CN220209968U - Neutral point grounding protection device and motor opposite-dragging test system - Google Patents

Abstract

The utility model discloses a neutral point grounding protection device and a motor opposite-dragging test system, wherein the neutral point grounding protection device comprises: three circuits, a first conductive connection, and a second conductive connection; the circuit comprises a capacitor and a resistor which are arranged in parallel; the first ends of the circuits are electrically connected with the first conductive connecting piece, and the second ends of the three circuits are converged to the second conductive connecting piece; the first conductive connecting piece is used for being connected to a three-phase circuit of the converter network side, and the second conductive connecting piece is used for being connected to a lightning protection total grounding structure of the converter network side. The neutral point grounding protection device can simulate the neutral point grounding of the step-up transformer in a motor opposite-dragging test system, so that the influence on the converter is avoided; the neutral point ground protection device has the advantages of simple structure, low cost and simple assembly, and is beneficial to reducing the volume of the neutral point ground protection device, so that the neutral point ground protection device is small and portable.

Description

Neutral point grounding protection device and motor opposite-dragging test system

Technical Field

The utility model relates to the technical field of a pair-drag test, in particular to a neutral point grounding protection device and a motor pair-drag test system.

Background

With the increasing demand for power in the wind power industry, megawatt-level wind power generation supporting equipment such as a step-up transformer, a converter, a wind driven generator and the like is also developed towards diversification and high power, so that the demand for the generator-motor opposite-dragging test is also increased gradually.

The step-up transformer matched with the converter in the wind power plant generally adopts a grounding mode that a neutral point is grounded. However, in a motor-to-motor-driven test (generator-motor-to-motor-driven test) in a motor plant, there are two cases where the neutral point of the associated step-up transformer grounding system is grounded and the neutral point is not grounded. In motor pair-drawing tests of motor factories, when a step-up transformer is a neutral point ungrounded system, a converter matched with the step-up transformer can be affected.

When the step-up transformer is a neutral point ungrounded system, the influence on the converter is mainly: the three-phase voltage on the grid side of the converter is in a suspended state relatively, and the voltage of the three-phase voltage on the grid side of the converter relative to the ground is unbalanced, so that the voltage of a certain phase on the grid side of the converter relative to the ground is easily overhigh and exceeds the rated value of the lightning protection device on the grid side of the converter, the lightning protection device is broken down, and the upper computer of the converter reports the consequences such as fault, shutdown and the like; the current transformer has high voltage relative to the ground, so that the existing electric gap cannot meet the requirement and arcing discharge occurs.

In summary, how to simulate the neutral point of the step-up transformer to be grounded in the motor pair-pull test system to avoid affecting the current transformer is a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the present utility model is to provide a neutral point grounding protection device and a motor-to-drag test system, in which the neutral point grounding of a step-up transformer is simulated to avoid affecting a current transformer.

In order to achieve the above purpose, the present utility model provides the following technical solutions:

a neutral point ground protection device comprising: a circuit, a first conductive connection, and a second conductive connection;

wherein the circuit comprises a capacitor and a resistor which are arranged in parallel; the first end of the circuit is used for being connected with a three-phase circuit on the grid side of the converter through the first conductive connecting piece, and the second end of the circuit is used for being connected with a lightning protection total grounding structure on the grid side of the converter through the second conductive connecting piece.

Optionally, the neutral point ground protection device further includes a housing, the circuit is located inside the housing, the first conductive connection is located at least partially outside the housing, and the second conductive connection is located at least partially outside the housing.

Optionally, the housing comprises: a circuit mounting board, a first frame, and a second frame;

the circuit mounting plate, the first frame and the second frame are fixedly connected to form a closed cavity, and the circuit is arranged on the circuit mounting plate.

Optionally, the resistor is disposed on the circuit mounting board through a resistor mounting board, the capacitor is distributed on one side of the resistor mounting board, and the resistor is distributed on the other side of the resistor mounting board.

Optionally, the first end of the capacitor and the first end of the resistor are connected in parallel to a first connection row, and the first connection row is electrically connected with the first conductive connection piece;

the second end of the capacitor and the second end of the resistor are connected in parallel to a second connection row, and the second connection row is electrically connected with the second conductive connecting piece;

the first connecting row and the second connecting row are both arranged on the resistor mounting plate in an insulating mode.

Optionally, one of the first connection row and the second connection row and the resistor are located on the same side of the resistor mounting board, and the other resistor is disposed at one end of the resistor mounting board away from the circuit mounting board.

