Combined ground and protection device for modular converters

Abstract

The invention relates to a combined grounding and protection device for a modular voltage and power converter for converting a primary alternating voltage having one or more phases into a secondary voltage. The combined grounding and protection device comprises a plurality of input contacts and a plurality of output contacts, and the plurality of output contacts and the plurality of output contacts are conductively connected with the voltage input ends and the voltage output ends of the single modules of the converter. An input contact and an output contact connected to the same single module are connected to a variable resistor that becomes conductive when a droop voltage across the variable resistor exceeds a first threshold. An electrically non-conductive switching bar having a bridge contact can be moved from an operating position to a ground position. In the ground position, the bridge contact connects the input and output contacts of the single module to each other and to the ground terminal. In the working position, the same input and output contacts are not connected through the bridge contact and are not connected with the grounding terminal.

Description

Technical Field

[0001] The invention relates to a combined grounding and protection device for a modular voltage and power converter for converting a primary AC voltage having one or more phases into a secondary voltage. The modular voltage and power converter comprises a plurality of single modules to be connected in series for each phase of the primary AC voltage. Each single module has a voltage input and a voltage output for receiving a phase of the primary AC voltage. Background Art

[0002] In certain applications, a modularly constructed voltage and power converter in the form of a solid-state transformer (SST), also referred to as a power electronic transformer, is intended to replace the function of a conventional 50 Hz oil or molded resin transformer, for example, in order to convert a three-phase high voltage into a DC voltage. For this purpose, the power electronic transformer is constructed from a plurality of single converters, wherein for each phase of the high voltage, a plurality of single converters are connected in series and the series-connected single converters are in turn connected in parallel as a whole.

[0003] The single converters, also called cells, are at high potential during normal operation and are therefore not accessible to personnel. If maintenance or other work still needs to be carried out on the SST, different safety regulations must be observed. In particular, it must be ensured that they are voltage-free and the grounding fittings must be switched for each cell so that each cell is grounded. Due to the large number of individual cells that comprise the SST, the preparation work before maintenance is very complex and time-consuming.

[0004] Furthermore, problems may arise when each cell can no longer conduct current due to a fault in the cell, since in this case a high conductor-conductor voltage of, for example, 20 kV drops at the separation point, which may, for example, lead to explosive damage to the cell. Furthermore, the debris of the explosively damaged cell may damage other cells arranged adjacently, so that the damage is not limited to a single cell. Summary of the invention

[0005] Against this background, the task facing the person skilled in the art is to provide a device with which at least some of the problems described above can be solved.

[0006] The invention achieves this object by means of a combined grounding and protection device according to claim 1. Preferred embodiments of the combined grounding and protection device are the subject matter of the dependent claims.

[0007] According to a first aspect, a combined grounding and protection device for a voltage and power converter of modular construction is provided, the voltage and power converter being used to convert a primary AC voltage having one or more phases into a secondary voltage. The voltage and power converter comprises a plurality of single modules to be connected in series for each phase of the primary AC voltage. In order to receive the phase of the primary voltage, each single module has a voltage input and a voltage output. The combined grounding and protection device comprises a plurality of input contacts and a plurality of output contacts, wherein the input contacts and the output contacts are configured so that each input contact can be conductively connected to the voltage input of the single module of the voltage and power converter, and each output contact can be conductively connected to the voltage output of the single module of the voltage and power converter. In addition, each input contact and output contact that can be connected to the voltage input and voltage output of the same single module are connected by means of a variable resistor. The variable resistor is configured to conductively connect the input contact to the output contact when the voltage dropped on the variable resistor exceeds a first threshold value. The combined grounding and protection device also comprises a non-conductive switching bar having a plurality of bridge contacts. The switching bar is configured to move from a working position to a grounding position. When the switching bar is in the grounding position, each of the plurality of bridge contacts connects the input contact to the output contact in a conductive manner, and can be connected to the voltage input terminal and the voltage output terminal of the same single module. In addition, the input contact and the output contact conductively connected through the bridge contact are connected to the grounding terminal. When the switching bar is in the working position, the input contact and the output contact that can be connected to the voltage input terminal and the voltage output terminal of the same single module are not conductively connected through the bridge contact, and the input contact and the output contact are not conductively connected to the grounding terminal.

[0008] Therefore, a device or apparatus is provided which, due to its advantageous structure, assumes three functions at once: it connects the output contacts and input contacts of the cells or single modules of a modular voltage and power converter which are directly successive to each other in a series circuit, thereby connecting the single modules in series, protecting itself from overvoltage via the variable resistance of each single module, and enabling, via the conductive connection of the input contacts and the output contacts, that when the switching bar is in the grounding position, all the single modules connected in series are connected to the grounding terminal via the movement of the switching bar and are thus grounded.

[0009] In other words, the device of the invention comprises a plurality of input and output contacts, each of which is used to contact the corresponding voltage input and voltage output of a single module of the combined voltage and power converter. Therefore, the number of input contacts and the number of output contacts of the grounding and protection device respectively correspond to the number of single monomers. Each pair of input contacts and output contacts is assigned to a single module and is configured to be connected to the voltage input terminal or the voltage output terminal of each single module.

