Current equalization monitoring system of direct current controllable energy dissipation device and voltage limiter column matching method thereof

Abstract

The application discloses a current sharing monitoring system of a direct-current controllable energy dissipation device and a voltage limiter column grouping method thereof, wherein the grouping method considers the number of voltage limiter columns of the direct-current controllable energy dissipation device, the current flowing through the voltage limiter when the protected equipment is overvoltage, and a current distribution coefficient, a single valve piece breakdown short circuit scenario of a voltage limiter column is simulated by using an electromagnetic transient simulation model, the voltage limiter column is grouped according to the current distribution under the scenario and the current distribution coefficient setting value, or the final grouping scheme is obtained by continuing to adjust and check through iteration, and then a current measuring device is configured for each group of voltage limiter columns according to the grouping scheme, so that current sharing monitoring calculation and logical judgment are realized. The application can reduce the cost of the current sharing monitoring system of the direct-current controllable energy dissipation device, and can reliably output an alarm signal when the current distribution coefficient is abnormal.

Description

Technical Field

[0001] This invention relates to the field of high voltage direct current transmission technology, and in particular to a current sharing monitoring system for a controllable DC energy dissipation device and a method for matching voltage limiter columns. Background Technology

[0002] Hybrid DC transmission technology combines the advantages of traditional DC transmission (LCC) and flexible DC transmission (VSC), effectively expanding the applicability of DC transmission systems and representing one of the future development directions for large-scale, long-distance, and high-capacity power transmission. However, various fault conditions may occur during the operation of a hybrid DC system, such as: 1) LCC converter commutation failure, resulting in power not being fed into the AC grid; 2) a near-field short circuit in the receiving-end grid connected to the VSC converter, causing power transmission obstruction; and 3) emergency blocking of the VSC converter due to internal faults. In these situations, the sending-end converter station typically cannot complete a rapid power reduction within milliseconds, resulting in a power surplus in the system. If this surplus power is not discharged and absorbed, it will continuously charge the capacitors in the VSC valve group, leading to overvoltage bypass blocking of the VSC submodule and affecting normal system operation. Therefore, to prevent overvoltage of the VSC submodule from causing complete blocking of the VSC converter, a controllable energy dissipation device based on zinc oxide valve plates is configured at both ends of the VSC to discharge the system's transient surplus power.

[0003] Patent 201921646322.8 discloses an energy dissipation device and a high-voltage power transmission system, such as... Figure 1 As shown, it includes: a fixed energy dissipation element 101, a controlled energy dissipation element 103, and a control module 102. A first fast switching unit and a first mechanical circuit breaker are connected in parallel between the first and second terminals of the control module 102. The first mechanical circuit breaker is used for commutation and interrupts the DC current when the protection module is deactivated.

[0004] To enable the energy dissipation device (hereinafter referred to as the controllable energy dissipation device) to absorb more energy, zinc oxide valve plates need to be connected in series to form a voltage limiter column, which is then installed inside a composite jacket. Multiple voltage limiter columns are then connected in parallel, including fixed elements 101 and controlled elements 103. Generally, hundreds of voltage limiter columns are needed, with multiple columns connected in parallel to increase energy absorption. During the operation of the controllable energy dissipation device, if an overvoltage occurs at the protected equipment terminals, after the control switch is closed, there is a possibility that one or more zinc oxide valve plates in the controlled element may break down and short-circuit. To monitor the fault condition of a single zinc oxide valve plate breaking down and short-circuiting, current sharing monitoring of the voltage limiter columns is required. Installing a current measuring device on each voltage limiter column would be very costly and require a large amount of computation. Summary of the Invention

[0005] The purpose of this invention is to provide a current sharing monitoring system for a DC controllable energy dissipation device and a method for grouping its voltage limiter columns. Considering the number of voltage limiter columns in the DC controllable energy dissipation device, the current flowing through the voltage limiter when the protected equipment is overvoltageed, and the current distribution coefficient, the voltage limiter columns are grouped, and a current measuring device is configured for each group of zinc oxide voltage limiters. This enables current sharing monitoring calculations and logical judgments, allowing for reliable output of alarm signals when the current distribution coefficient is abnormal, while simultaneously reducing the cost of the current sharing monitoring scheme for the DC controllable energy dissipation device. The technical solution adopted by this invention is as follows.

[0006] On one hand, the present invention provides a current sharing monitoring system for a DC controllable energy dissipation device, wherein the DC controllable energy dissipation device includes multiple parallel voltage limiter columns, and each voltage limiter column includes multiple valve plates connected in series.

[0007] The multiple parallel pressure limiting columns are divided into multiple pressure limiting column groups, and each pressure limiting column group is respectively equipped with a current sensor. The output terminals of all current sensors are respectively connected to a current sharing monitoring device.