Optionally, the capacitor and the resistor are electrically connected with the first connection row through conductive cables, the capacitor and the resistor are electrically connected with the second connection row through conductive cables, and the first conductive connecting piece and the second conductive connecting piece comprise conductive cables;

wherein, the resistance mounting panel is provided with the first ligature structure that is used for the ligature conductive cable, the casing is provided with the second ligature structure that is used for the ligature conductive cable.

Optionally, the first frame is L-shaped, and the second frame is "u" -shaped;

and/or the circuit mounting board is positioned at the bottom ends of the first frame and the second frame;

and/or the circuit mounting plate is detachably and fixedly connected with the first frame, the circuit mounting plate is detachably and fixedly connected with the second frame, and the first frame is detachably and fixedly connected with the second frame;

and/or, the neutral point grounding protection device further comprises an insulating piece, and the insulating piece is arranged on the outer side of the circuit mounting plate.

Optionally, each of the first conductive connecting piece and the second conductive connecting piece includes a connection terminal and a conductive cable electrically connected to the connection terminal; the connecting terminal is located outside the shell, and the conductive cable is located inside the shell.

Optionally, a heat dissipation structure is arranged in the shell close to the shell plate of the resistor and the capacitor;

and/or a handle is arranged outside the shell;

and/or the shell is provided with a fixing structure for fixing on a mounting surface.

Based on the neutral point grounding protection device, the utility model also provides a motor opposite-dragging test system, which comprises: a converter grid side, a step-up transformer electrically connected to the converter grid side, and the neutral point ground protection device of any one of the above.

Optionally, the neutral point ground protection device is located in a converter cabinet of the converter.

Optionally, the neutral point ground protection device is located outside the converter cabinet of the converter.

In the neutral point grounding protection device provided by the utility model, a circuit comprises a capacitor and a resistor which are arranged in parallel; the first end of each circuit is electrically connected with a first conductive connecting piece, and the first conductive connecting piece is used for being connected with a three-phase circuit at the grid side of the current transformer; the second ends of the three circuits are converged to a second conductive connecting piece, and the second conductive connecting piece is used for being connected to a lightning protection total grounding structure at the grid side of the converter. The neutral point grounding protection device can simulate the neutral point grounding of the step-up transformer in a motor opposite-dragging test system because the step-up transformer is electrically connected with the grid side of the converter, thereby avoiding influencing the converter.

Meanwhile, in the neutral point grounding protection device provided by the utility model, the circuits comprise the capacitors and the resistors which are arranged in parallel, the first end of each circuit is electrically connected with the first conductive connecting piece, and the second ends of the three circuits are converged to the second conductive connecting piece, so that the neutral point grounding protection device has simpler structure, lower cost and simpler assembly, and is also beneficial to reducing the volume of the neutral point grounding protection device; the first conductive connecting piece is used for being connected into a three-phase circuit of the converter network side, and the voltage withstand level of the neutral point grounding protection device is reduced due to the fact that the voltage of the converter network side is low, so that the size of the neutral point grounding protection device is reduced, and the neutral point grounding protection device is small and portable.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present utility model, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a neutral point ground protection device access motor pair-towing test system according to an embodiment of the present utility model;

fig. 2 is a schematic structural diagram of a neutral point ground protection device according to an embodiment of the present utility model;

FIG. 3 is an exploded view of a neutral point ground protection device according to an embodiment of the present utility model;

fig. 4 is a schematic structural diagram of a neutral point ground protection device in a converter cabinet according to an embodiment of the present utility model;

fig. 5 is a schematic structural diagram of a neutral point ground protection device according to an embodiment of the present utility model located outside a converter cabinet.

In fig. 1-5:

001 is a neutral point grounding protection device, 002 is a converter net side, 003 is a step-up transformer, and 004 is a lightning protection total grounding structure;

1 is a first conductive connecting piece, 2 is a second conductive connecting piece, 3 is a capacitor, 4 is a resistor, 5 is a shell, 501 is a first frame, 502 is a second frame, 503 is a circuit mounting plate, 6 is a handle, 7 is a wiring terminal, 8 is a heat dissipation structure, 9 is a fixed structure, 10 is an insulating piece, 11 is a resistor mounting plate, 12 is an insulating connecting piece, 13 is a first connecting row, 14 is a second connecting row, 15 is a first binding structure, 16 is a second binding structure, 17 is a converter cabinet, 18 is a first connecting part, and 19 is a second connecting part.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include, for example, "one or more" such forms of expression, unless the context clearly indicates to the contrary. It should also be understood that in embodiments of the present application, "one or more" means one, two, or more than two; "and/or", describes an association relationship of the association object, indicating that three relationships may exist. The character "/" generally indicates that the context-dependent object is an "or" relationship.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

The plurality of the embodiments of the present application refers to greater than or equal to two. It should be noted that, in the description of the embodiments of the present application, the terms "first," "second," and the like are used for distinguishing between the descriptions and not necessarily for indicating or implying a relative importance, or alternatively, for indicating or implying a sequential order.