[0010] In an exemplary embodiment, each combined grounding and protection device is provided for grounding and protecting all single modules of a modular voltage and power converter, which are provided for converting phases of a primary AC voltage. Thus, for each phase of the primary AC voltage, a separate combined grounding and protection device is provided. For example, in a modular voltage and power converter for converting a three-phase high voltage into a DC voltage, three groups of single modules are provided, one for each phase, and three combined grounding and protection devices are also provided accordingly.

[0011] In order to protect the single modules from overvoltage, the input and output contacts assigned to the single modules in pairs are respectively connected to a variable resistor. The variable resistor is provided to connect the input contacts and the output contacts to each other in an electrically conductive manner, i.e., to bridge a plurality of single modules when the voltage drop across the variable resistor exceeds a first threshold value. Thus, in the event of a single module failure and the resulting voltage increase between the voltage input and voltage output of the cell or the associated input and output contacts, the variable resistor has the effect of limiting the voltage.

[0012] Furthermore, the combined grounding and protection device comprises a plurality of conductive bridge contacts, which are part of a non-conductive switching strip. The switching strip can be moved between two positions, one of which is referred to as the working position and the other as the grounding position. For example, the movement of the switching strip between the working position and the grounding position can be a translational movement in one direction, that is, the switching strip is displaced from the working position to the grounding position and vice versa.

[0013] When the switching strip is in the grounding position, each of the plurality of bridge contacts connects the input contact to the output contact, wherein the contacts connected to one another are assigned to the same single module. Thus, the bridge contact establishes an electrically conductive connection between the input and output contacts in the grounding position and short-circuits them. The number of bridge contacts thus corresponds to the number of single modules provided with the combined grounding and protection device.

[0014] In order to ground the short-circuited single module, i.e. connect it to the ground, a grounding terminal is also provided. The grounding terminal can be connected to the ground. The combined grounding and protection device is designed so that in the grounding position, the input and output contacts short-circuited by the bridge contact are also connected to the grounding terminal, and thus all the single modules of the combined grounding and protection device are grounded.

[0015] If, on the other hand, the switching strip is moved into the working position or is located in the working position, the bridge contact is moved into a position in which the bridge contact non-conductively connects the input and output contacts to one another, i.e., these input and output contacts are not short-circuited. The grounding terminal is also no longer connected to the input and output contacts, so that these contacts are no longer grounded, i.e., are no longer grounded. The combined grounding and protection device according to the invention thus advantageously provides a possibility by which a single module can be protected from overvoltage and can also be grounded, for example for maintenance purposes.

[0016] In a preferred embodiment of the grounding and protection device, in order to connect the individual modules of the voltage and power converter in series, the output contacts that can be connected to the voltage output of the individual module to be connected in series first are connected to the input contacts by means of current strips, which can be connected to the voltage input of the individual module to be connected in series later. In a preferred embodiment, the grounding and protection device thus also advantageously assumes the series connection of all individual modules that are provided for accommodating the same phase in a modularly constructed voltage and power converter.

[0017] In other words, in a preferred embodiment, the grounding and protection device comprises a plurality of current strips, which can be formed, for example, by conductive metal tracks. In this case, the number of current strips or current tracks is one less than the number of single modules to be protected and grounded by the grounding and protection device. Each current strip connects an output contact of the grounding and protection device to an input contact of the grounding and protection device. In this case, the output contact is conductively connected to the input contact, which is provided for connection to the voltage output and voltage input of the directly successive single modules to be connected in series.

[0018] The bridge contact for grounding a single module can, for example, connect two current strips to each other in an electrically conductive manner in the grounding position of the switching strip, and the two current strips are connected to input contacts and output contacts, and the input contacts and output contacts are respectively provided for connection to the same single module. Therefore, when the modular voltage and power converter is to be grounded, the input and output contacts are short-circuited by the conductive connection of the current strip. In this case, the current strip can also be conductively connected to the ground terminal and thus grounded. For this purpose, for example, an additional current strip can be provided, which is adapted to be connected to the voltage output end of the last single module in the series circuit, and the current strip is electrically connected to the ground terminal in the grounding position of the switching strip, and is electrically separated from the ground terminal in the working position.

[0019] In a preferred embodiment, a spark gap is formed between the input contact and the output contact, which can be connected to the voltage input or voltage output of the same single module, respectively, and is configured so that a voltage flashover occurs when the voltage drop across the spark gap exceeds a second threshold value, wherein the second threshold value is preferably greater than the first threshold value. If, in an extreme fault situation, for example, in the case of a high-voltage insulation breakdown of a single module, the grid voltage drops only across a small number of remaining single modules, and if a variable resistor provided for protecting the single modules fails, the single modules are additionally protected by spark gaps, in which case the voltage drops across the spark gap.

[0020] Preferably, the spark gap is respectively formed between the second end of the current strip connected to the input contact and the first end of the current strip connected to the output contact. Therefore, no additional components need to be provided for the spark gaps. Instead, these spark gaps are advantageously formed by suitable design and arrangement of the current strips that are already provided.