[0008] The current sensor is used to collect the current flowing through the corresponding voltage limiter column group;

[0009] The current sharing monitoring device is used to calculate the current distribution coefficient based on the current received from each group of voltage limiter columns, compare it with the current distribution coefficient setting value, and output an alarm signal based on the comparison result.

[0010] By grouping the voltage limiter columns and setting current sensors in each group, the current distribution coefficient can be calculated uniformly by the current sharing monitoring device, which can greatly reduce the cost of the current sharing monitoring scheme for DC controllable energy dissipation devices and the amount of data that the system needs to transmit and process.

[0011] Optionally, in this invention, the current sensor is an optical current transformer, and is preferably installed at the high-voltage end of the corresponding voltage limiter column group.

[0012] Optionally, the rated voltage value U of the current sensor e The voltage reference value U is selected according to the following formula. e The value obtained after rounding up:

[0013]

[0014] In the formula, n set I represents the number of parallel columns within a single pressure relief column group. total This represents the total current flowing through the voltage limiter under overvoltage conditions of the protected equipment, where p represents the total number of parallel voltage limiter columns in the DC controllable energy dissipation device. The accuracy of the current sensor at rated current is preferably not less than 0.2%.

[0015] In a second aspect, the present invention provides a method for assembling pressure limiter columns in the current sharing monitoring system described in the first aspect, comprising:

[0016] Acquire the voltage limiter configuration data of the DC controllable energy dissipation device. The voltage limiter configuration data includes the total number of parallel voltage limiter columns, the number of series valves in each voltage limiter column, and the total current flowing through the voltage limiter under overvoltage conditions of the protected equipment.

[0017] An electromagnetic transient simulation model of a DC controllable energy dissipation device is built based on the voltage limiter configuration data.

[0018] The electromagnetic transient simulation model was used to simulate the breakdown and short circuit of a single valve plate in a single voltage limiter column, and the current of each voltage limiter column was obtained.

[0019] Calculate the ratio between the current in the short-circuit voltage limiter column and the current in other voltage limiter columns;

[0020] Based on the aforementioned multiple relationship and the preset current distribution coefficient setting value, determine the number of voltage limiter columns in each group of voltage limiter columns in the DC controllable energy dissipation device, as well as the number of voltage limiter column groups.

[0021] The pressure limiter grouping scheme obtained through the above technical solutions can output corresponding alarm signals by the current sharing monitoring device through logic calculation when the protected equipment is over-voltage or the pressure limiter breaks down, ensuring timely handling of fault conditions such as zinc oxide valve plate breakdown and short circuit, and reducing the impact of the fault.

[0022] Optionally, to further ensure that the current sharing monitoring device can reliably output alarms under fault conditions of zinc oxide valve plate breakdown and short circuit, the present invention also verifies and corrects the grouping scheme obtained by the aforementioned grouping method, that is, the method further includes:

[0023] S1. Based on the currently determined number of pressure limiter column groups and the number of pressure limiter columns in each group, group the pressure limiter columns in the electromagnetic transient simulation model.

[0024] S2, for at least one of the voltage limiter column groups, simulate the breakdown and short circuit of a single valve plate in a single voltage limiter column under overvoltage conditions of the protected equipment, and obtain the current of each voltage limiter column in the current voltage limiter column group;

[0025] S3, Calculate the current distribution coefficient of the voltage limiter column group based on the current of each voltage limiter column in the current voltage limiter column group and the average current of a single column of all voltage limiter columns.

[0026] S4, determine whether the calculated current distribution coefficient meets the preset alarm range and whether the duration meets the preset duration threshold:

[0027] If all conditions are met, the number of pressure limiter columns and the number of pressure limiter column groups in each current pressure limiter column group will be determined as the optional pressure limiter column grouping scheme.

[0028] If any condition is not met, the number of voltage limiter columns in each group of voltage limiter columns is reduced by 1, and the number of voltage limiter column groups is calculated accordingly. After updating the voltage limiter column grouping scheme, the process returns to steps S1-S4 until the calculated current distribution coefficient meets the preset alarm range and the duration meets the preset duration threshold, thus obtaining the optional voltage limiter column grouping scheme.

[0029] In step S3 above, the current distribution coefficient of the voltage limiter column group is calculated based on the current of each voltage limiter column in the current voltage limiter column group and the average current of a single column of all voltage limiter columns. The formula is as follows:

[0030]

[0031] In the formula, k = 1, 2, 3, ... are the group numbers of the pressure relief column group, ξ k i represents the current distribution coefficient of the voltage limiter column group when a single valve plate in a single voltage limiter column breaks down and short-circuits the voltage limiter column it belongs to, for the k-th voltage limiter column group. MOV_k i represents the current flowing through the k-th voltage limiter column group. AVE_S This represents the average current of a single voltage limiter in all voltage limiter columns, and has... n is the average current of a single-column voltage limiter. k This represents the number of parallel pressure limiter columns within the k-th pressure limiter column group.