Reference to "vertical" in this application is to "substantially vertical" in actual operation. Substantially vertical "is understood to mean vertical with some error.

As shown in fig. 1, the neutral point ground protection device 001 provided in the embodiment of the present utility model includes: a circuit, a first conductive connection 1, and a second conductive connection 2.

In the neutral point ground protection device 001, the circuit includes a capacitor 3 and a resistor 4 arranged in parallel, and it is understood that the circuit includes a parallel branch including the capacitor 3 and the resistor 4 arranged in parallel.

To facilitate the parallel connection of the capacitor 3 and the resistor 4, the first end of the capacitor 3 and the first end of the resistor 4 may be selectively connected in parallel to the first connection row 13, and the first connection row 13 and the first conductive connection 1 are electrically connected; a second terminal of the capacitor 3 and a second terminal of the resistor 4 are connected in parallel to the second connection line 14, and the second connection line 14 is electrically connected to the second conductive connection 2.

The first connection row 13 and the second connection row 14 may be copper bars or other structures, which are not limited in this embodiment.

In practical situations, the capacitor 3 and the resistor 4 may alternatively be connected in parallel through other ways, and are not limited to the above-mentioned structure.

In the neutral point ground protection device 001, the first end of the circuit is used for being connected to the three-phase circuit of the grid side 002 of the current transformer through the first conductive connecting piece 1, that is, the first end of the circuit is electrically connected to the first conductive connecting piece 1, and the first conductive connecting piece 1 is used for being connected to the three-phase circuit of the grid side 002 of the current transformer. It will be appreciated that the first conductive connection 1 is intended to be electrically connected to a three-phase circuit on the grid side 002 of the current transformer.

Since the first end of the circuit needs to be connected to the three-phase circuit of the grid side 002 of the current transformer, the circuit includes: three parallel branches corresponding to three phases in the three-phase circuit of the converter network side 002 one by one. It will be appreciated that the first connection rows 13 are in one-to-one correspondence with the parallel branches.

In order to facilitate the first conductive connection piece 1 to access to the three-phase circuit of the grid side 002 of the current transformer, three first conductive connection pieces 1 can be selected, and the three first conductive connection pieces 1 are in one-to-one correspondence with the three circuits. Thus, one first conductive connection member 1 is electrically connected to the a phase of the three-phase circuit of the current transformer mesh side 002, one first conductive connection member 1 is electrically connected to the B phase of the three-phase circuit of the current transformer mesh side 002, and the other first conductive connection member 1 is electrically connected to the C phase of the three-phase circuit of the current transformer mesh side 002.

The three first conductive connections 1 may be relatively independent, i.e. the three first conductive connections 1 are three parts; alternatively, three first conductive connectors 1 are integrated into one component by means of insulated connectors.

In the neutral point ground protection device 001, the second end of the circuit is connected to the lightning protection total ground structure 004 of the converter network side 002 through the second conductive connecting piece 2. It will be appreciated that the second end of the circuit is electrically connected to the second conductive connector 2, and that the second conductive connector 2 is adapted to be connected to the lightning protection total ground structure 004 of the grid side 002 of the current transformer, i.e. the second conductive connector 2 is adapted to be electrically connected to the lightning protection total ground structure 004 of the grid side 002 of the current transformer.

In the circuit, three parallel branches corresponding to three phases in the three-phase circuit of the converter network side 002 are converged to the second conductive connecting piece 2. In the case of providing the second connection line 14, three parallel branches of the selectable circuit, which correspond one-to-one to three phases of the three-phase circuit of the converter grid side 002, are connected to the second connection line 14.

Since the second connection row 14 merges three parallel branches, there may be one in the second connection row 14. Of course, it is also possible to select three second connection rows 14 and three second connection rows 14 are electrically connected.