[0021] For connecting the current strip to the bridge contact, a resiliently mounted contact bolt is preferably provided. The contact bolt is preferably fixed in a common support made of a non-conductive material. The resiliently mounted contact bolt can be preloaded, for example, toward the bridge contact so that a reliable contact-making of the bridge contact is achieved when the bridge contact is moved.

[0022] It is further preferred that each current strip includes two contact bolts, which are in contact with the same bridge contact in the working position of the switching strip, and are in contact with different bridge contacts in the grounding position of the switching strip. Therefore, in a preferred embodiment, it is provided that, in normal operation, the bridge contacts starting from the same current strip rest with their contact surfaces on the same bridge contact or contact the bridge contact. Therefore, the contact bolts assigned to the same current strip are not only electrically conductively connected via the current strip in the working position of the switching strip, but also electrically conductively connected via the bridge contacts. In the grounding position of the switching strip, the contact bolts assigned to the same current strip are still only electrically conductively connected via the current strip. Conversely, the contact bolts are connected to other current strips via bridge contacts in order to short-circuit the single module and thereby ground it.

[0023] Preferably, the grounding and protection device comprises an electric drive, which moves the switching bar from the working position to the grounding position. The electric drive further preferably moves the switching bar via a lead screw.

[0024] In a preferred embodiment, the ground terminal is formed by a ground rail, and the switching strip is configured such that, when the switching strip is moved from the working position to the ground position, a contact blade that is electrically connected to the bridge contact engages in the ground rail. In other words, the electrical connection to the ground is established by mechanical engagement between a contact blade that is electrically connected to the switching strip or is part of the switching strip and the ground rail. Thus, by a simple visual check whether the contact blade is in contact with the ground rail, it can be determined whether a single module of the modularly constructed voltage and power converter is grounded.

[0025] Preferably, when the switching bar moves from the working position to the grounding position, the contact blade is locked with the grounding rail, thereby preventing the connection between the contact blade and the grounding rail from being disconnected without external influence or operation.

[0026] The grounding and protection device preferably comprises a push rod, by means of which the switching bar can be manually moved from the operating position to the grounding position, wherein an operator of the grounding and protection device can preferably identify from the position of the push rod whether the switching bar is in the operating position or in the grounding position. Thus, an operator of the modular voltage and power converter can directly identify from the position of the push rod whether the device is in operation or has been grounded.

[0027] According to a second aspect, a modularly constructed voltage and power converter is provided, which is used to convert a primary AC voltage having one or more phases into a secondary voltage using one or more combined grounding and protection devices according to the aforementioned embodiments. The voltage and power converter comprises a plurality of single modules connected in series for each phase of the primary AC voltage, wherein each single module has a voltage input and a voltage output for receiving the phase of the primary voltage, wherein each voltage input is conductively connected to an input contact of the grounding and protection device, and each voltage output is conductively connected to an output contact of the grounding and protection device.

[0028] The advantages of the voltage and power converter correspond to the advantages of the combined grounding and protection device used therein.

[0029] Preferably, each single module comprises a transformer and a spark gap, the transformer being used for voltage and power conversion between the input side of the single module and the output side of the single module, wherein the voltage input and the voltage output of the single module are arranged on the input side of the single module, and wherein the spark gap is arranged in parallel with the transformer and configured such that a voltage flashover occurs when the voltage drop across the spark gap exceeds a third threshold value. Spark gaps within a single module can lead to controlled destruction of the single module in the event of a fault, in particular when the variable resistor and / or the spark gap of the combined grounding and protection device are insufficient.

[0030] Each single module preferably comprises a housing, which is designed so that when a single module is damaged due to overvoltage, the single modules arranged adjacent to the damaged single module are not damaged. In this way, the losses caused by the damage of individual single modules are limited in an advantageous manner, and the voltage and power converter remains in principle operationally ready.

[0031] Preferably, the variable resistor is arranged so that when a single module is damaged due to overvoltage, the variable resistor is not damaged. The variable resistor connects the input contact with the output contact, and the input contact and the output contact are respectively connected to the voltage input terminal and the voltage output terminal of the damaged single module. This can be ensured in particular in the following manner, that is, the variable resistor can bear the branch current until it decays, and at the same time use its variable resistor voltage instead of the monomer to contribute to the reverse voltage of the branch. In this way, the voltage and power converter can continue to operate because the variable resistor bridges the damaged single module and is not damaged itself.

