the series connection of the two resistor strings at the bottom.

5. A starting resistor according to claim 4, characterized in that: The resistor string includes an insulating rod and a resistor sheet stacked on the insulating rod. The resistor string also includes a conductive support seat for supporting the resistor sheet mounted on the insulating rod. The bottom end of the insulating rod is fixed on the conductive support seat. The upper end of the insulating rod is also detachably connected with a conductive shield. The resistor string is fixed to the conductive plate through the conductive support seat. Some adjacent resistor strings are connected in series at the top through two conductive rods with conductive shields connected at the top.

6. A starting resistor according to claim 5, characterized in that, Among all the resistor strings together, an upward electrical connection interface is provided on the conductive shield of a resistor string at one end of the circuit, and a horizontal electrical connection interface is provided on the conductive support seat of a resistor string at the other end of the circuit.

7. A starting resistor according to claim 4, characterized in that: A connecting hole is arranged on the upper end ring surface of the circular cylinder of the insulating base, and the conductive plate is fixed on the upper end ring surface of the circular cylinder by bolts matched with the connecting hole.

8. A starting resistor according to claim 5 or 6, characterized in that: The conductive support seat includes a support tube, the upper end of which is provided with a top plate for supporting the resistor string, a through hole for inserting an insulating rod is opened in the center of the top plate, and a locking nut is screwed on the insulating rod at the lower side of the top plate to tighten the resistor sheet mounted on the insulating rod.

9. A switching device, comprising a starting resistor, characterized in that: The starting resistor is the starting resistor according to any one of claims 1 to 8.

10. A switch device according to claim 9, characterized in that: The invention comprises a main bus arranged horizontally, wherein the main bus is connected with a parallel branch, a bypass switch is connected in series to the upper parallel branch, a starting resistor is connected in series to the lower parallel branch, and a current transformer is connected in series to the parallel branch.

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