In the above circuit, the capacitor 3 and/or the resistor 4 may be added according to actual situations, for example, the number of the resistors 4 is increased in the circuit, and all the resistors 4 in the circuit are connected in series and then connected in parallel with the capacitor 3; for example, the number of capacitors 3 is increased in the circuit, and any two capacitors 3 are arranged in parallel. Of course, the alternative circuit may also include other electronic components. The circuit provided in this embodiment is not limited to only including the capacitor 3 and the resistor 4 arranged in parallel, as long as it is ensured that the step-up transformer in the motor pair-pull test system can be simulated to be grounded.

The circuit comprises three parallel branches corresponding to three phases in the three-phase circuit of the converter network side 002 one by one, and the number of the capacitor 3 and the resistor 4 is at least three. In order to facilitate the parallel connection of the capacitor 3 and the resistor 4, the distribution direction of any two capacitors 3 and the distribution direction of any two resistors 4 can be selected to be the same. In the case that the number of the first connection rows 13 is three, the distribution direction of any two first connection rows 13 and the distribution direction of any two resistors 4 may be selected to be the same, that is, the distribution direction of any two first connection rows 13 and the distribution direction of any two capacitors 3 are the same. In the case where the second connection line 14 is one, the longitudinal direction of the second connection line 14 is the distribution direction of any two capacitors 3 and the distribution direction of any two resistors 4.

It should be noted that the first end and the second end of the circuit are two ends of the circuit respectively, the two ends of the circuit are two ends of the capacitor 3 and two ends of the resistor 4, that is, the first end of the circuit includes the first end of the capacitor 3 and the first end of the resistor 4, and the second end of the circuit includes the second end of the capacitor and the second end of the resistor 4.

In practical applications, the optional circuit may further include other parallel branches, which are not limited to three parallel branches corresponding to three phases of the three-phase circuit on the grid side 002 of the current transformer.

When the motor stops running the drag test system, the discharging of the charge energy of the capacitor 3 is completed through the resistor 4, so that the damage of the residual charge in the capacitor 3 to the human body is avoided.

In the motor pair-drag test system, the three-phase circuit of the inverter network side 002 and the low-voltage side of the step-up transformer 003 are electrically connected. In this way, the neutral point of the low-voltage side of the step-up transformer 003 is grounded through the first conductive connecting piece 1, the circuit and the second conductive connecting piece 2, namely, the neutral point of the step-up transformer 003 is simulated to be grounded in a motor opposite-dragging test system, the voltage of the three-phase voltage of the converter network side 002 relative to the ground is balanced, the probability that the voltage of the converter network side 002 relative to the ground is too high is reduced, the probability that the voltage of the converter network side 002 relative to the ground exceeds the rated value of the lightning protection device of the converter network side 002 is also reduced, and therefore the probability that the lightning protection device of the converter network side 002 is broken down is reduced, and the probability that a fault is reported by an upper computer of the converter is reduced; in addition, the three-phase voltage of the current transformer network side 002 is balanced with respect to the ground voltage, so that the arcing discharge phenomenon caused by the fact that the existing electric gap cannot meet the requirement is avoided.

Therefore, in the motor opposite-dragging test system, when the step-up transformer 003 is a neutral point ungrounded system, the neutral point grounding protection device 001 simulates the neutral point grounding of the step-up transformer 003, reduces the risk of damaging the lightning protection device of the converter network side 002, and also reduces the probability of potential safety hazards such as arc discharge phenomenon and the like of the converter network side 002, thereby avoiding influencing the converter.

The neutral point grounding protection device has the advantages of simpler structure, lower cost and simpler assembly, and is beneficial to reducing the volume of the neutral point grounding protection device 001; the first conductive connecting piece 1 is used for being connected into a three-phase circuit of the converter network side 002, and the voltage withstand level of the neutral point grounding protection device 001 is reduced due to the fact that the voltage of the converter network side 002 is low, so that the size of the neutral point grounding protection device 001 is reduced, and the neutral point grounding protection device 001 is small and portable.

In some embodiments, as shown in fig. 2, the neutral grounding protection apparatus 001 further includes a housing 5. Wherein the electrical circuit is located inside the housing 5, the first conductive connector 1 is located at least partially outside the housing 5, and the second conductive connector 2 is located at least partially outside the housing 5.

Alternatively, on the one hand, the first conductive connection 1 may be located only partially outside the housing 5; on the other hand, the entire first conductive connector 1 is located outside the housing 5.

Correspondingly, on the one hand, the second conductive connection 2 is only partially located outside the housing 5; on the other hand, the entire second conductive connector 2 is located outside the housing 5.