[0032] The present invention will be described in more detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the figure:

[0034] Figure 1 shows a schematic structure of an embodiment of a modularly constructed voltage and power converter,

[0035] Figure 2 A schematic diagram showing one embodiment of a voltage and power converter with grounding and protection devices in an operating position,

[0036] Figure 3 Show Figure 2 A schematic diagram of an embodiment of the present invention is in a grounded position,

[0037] Figure 4 A perspective view showing an embodiment of a voltage and power converter including an embodiment of a grounding and protection device in a grounded position,

[0038] Figure 5 yes Figure 4 A second perspective view of an embodiment of the present invention, wherein the grounding and protection device is in the working position,

[0039] Figure 6 Shown through Figure 4 and Figure 5 A sectional view of a portion of an embodiment of the grounding and protection device in a working position,

[0040] Figure 7 Show Figures 4 to 6 Another cross-sectional view of a portion of an embodiment of the grounding and protection device in the grounded position,

[0041] Figure 8 Show Figures 4 to 7 A perspective view of a portion of an embodiment of the grounding and protection device in a working position,

[0042] Fig. 9 Show Figures 4 to 8 Another perspective view of a portion of an embodiment of the grounding and protection device in the grounding position,

[0043] Fig.10 Show Figures 4 to 10 A perspective detail view of another part of the embodiment of the invention,

[0044] Fig.11 Show Figures 4 to 10 A cross-sectional view of another portion of an embodiment of the present invention, and

[0045] Fig.12 Schematic diagram showing the structure of a single module of a modularly constructed voltage and power converter. DETAILED DESCRIPTION

[0046] Figure 1 An exemplary embodiment of a modularly constructed voltage and power converter 1 is shown, with which a three-phase high voltage is converted into a DC voltage. Figure 1 A solid-state transformer 2, also called a power electronic transformer, is shown in FIG as an example of a modularly constructed voltage and power converter 1. For example, the high voltage may be a three-phase AC voltage with a voltage of 20 kV, while the DC voltage is + / -750V.

[0047] The voltage and power converter 1 has phase conductors R, S, T for each phase of the three-phase high voltage and two output conductors 3, 4 for direct voltage. The voltage of the first output conductor 3 is, for example, -750V, while the voltage of the second output conductor 4 is correspondingly +750V.

[0048] The voltage and power converter 1 has six individual modules 5 connected in series for each phase of the primary AC voltage. Figure 1 The voltage and power converter shown in has a total of 18 individual modules. Since the individual modules 5, which can also be referred to as individual cells or single individual units, are connected in series, only a portion of the high voltage is stepped down at each individual module. Figure 1 Only a few of the individual modules 5 are provided with reference numerals, so that the figure as a whole remains readable. Each individual module 5 comprises power electronics, which convert a part of a phase of the high voltage into a DC voltage. The structure of the (same) individual modules 5 is referred to elsewhere. Fig.12 Detailed description.

[0049] exist Figure 2 and Figure 3In the invention, a voltage and power converter 1 for modular construction is disclosed (e.g. Figure 1 An embodiment of a combined grounding and protection device 6 (as shown). Figure 2 The combined grounding and protection device 6 is shown in a working position or state, and Figure 3 The grounding and protection device 6 is shown in the grounded position.

[0050] exist Figure 2 and Figure 3 , four single modules 5 in a modularly constructed voltage and power converter 1 are shown by way of example, and the single modules are used to convert the phase of the primary voltage. Each single module 5 has a voltage input terminal 7 and a voltage output terminal 8. In order to connect the single modules 5 in series, the voltage output terminals 8 of the single modules 5 to be connected in series are respectively connected to the voltage input terminals 7 of the subsequent single modules 5 to be connected in series. For this purpose, the combined grounding and protection device 6 includes a plurality of current strips 9. Each current strip 9 connects the voltage output terminal 8 of a single module 5 to the voltage input terminal 7 of the next single module 5.

[0051] Thus, the current strip 9 represents, on the one hand, an input contact 11, with which the current strip 9 is directly connected to the voltage input 7 of the individual modules 5 in a conductive manner. On the other hand, the current strip 9 also forms an output contact 12, at which the current strip 9 is directly connected to the voltage output 8 of the individual modules 5 in a conductive manner. The input and output contacts 11, 12 can, for example, be in direct physical contact with the voltage input 7 or the voltage output 8. In order not to Figure 2 and Figure 3 The illustrated contents in FIG. 1 are complicated, and only one input contact 11 and one output contact 12 are provided with reference numerals respectively.

[0052] The current strips 9 directly connected to the voltage input 7 of the single module 5 and the current strips 9 directly connected to the voltage output 8 of the same single module 5 are respectively connected via a variable resistor 10. The variable resistor 10 is configured such that when a voltage drop between an input contact 11 and an output contact 12 assigned to or directly connected to the voltage input 7 and the voltage output 8 of the same single module 5 exceeds a first limit value or threshold value, the variable resistor connects the directly consecutive current strips 9 to each other in an electrically conductive manner.

[0053] If a fault occurs in a single module 5, within the scope of which the current flow is interrupted within the single module 5 or between the current strip 9 and the single module 5, the conductor-conductor voltage of the high-voltage grid (e.g., 20 kV) drops directly at the separation point, which leads to corresponding damage. In particular, it may lead to complete damage to the single module 5, which in turn leads to damage to other single modules 5 and, as a result, to damage to the entire modular voltage and power converter 1. As a protective measure, a variable resistor 10 is provided for this situation, which limits the maximum voltage drop on the single module 5 to a first threshold value.