In order to facilitate the use of the neutral point ground protection device, the first conductive connecting piece 1 and the second conductive connecting piece 2 may each comprise a connection terminal 7 and a conductive cable electrically connected to the connection terminal 7; wherein the connection terminal 7 is located outside the housing 5, and the conductive cable is located inside the housing 5. Thus, the connection terminal 7 of the first conductive connecting piece 1 can be connected to the three-phase circuit of the converter network side 002 through a cable, and the connection terminal 7 of the second conductive connecting piece 2 can be connected to the lightning protection total grounding structure 004 of the converter network side 002 through a cable.

In the case where the number of the first conductive connecting members 1 is three and the number of the second conductive connecting members 2 is one, the number of the connection terminals 7 is four.

As for the type of the connection terminal 7, this embodiment is not limited, and is selected according to actual circumstances.

In order to facilitate the installation of the neutral ground protection 001, the terminals 7 may alternatively be located on top of the housing 5. Of course, the connection terminal 7 may be located at other positions of the housing 5, which is not limited in this embodiment.

According to the neutral point grounding protection device 001, the shell 5 is arranged, and the circuit is accommodated through the shell 5, namely, the circuit is integrated in the shell 5, so that the integration degree of the neutral point grounding protection device 001 is improved, the size of the neutral point grounding protection device 001 is reduced, and the neutral point grounding protection device 001 is small and portable; and is also beneficial to the protection of the circuit.

In practical situations, the relative positional relationship between the circuit and the housing 5 may be other, or the neutral point ground protection apparatus 001 does not include the housing 5, and is not limited to the above embodiment.

As for the specific structure and specific shape of the housing 5, this embodiment is not limited thereto, as selected according to actual circumstances.

In the working process of the neutral point grounding protection device, the capacitor 3 and the resistor 4 generate heat, and in order to ensure that the capacitor 3 and the resistor 4 work normally, the capacitor 3 and the resistor 4 are required to dissipate heat. In some embodiments, to improve heat dissipation, a heat dissipation structure 8 may be optionally provided in the housing 5 adjacent to the housing plate of the resistor 4 and capacitor 3.

The heat dissipation structure 8 may be a heat dissipation mesh, a heat dissipation fin, a heat dissipation fan or other structures, which is not limited in this embodiment.

The outside of the housing 5 is provided with a handle 6. In this way, the handle 6 can be carried to carry the whole neutral point ground protection apparatus 001, so that the neutral point ground protection apparatus 001 is convenient to carry and transport. The type and number of the handles 6 are selected according to the actual situation, and this embodiment is not limited thereto.

The handle 6 may be disposed at the top of the housing 5, or may be disposed at two sides of the housing 5, and the specific position of the handle 6 is not limited in this embodiment.

The neutral point ground protection device 001 may be directly placed on the mounting surface or may be fixed to the mounting surface. For improved stability, the neutral ground protection 001 may be optionally secured to the mounting surface, i.e., the housing 5 is adapted to be secured to the mounting surface. In order to facilitate the fixing of the housing 5, the housing 5 is provided with a fixing structure 9 for fixing to a mounting surface. The fixing structure 9 may be a fixing hole or other structures, which is not limited in this embodiment.

The mounting surface may be a ground surface or a bottom surface of a certain cavity, which is not limited in this embodiment.

In some embodiments, to facilitate mounting of the circuit, as shown in fig. 2 and 3, the housing 5 includes: a circuit mounting board 503, a first frame 501, and a second frame 502.

Wherein the circuit mounting board 503, the first frame 501 and the second frame 502 are fixedly connected to form a closed cavity. It should be noted that the closed cavity may be a closed structure or a non-closed structure. The non-containment structure may be a venting structure. The type of the closed cavity is selected according to practical situations, and the embodiment is not limited to this.

In order to improve the stability, the circuit mounting board 503 is fixedly connected to the first frame 501, the circuit mounting board 503 is fixedly connected to the second frame 502, and the first frame 501 is fixedly connected to the second frame 502. For easy disassembly and maintenance, the circuit mounting board 503 is detachably and fixedly connected to the first frame 501, the circuit mounting board 503 is detachably and fixedly connected to the second frame 502, and the first frame 501 is detachably and fixedly connected to the second frame 502.

The specific manner of detachably and fixedly connecting is selected according to practical situations, and the detachably and fixedly connecting is realized by, for example, a threaded connector or a clamping structure, which is not limited in this embodiment.

In the above embodiments, the circuit is located in the closed cavity, and the circuit is disposed on the circuit mounting board 503. It will be appreciated that both the capacitor 3 and resistor 4 of the circuit are provided on the circuit mounting board 503. Thus, during the assembly process, the capacitor 3 and the resistor 4 may be disposed on the circuit board 503, and then the circuit board 503, the first frame 501, and the second frame 502 may be fixedly connected.

The bottom of the capacitor 3 is more easily discharged to ground or other conductors. In order to avoid the above problem, since the capacitor 3 is disposed on the circuit mounting board 503, the optional neutral grounding protection apparatus 001 further includes an insulating member 10, and the insulating member 10 is disposed outside the circuit mounting board 503.

It will be appreciated that the outside of the circuit mounting board 503 is the side of the circuit mounting board 503 that is remote from the enclosed cavity. The insulator 10 may be an insulating plate or an insulating film, and the present embodiment is not limited thereto.

In the above embodiment, the capacitor 3 is directly provided on the circuit mounting board 503 or the capacitor 3 is indirectly provided on the circuit mounting board 503; the resistor 4 is directly provided on the circuit mounting board 503 or the resistor 4 is indirectly provided on the circuit mounting board 503.

As shown in fig. 3, the resistor 4 is provided on the circuit board 503 via the resistor board 11. In this case, the resistor 4 is indirectly provided on the circuit board 503, and the capacitor 3 is directly provided on the circuit board 503. The capacitor 3 is distributed on one side of the resistor mounting plate 11 and the resistor 4 is distributed on the other side of the resistor mounting plate 11.

In the above structure, in order to facilitate heat dissipation, the board in the first frame 501 near the resistor 4 may be optionally provided with the above heat dissipation structure 8, and the board in the second frame 502 near the capacitor 3 may be provided with the above heat dissipation structure 8.

In the case where the capacitor 3 and the resistor 4 are connected in parallel through the first connection line 13 and the second connection line 14, in order to facilitate the parallel connection of the capacitor 3 and the resistor 4 and to reduce the circuit mounting board 503, the first connection line 13 and the second connection line 14 may be selected to be disposed on the resistor mounting board 11 in an insulating manner. It will be appreciated that the first connection row 13 and the second connection row 14 are each connected with insulation to the resistor mounting board 11. In this way, the resistor mounting board 11 is fully utilized, so that the occupation of the circuit mounting board 503 is reduced, and the circuit mounting board 503 is reduced, which is beneficial to reducing the whole housing 5.

For the specific manner in which the first connection row 13 and the second connection row 14 are arranged on the resistor mounting plate 11 in an insulating manner, for example, the first connection row 13 and the second connection row 14 are arranged on the resistor mounting plate 11 in an insulating manner through the insulating connecting piece 12, one end of the insulating connecting piece 12 is fixed on the resistor mounting plate 11, and the first connection row 13 and the second connection row 14 are fixedly connected with the other end of the insulating connecting piece 12. The insulating connector 12 may be an insulated stud or other component, which is not limited in this embodiment.

It should be noted that, in the case that the number of the first connection rows 13 is three and the number of the second connection rows 14 is one, the number of the insulating connection members 12 is at least four, at least one insulating connection member 12 corresponds to one first connection row 13, and at least one insulating connection member 12 corresponds to one second connection row 14.

In order to facilitate the electrical connection of the capacitor 3, the resistor 4, the first connection row 13 and the second connection row 14, on the one hand, the first connection row 13 and the resistor 4 may be selected to be located on the same side of the resistor mounting board 11, and the second connection row 14 may be disposed at an end of the resistor mounting board 11 away from the circuit mounting board 503; alternatively, the first connection row 13 may be disposed at an end of the resistor mounting board 11 remote from the circuit mounting board 503, and the second connection row 14 and the resistor 4 may be disposed on the same side of the resistor mounting board 11. In this way, the resistor mounting board 11 can be reduced, the space in the direction perpendicular to the circuit mounting board 503 can be fully utilized, the entire housing 5 can be further reduced, and the miniaturization of the neutral point ground protection device is facilitated.

In practical applications, the first connection row 13 and the second connection row 14 may be located on the same side of the resistor mounting board 11 as the resistor 4, or the first connection row 13 and the second connection row 14 may be distributed in other ways, which is not limited in this embodiment.

In some embodiments, the selectable capacitor 3 and the resistor 4 are each electrically connected to the first connection row 13 by a conductive cable, and the capacitor 3 and the resistor 4 are each electrically connected to the second connection row 14 by a conductive cable, and the first conductive connector 1 and the second conductive connector 2 each comprise a conductive cable. To facilitate routing, the selectable resistance mounting plate 11 is provided with a first lashing structure 15 for lashing conductive cables, and the housing 5 is provided with a second lashing structure 16 for lashing conductive cables.