[0054] The distance d between the second end 13 of the current strip 9 and the first end 14 of the current strip 9 is selected such that a spark gap 15 is formed between the first end 14 and the second end 13 of the current strip 9, wherein the second end of the current strip is directly connected to the voltage input 7 of the individual module 5 and the first end of the current strip is directly connected to the voltage output 8 of the same individual module 5. When the voltage drop across the spark gap 15 exceeds a second threshold value, due to the selection of the distance d, a voltage flashes across the spark gap 15. The second threshold value is greater than the first threshold value, when the variable resistor 10 connects the input and output contacts 11, 12 of two directly consecutive current strips 9 to one another.

[0055] The spark gap 15 thus serves as an additional safety device when, in extreme fault situations, for example, in the case of a breakdown of the high-voltage insulation of a single module 5, a high voltage of, for example, 20 kV drops across only a few remaining single modules 5 and one of the varistor 10 also fails. In this case, the short-circuit current is carried by the spark gap 15 formed between the two current strips 9. This prevents further damage or limits the occurrence of damage. Figure 2 and Figure 3 In the illustration, only one of the spark gaps 15 is provided with a reference numeral in order not to clutter the illustration with reference numerals.

[0056] Finally, the combined grounding and protection device also comprises a non-conductive switching strip having a plurality of bridge contacts 16. The switching strip is Figure 2 and 3 It is not shown in the figure, but will be described in detail with reference to other embodiments in the subsequent content.

[0057] The number of bridge contacts 16 corresponds to Figure 2 and Figure 3 The number of single modules 5 for which the combined grounding and protection device 6 is provided, that is, a bridge contact 16 is provided for each single module 5 and the bridge contact is also assigned to the single module. Figure 2 and Figure 3The switching bar (not shown) can be moved back and forth between the working position and the grounding position. The bridge contact 16 is arranged on the switching bar so that the bridge contact moves back and forth between the working position and the grounding position together with the switching bar.

[0058] Here, the bridge contacts 16 are particularly arranged on the switching strip, so that when the switching strip is in the grounding position, each bridge contact 16 conductively connects the input contact 11 and the output contact 12, which are assigned to the same single module 5. In other words, the bridge contacts 16 short-circuit the input contacts 11 and the output contacts 12 respectively provided for connection to the same single module 5 in the grounding position of the switching strip. If the switching strip is in the working position, the input contacts 11 and the output contacts 12 assigned to the same single module 5 are not connected via the bridge contacts 16. Therefore, the input and output contacts 11, 12 are not short-circuited.

[0059] at last, Figure 2 and Figure 3 The combined grounding and protection device shown in FIG. 1 further has a grounding element 17, through which the short-circuited input and output contacts 11, 12 can be connected to a grounding terminal 18. Figure 2 and Figure 3 In the embodiment of FIG. 1 , the grounding element 17 and the bridge contact 16 are fixed to a switching bar (not shown) and move back and forth between the operating position and the grounding position together with the switching bar.

[0060] exist Figure 3 , the grounding and protection device 6 is shown in the grounded state, wherein the control strip (not shown) is in the grounded position. In this position, the grounding element 17 connects the current strip 9, whose first end 14 is connected to the voltage output 8 of the last single module 5 connected in series, to the grounding terminal 18. All current strips 9 are electrically conductively connected to one another or short-circuited via the bridge contact 16. Therefore, all current strips 9 and thus the single modules 5 are also connected to the grounding terminal 18 and thus to the ground 19. Therefore, the single modules 5 connected to the combined grounding and protection device 6 are current-free in the grounded state of the combined grounding and protection device.

[0061] The working state of the grounding and protection device 6 is Figure 2 In this operating state, the switching bar (not shown) is in the operating position, so that the individual current strips 9 are no longer connected via the bridge contacts 16 and no connection is established between the last current strip 9 and the grounding terminal 18 via the grounding element 17. The individual modules 5 to be protected by the grounding and protection device 6 are therefore ready for operation and can convert the applied high voltage phase into a DC voltage.

[0062] Please refer to the attached Figures 4 to 11An embodiment of a modularly constructed voltage and power converter 1 is described, which has six embodiments of a combined grounding and protection device 6. In this case, Figure 4 and Figure 5 The external perspective view of the modularly constructed voltage and power converter 1 is shown, and Figures 6 to 11 Different details of the voltage and power converter 1 or the combined grounding and protection device 6 , respectively, are shown.

[0063] exist Figure 4 and 5 The voltage and power converter 1 shown in FIG. 1 is again a solid-state transformer (SST) 2, which is configured to convert a three-phase 20 kV input AC voltage into a + / -750 V DC voltage. Figure 4 In the embodiment, the voltage and power converter 1 is grounded by means of a combined grounding and protection device 6, and Figure 5 Converter 1 in is in operation ready state.

[0064] In order to convert each phase of the input AC voltage or high voltage, the converter 1 has 28 single modules 5 connected in series. Figure 4 and 5 In order not to affect readability, only a single module is indicated by a reference numeral in each single module 5. The single modules 5 are arranged in the modular converter 1 in the form of a stack or a column 20, wherein the single modules 5 of two columns 20 are connected in series in order to convert one of the three phases of the input AC voltage into a DC current or a DC voltage.