For the specific location of the first ligating structure 15, it is practical to select, for example, that the first ligating structure 15 is located on both sides of the resistor mounting plate 11, with both sides of the first ligating structure 15 being adjacent to the side of the resistor 4.

The first binding structure 15 may be a hole or other structure such as a tie button that may be stamped out of the resistor mounting plate 11.

The number and distribution of the first ligating structures 15 are selected according to the actual circumstances, and the present embodiment is not limited thereto.

The particular location of the second ligating structure 16 may be selected as practical, for example, with the second ligating structure 16 being located on an inner side wall of the second frame 502.

The second ligature structure 16 may be a hole or other structure such as a tie button which may be obtained by punching out the housing 5.

The number and distribution of the second ligating structures 16 is selected according to the circumstances, and this is not limiting in this embodiment.

In some embodiments, the first frame 501 is L-shaped and the second frame 502 is U-shaped. Of course, the first frame 501 may alternatively have a U-shape, and the second frame 502 may have an L-shape. Thus, the first frame 501 and the second frame 502 may enclose a housing structure having an opening at one end, the circuit mounting board 503 closes the opening of the housing structure to form a closed cavity, and the housing 5 has a rectangular parallelepiped shape or a square shape.

The above structure can reduce the material consumption of the first frame 501 and the second frame 502, simplify the installation and disassembly of the whole housing 5, and facilitate the maintenance of the whole device.

The first frame 501 is L-shaped, which means that the first frame 501 is L-shaped under a certain viewing angle; the second frame 502 has a U shape, which means that the second frame 502 has a U shape under a certain view angle. The present embodiment is not limited to the above-described view angle.

In the above embodiment, the circuit mounting board 503 may be a flat board or other shape, and is selected according to practical situations.

In other embodiments, the first frame 501 and the second frame 502 may be selected to have other shapes, and are not limited to the above embodiments.

In the neutral point ground protection device, the relative positional relationship among the circuit mounting board 503, the first frame 501, and the second frame 502 is selected according to the actual situation. To improve stability, a circuit mounting board 503 may be optionally located at the bottom ends of the first frame 501 and the second frame 502. In this case, the insulating member 10 is located at the bottom end of the circuit mounting board 503, and the fixing structure 9 may be disposed at the circuit mounting board 503, and/or the first frame 501, and/or the second frame 502. When the fixing structure 9 is disposed on the first frame 501, the first frame 501 has a folded edge, and the fixing structure 9 is disposed on the folded edge; when the fixing structure 9 is disposed on the second frame 502, the second frame 502 has a folded edge, and the fixing structure 9 is disposed on the folded edge.

In the above structure, the capacitor 3 is located on top of the circuit board 503, the resistor board 11 is located on top of the circuit board 503, and the resistor board 11 is optionally perpendicular to the circuit board 503. The first connection row 13 is located at the bottom end of the resistor 4, and the second connection row 14 is located at the top end of the resistor mounting board 11.

In the above-described configuration, when the first frame 501 is L-shaped and the second frame 502 is "u" -shaped, one plate of the first frame 501 forms the top plate of the housing 5, and the other plates of the first frame 501 and the second frame 502 form four side plates of the housing 5.

In practical cases, the circuit mounting board 503 may be located at other positions of the first frame 501 and the second frame 502, and is not limited to the above embodiment.

Based on the neutral point ground protection device 001 provided in the above embodiment, the embodiment of the present utility model further provides a motor pair-towing test system, which includes: a step-up transformer 003 electrically connected to the converter grid 002, and the neutral point ground protector 001 described in the above embodiment.

The grid side 002 of the current transformer is the grid side of the current transformer. The converter has a converter grid side 002 and a converter side.

In order to facilitate installation of the neutral point ground protection 001, a first connection portion 18 for accessing the first conductive connection member 1 and a second connection portion 19 for accessing the second conductive connection member 2 are reserved in the converter cabinet 17 of the converter grid side 002.

The neutral point ground protector 001 has a small volume, and the neutral point ground protector 001 may be located inside or outside the converter cabinet 17 of the converter.

When the space on the grid side 002 of the current transformer is sufficient and can satisfy the electrical safety regulations, as shown in fig. 4, the neutral point ground protection device 001 may be disposed inside the current transformer cabinet 17 of the current transformer, in which case the mounting surface may be the inner bottom wall of the current transformer cabinet 17. When the space on the grid side 002 of the current transformer is insufficient or sufficient electrical clearance cannot be ensured, as shown in fig. 5, the neutral point ground protection 001 may be disposed outside the current transformer cabinet 17, for example, the neutral point ground protection 001 is disposed on the ground outside the current transformer cabinet 17, in which case the mounting surface may be the ground. In this way, the neutral point grounding protection device 001 can be compatible with the internal and external use modes of the converter cabinet 17, and the use of the neutral point grounding protection device 001 is facilitated.

Because the neutral point ground protection device 001 provided in the above embodiment has the above technical effects, the above motor pair-towing test system includes the above neutral point ground protection device 001, and the above motor pair-towing test system also has corresponding technical effects, which are not described herein again.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (13)

1. A neutral point ground protection device, comprising: a circuit, a first conductive connection, and a second conductive connection;

wherein the circuit comprises a capacitor and a resistor which are arranged in parallel; the first end of the circuit is used for being connected with a three-phase circuit on the grid side of the converter through the first conductive connecting piece, and the second end of the circuit is used for being connected with a lightning protection total grounding structure on the grid side of the converter through the second conductive connecting piece.

2. The neutral point ground protection device of claim 1, further comprising a housing, the circuit being located inside the housing, the first conductive connection being located at least partially outside the housing, the second conductive connection being located at least partially outside the housing.

3. The neutral point ground protection device of claim 2, wherein the housing comprises: a circuit mounting board, a first frame, and a second frame;

the circuit mounting plate, the first frame and the second frame are fixedly connected to form a closed cavity, and the circuit is arranged on the circuit mounting plate.

4. A neutral point ground protection device as defined in claim 3, wherein the resistor is disposed on the circuit mounting plate by a resistor mounting plate, the capacitance being distributed on one side of the resistor mounting plate and the resistor being distributed on the other side of the resistor mounting plate.

5. The neutral point ground protection device of claim 4, wherein,

the first end of the capacitor and the first end of the resistor are connected in parallel to a first connection row, and the first connection row is electrically connected with the first conductive connecting piece;

the second end of the capacitor and the second end of the resistor are connected in parallel to a second connection row, and the second connection row is electrically connected with the second conductive connecting piece;

the first connecting row and the second connecting row are both arranged on the resistor mounting plate in an insulating mode.

6. The neutral point ground protection device of claim 5, wherein one of the first connection row and the second connection row is on a same side of the resistor mounting plate and the other is disposed at an end of the resistor mounting plate remote from the circuit mounting plate.

7. The neutral point ground protection device of claim 5, wherein the capacitor and the resistor are each electrically connected to the first connection row by a conductive cable, the capacitor and the resistor are each electrically connected to the second connection row by a conductive cable, and the first conductive connector and the second conductive connector each comprise a conductive cable;

wherein, the resistance mounting panel is provided with the first ligature structure that is used for the ligature conductive cable, the casing is provided with the second ligature structure that is used for the ligature conductive cable.

8. A neutral point ground protection device as defined in claim 3, characterized in that,

the first frame is L-shaped, and the second frame is U-shaped;

and/or the circuit mounting board is positioned at the bottom ends of the first frame and the second frame;

and/or the circuit mounting plate is detachably and fixedly connected with the first frame, the circuit mounting plate is detachably and fixedly connected with the second frame, and the first frame is detachably and fixedly connected with the second frame;

and/or, the neutral point grounding protection device further comprises an insulating piece, and the insulating piece is arranged on the outer side of the circuit mounting plate.

9. The neutral point ground protection device of claim 2, wherein the first and second conductive connectors each comprise a terminal and a conductive cable electrically connected to the terminal; the connecting terminal is located outside the shell, and the conductive cable is located inside the shell.

10. The neutral point ground protection device of claim 2, wherein,

a heat dissipation structure is arranged in the shell, close to the shell plate of the resistor and the capacitor;

and/or a handle is arranged outside the shell;

and/or the shell is provided with a fixing structure for fixing on a mounting surface.

11. A motor pair-drag test system, comprising: a converter grid side, a step-up transformer electrically connected to the converter grid side, and a neutral point ground protection device according to any one of claims 1-10.

12. The motor pair drag test system of claim 11, wherein the neutral point ground protection device is located within a converter cabinet of a converter.

13. The motor pair drag test system of claim 11, wherein the neutral point ground protection device is located outside a converter cabinet of the converter.