[0065] In addition, Figure 5 It can be seen that each individual module 5 is arranged in its own housing 21. The housing 21 is made of metal, for example, and is designed in such a way that in the event of explosive destruction of components of an individual module 5 due to overpressure, adjacent individual modules 5 are not damaged or at least only slightly damaged.

[0066] For each column or stack 20 of single modules 5, the modular voltage and power converter 1 has a separate combined grounding and protection device 6. Therefore, for each phase of the high voltage, not only is there exactly one combined grounding and protection device 6, but two combined grounding and protection devices 6 are provided. Figures 6 to 11 The details of the grounding and protection devices 6 are described in more detail. However, at this point, it should be noted that each of the grounding and protection devices 6 has a push rod 22, the position of which indicates whether the corresponding grounding and protection device 6 or the single module 5 connected thereto is in operation (e.g. Figure 5 ) or grounding (such as Figure 4 ).

[0067] In order to switch between the working position and the grounding position or the corresponding state, the user can manually move the push rod 22 of the corresponding grounding and protection device 6 connected to the switching bar back and forth. Alternatively, the switching can also be carried out automatically by an electric servo drive 23 in the form of a spindle drive 23, which also moves the switching bar and thus also the push rod 22. Only a few spindle drives 23 are provided with reference numerals in order not to clutter the drawings. At the position of the push rod 22, the user or operator of the device can advantageously directly see whether the converter 1 is current-free, i.e. grounded.

[0068] Figures 6 to 9 Show Figure 4 and Figure 5 A partial embodiment of the combined grounding and protection device 6 in FIG. Figure 6 and Figure 7 A partial cross-sectional view of the grounding and protection device 6 is shown, and Figure 8 and Fig. 9 A perspective view is shown, in which some elements of the device 6 are shown transparently. Figure 6 and Figure 8 The grounding and protection device 6 is shown in the working position, while Figure 7 and Fig. 9 The grounding and protection device 6 is shown in the grounding position. For the sake of completeness, it should be noted that Figure 6-9 Slightly different details of the combined grounding and protection device 6 are shown.

[0069] This embodiment of the combined grounding and protection device 6 firstly comprises a support rail 37 on which a plurality of varistors 10 are arranged. Figure 6-9 In each of the figures, only one variable resistor 10 is shown. Overall, the combined grounding and protection device 6 comprises 14 variable resistors, each of which is used for a single module 5 to be protected by the device 6. In the illustrated section, a further variable resistor is also arranged, as can be seen on the correspondingly illustrated fixing means 24. However, the description of these variable resistors is omitted in order not to obscure the underlying design of the grounding and protection device 6.

[0070] If already referred to Figure 2 and 3 As described, the variable resistor 10 is provided for being electrically conductively connected to the voltage input 7 and the voltage output 8 of the single module 5. The variable resistor 10 is configured to electrically conductively connect the voltage input 7 to the voltage output 8 of the corresponding single module 5 when the voltage drop across the variable resistor 10 exceeds a first threshold value. Thus, the variable resistor 10 prevents the single module 5 from being damaged in the event of an overvoltage higher than the first threshold value.

[0071] The grounding and protection device 6 further comprises a plurality of current strips 9, which are respectively provided for electrically conductively connecting the voltage output terminal 8 of the preceding single module 5 in the series circuit of the single modules 5 to the voltage input terminal 7 of the following single module 5 in the series circuit of the single modules 5. The input and output contacts 11, 12 of the device 6 for establishing contact between the current strips 9 and the voltage input and output terminals 7, 8 are arranged at Figure 6-9 Not shown.

[0072] Furthermore, the grounding and protection device 6 comprises a plurality of bridge contacts 16, which are arranged on a non-conductive switching strip 25. The bridge contacts 16 are arranged on the switching strip 25 so that they move together with the switching strip 25 along an adjustment direction 26, in which the switching strip 25 is in the grounding position (in the Figure 7 and Fig. 9 ) and the working position (shown in Figure 6 and Figure 8 ).

[0073] If the switching strip 25 is in the operating position, each bridge contact 16 is connected to only one of the current strips 9 via two spring-prestressed contact bolts 27, 28. In the operating position, the bridge contacts 16 thus form a parallel current path to the current strips 9 and thus contribute to the series connection of the individual modules 5.

[0074] On the contrary, if the switching bar 25 is arranged in the ground position, as it is in Figure 7 and Fig. 9 As shown in , each of the bridge contacts 16 connects the spring-preloaded contact bolt 27 of the preceding current strip 9 in the series circuit of the single module 5 with the spring-preloaded contact bolt 28 of the following current strip 9 in the series circuit of the single module 9. As a result, the current strips 9 and thus the single modules are short-circuited, their voltage inputs or voltage outputs are respectively connected to two current strips 9 that are conductively connected via the bridge contacts 16, and the single modules 5 are de-energized when the bridge contacts 16 are simultaneously connected to ground.

[0075] Finally, a spark gap 15 is formed between the first and second ends 13, 14 of the current strip 9, which is designed such that the voltage flashes from the second end 14 of the current strip 9 preceding in the series circuit to the first end 13 of the current strip 9 following in the series circuit, when the voltage between the ends 13, 14 exceeds a second threshold value which is greater than the first threshold value. The second threshold value can be set by the distance d between the first end 13 and the second end 14. The spark gap 15 is thus arranged parallel to the varistor 10 and protects the individual modules 5 from overvoltage if the varistor 10 fails.

[0076] exist Fig.102 further shows the structure of the push rod assembly 29, by which the switch bar 25 can be moved back and forth between the working position and the grounding position. The switch bar 25 is usually moved by a servo motor 23, which is powered by an external power supply (not shown). The servo motor 23 has a non-self-locking screw and has a brake. If the motor stops running, the switch bar 25 can be moved manually by means of the push rod 22.

[0077] Furthermore, by moving the switching strip 25, the contact blade 30 is moved, which connects the current strip 9 to the ground terminal 18. The contact blade 30 is locked with the ground terminal 18, so that an additional force is required to disengage the contact blade 30 from the ground terminal 18 again.

[0078] Fig.11 Another detail of the structure of the push rod assembly 29 is shown. In particular, a screw 31 is shown, which connects the contact blade 30, the (extended) current strip 9, the switching strip 25 and the adjustment element 32. The servomotor 23 can change the position of the switching strip 25 via the adjustment element 32. The contact blade 30 and the extended current strip 9 are electrically conductively connected to each other, while the disc spring 33 prevents an electrically conductive connection between the contact blade 30 and the adjustment element 32. The screw 31 is also designed to be non-conductive.

[0079] Finally, in Fig.12 An equivalent circuit diagram for a single module 5 is shown in FIG. The single module 5 comprises a voltage input 7 and a voltage output 8, through which the high voltage to be converted is carried. In addition, the single module 5 has two DC voltage outputs 34. The central element of the single module is a small transformer 35, which can advantageously be a medium-frequency transformer with a frequency of 10 kHz to 100 kHz, because this enables a small design in a simple manner. If the transformer 35 fails due to overvoltage, another spark gap 36 is additionally provided. The spark gap 36 in the interior of the single module 5 is designed so that a voltage flashover occurs when a third threshold value is exceeded, wherein the third threshold value is greater than the second threshold value. The spark gap 36 prevents or limits damage to the single module 5 in extreme fault conditions that essentially result in a total high voltage drop on the single module 5.

[0080] Reference numerals list

[0081] 1 Modular Voltage and Power Converters

[0082] 2 Solid-state transformers, power electronic transformers

[0083] R, S, T phase conductors

[0084] 3, 4 DC output conductor

[0085] 5 Single module, single monomer, monomer

[0086] 6 Combined grounding and protection device

[0087] 7 Voltage input terminal

[0088] 8 Voltage output terminal

[0089] 9 Current belt

[0090] 10. Variable resistor

[0091] 11 Input contacts

[0092] 12 output contacts

[0093] 13 Second end of current strip 9

[0094] 14 First end of current strip 9

[0095] 15 At the second end of one current strip 9 and at the first end of the next current strip 9

[0096] Distance between ends

[0097] 16 bridge contacts

[0098] 17 Grounding element

[0099] 18 Ground terminal

[0100] 19 Land

[0101] 20 columns or stacks of single modules

[0102] 21 Single module housing

[0103] 22 Putter

[0104] 23 Servo drive, spindle motor

[0105] 24 Fixing mechanism

[0106] 25 Switch Bar

[0107] 26 Adjustment direction

[0108] 27 Contact bolt

[0109] 28 Contact bolt

[0110] 29 Push rod assembly

[0111] 30 Contact knife

[0112] 31 Bolt

[0113] 32 Adjustment elements

[0114] 33 disc spring

[0115] 34 DC output terminal

[0116] 35 Transformer

[0117] 36 Spark Gap

[0118] 37 Bracket rail

Claims

1. A combined grounding and protection device (6) for a modularly constructed voltage and power converter (1) for converting a primary alternating voltage having one or more phases into a secondary voltage, in, The voltage and power converter (1) comprises, for each phase of the primary alternating voltage, a plurality of single modules (5) to be connected in series, wherein each single module (5) has a voltage input terminal (7) and a voltage output terminal (8) for receiving the phase of the primary voltage, The combined grounding and protection device (6) comprises a plurality of input contacts (11) and a plurality of output contacts (12), wherein the input contacts and the output contacts are configured such that each input contact (11) can be conductively connected to a voltage input terminal (7) of a single module (5) of the voltage and power converter (1), and each output contact (12) can be conductively connected to a voltage output terminal (8) of a single module (5) of the voltage and power converter (1), and each input contact (11) and output contact (12) connected to the voltage input terminal (7) and the voltage output terminal (8) of the same single module (5) are connected by means of a variable resistor (10), wherein the variable resistor (10) is configured such that when a voltage dropped on the variable resistor (10) exceeds a first threshold value, the input contact (11) is conductively connected to the output contact (12), and The combined grounding and protection device (6) further comprises a non-conductive switching bar (25) having a plurality of bridge contacts (16), wherein the switching bar (25) is configured to move from a working position to a grounding position, wherein when the switching bar (25) is in the grounding position, each of the plurality of bridge contacts (16) electrically connects the input contact (11) to the output contact (12), and the input contact and the output contact can be electrically connected to the voltage input terminal (7) and the voltage input terminal (12) of the same single module (5). The switching bar (25) is connected to the voltage input terminal (7) and the voltage output terminal (8) of the same single module (5), and the input contact (11) and the output contact (12) which are conductively connected through the bridge contact (16) are connected to the ground terminal (18), and when the switching bar (25) is in the working position, the input contact (11) and the output contact (12) which can be connected to the voltage input terminal (7) and the voltage output terminal (8) of the same single module (5) are not conductively connected through the bridge contact (16), and the input contact (11) and the output contact (12) are also not connected to the ground terminal (18).

2. The grounding and protection device (6) according to claim 1, wherein: In order to connect the single modules (5) of the voltage and power converter (1) in series, an output contact (12) that can be connected to the voltage output terminal (8) of the single module (5) to be connected in series first is conductively connected to an input contact (11) by means of a current belt (9), and the current belt can be connected to the voltage input terminal (7) of the single module (5) to be connected in series later.

3. The grounding and protection device (6) according to claim 1 or 2, wherein: A spark gap (15) is constructed between an input contact (11) and an output contact (12) respectively connectable to a voltage input terminal (7) and a voltage output terminal (8) of the same single module (5), and the spark gap is configured so that a voltage flashover occurs when a voltage drop across the spark gap (15) exceeds a second threshold value, wherein the second threshold value is preferably greater than the first threshold value.

4. The grounding and protection device (6) according to claims 2 and 3, wherein: The spark gap (15) is respectively formed between a second end (13) of the current strip (9) connected to the input contact (11) and a first end (14) of the current strip (9) connected to the output contact (12).

5. The grounding and protection device (6) according to any one of the preceding claims, wherein: For connecting the current strip (9) to the bridge contact (16), spring-mounted contact bolts (27, 28) are provided, which are preferably fastened in a common holder made of a non-conductive material.

6. The grounding and protection device (6) according to claim 5, wherein: Each current strip (9) comprises two contact bolts (27, 28) which respectively contact the same bridge contact (16) in the operating position of the switching strip (25) and respectively contact different bridge contacts (16) in the grounding position of the switching strip (25).

7. The grounding and protection device (6) according to any one of the preceding claims, wherein: The grounding and protection device (6) comprises an electric drive (23) which moves the switching bar (25) from the working position to the grounding position, wherein the electric drive (23) preferably moves the switching bar (25) via a lead screw.

8. The grounding and protection device (6) according to any one of the preceding claims, wherein: The grounding terminal (18) is formed by a grounding track, and the switching bar (25) is configured so that when the switching bar (25) moves from the working position to the grounding position, a contact blade (30) conductively connected to the bridge contact (16) is embedded in the grounding track (18).

9. The grounding and protection device (6) according to claim 8, wherein: When the switching bar (25) moves from the working position to the grounding position, the contact blade (30) is locked with the grounding track (18).

10. The grounding and protection device (6) according to claim 9, wherein: The grounding and protection device (6) comprises a push rod (22), by means of which the switching bar (25) can be manually moved from a working position to a grounding position, wherein an operator of the grounding and protection device (6) can preferably identify from the position of the push rod (22) whether the switching bar (25) is in the working position or in the grounding position.

11. A modularly constructed voltage and power converter (1) for converting a primary alternating voltage having one or more phases into a secondary voltage using one or more combined grounding and protection devices (6) according to any one of claims 1 to 10, in, The voltage and power converter (1) comprises a plurality of single modules (5) connected in series for each phase of the primary AC voltage, wherein each single module (5) has a voltage input terminal (7) and a voltage output terminal (8) for receiving the phase of the primary voltage, wherein each voltage input terminal (7) is electrically conductively connected to an input contact (11) of the grounding and protection device (6), and each voltage output terminal (8) is electrically conductively connected to an output contact (12) of the grounding and protection device (6).

12. The voltage and power converter (1) according to claim 11, wherein: Each single module (5) comprises a transformer (35) and a spark gap (36), wherein the transformer is used for performing voltage and power conversion between an input side of the single module (5) and an output side of the single module (5), The voltage input terminal (7) and the voltage output terminal (8) of the single module (5) are arranged on the input side of the single module (5), and The spark gap (36) is arranged in parallel with the transformer (35) and is configured such that a voltage flashover occurs when a voltage drop across the spark gap (36) exceeds a third threshold value.

13. A voltage and power converter (1) according to claim 11 or 12, wherein: Each individual module (5) comprises a housing (21) which is designed such that, when an individual module (5) is damaged due to overpressure, individual modules (5) arranged adjacent to the damaged individual module (5) are not damaged.

14. A voltage and power converter (1) according to claim 11, 12 or 13, wherein: The variable resistor (10) is arranged so that when a single module (5) is damaged due to overvoltage, the variable resistor (10) is not damaged, the variable resistor connects the input contact (11) with the output contact (12), and the input contact and the output contact are respectively connected to the voltage input terminal (7) and the voltage output terminal (8) of the damaged single module (5).

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