[0032] To further ensure the reliability of the final grouping scheme, as one implementation method, when verifying and correcting the above grouping scheme, for each group of pressure limiter columns in the pressure limiter column grouping scheme, the overvoltage condition of the protected equipment can be simulated by simulating the breakdown and short circuit of a single valve plate in a single pressure limiter column, and the corresponding current distribution coefficient can be obtained:

[0033] If the current distribution coefficient obtained by simulation for each voltage limiter column group meets the preset alarm range and the duration meets the preset duration threshold, then the current voltage limiter column grouping scheme is determined as the final voltage limiter column grouping scheme.

[0034] In formulating and verifying the grouping scheme, the method of this invention utilizes an electromagnetic transient simulation model to simulate the scenario of a single valve plate short-circuiting in the voltage limiter column. Specifically, it is assumed that in the voltage limiter configuration data, the total number of parallel voltage limiter columns is p, the number of series valve plates in each voltage limiter column is s, and the total current flowing through the voltage limiter under overvoltage conditions of the protected equipment is I. total ;

[0035] The electromagnetic transient simulation model of the DC controllable energy dissipation device built based on the voltage limiter configuration data includes:

[0036] In the electromagnetic simulation transient model of the pressure limiter, the volt-ampere characteristic of one of the pressure limiter columns is set as (s-1) series valve plates, and the remaining (p-1) pressure limiter columns are set as s series valve plates.

[0037] During the verification and correction of the grouping scheme, in step S2, for the k-th voltage limiter column group, when simulating the breakdown and short circuit of a single valve plate in a single voltage limiter column under overvoltage conditions of the protected equipment, the electromagnetic transient simulation model of the DC controllable energy dissipation device is configured as follows:

[0038] The volt-ampere characteristic of one of the pressure relief columns in the k-th pressure relief column group is set with (s-1) series valve plates, and the remaining pressure relief columns are set with s series valve plates.

[0039] After the electromagnetic transient simulation model is built, the total current I flowing through the voltage limiter when the protected equipment is overvoltage is determined. total The current flows through all the voltage limiter columns. Simulate the voltage limiter column containing (s-1) series valves where a single valve breaks down and short-circuits the voltage limiter column, and obtain the current of each voltage limiter column at this time.

[0040] Based on the simulation results of the current in each voltage limiter column, it can be calculated that the current in the short-circuit voltage limiter column is x times the current in the other voltage limiter columns. Therefore, the maximum reference value n′ for the number of columns in a single voltage limiter group can be calculated using the following formula:

[0041] n′<(x-1) / (ξ set -1)

[0042] In the formula, ξ set This indicates the preset current distribution coefficient setting value, which is generally set to 1.06 to 1.1 and can be adjusted as needed.

[0043] The number of parallel columns n in each group of pressure-limiting columns is determined based on the maximum column count reference value n′. set ;

[0044] Based on the number of parallel columns n of each group of pressure relief columns. set The total number of parallel pressure relief column columns determines the number of pressure relief column groups.

[0045] Optionally, the number of parallel columns n for each group of pressure relief columns is determined based on the maximum column reference value n′. set ,include:

[0046] The maximum column count reference value n′ is rounded down to obtain an integer n;

[0047] Determine the number n of parallel columns in each group of pressure relief columns. setFor: n set =nn m , where n m This indicates the preset column margin. By rounding and taking the column margin into account, the reliability of the final grouping scheme can be further improved, ensuring that the current sharing monitoring function can reliably alarm when the equipment is overpressured.

[0048] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the pressure limiter column grouping method as described in the first aspect.

[0049] Beneficial effects

[0050] Compared with the prior art, the present invention has the following advantages and advancements:

[0051] (1) The present invention achieves the current sharing monitoring function by grouping the parallel voltage limiter columns and monitoring the current of each group and then calculating the current distribution coefficient. This can greatly reduce the current measurement device required for the current sharing monitoring system and reduce the system cost. Combined with the voltage limiter grouping method of the present invention, the reliability of the current sharing monitoring function can be guaranteed.

[0052] (2) When designing the grouping scheme, the pressure limiter grouping method of the present invention considers the total number of columns of the pressure limiter, the number of valves of each pressure limiter, the total current flowing through the pressure limiter when the equipment is over-pressured, and the current distribution coefficient setting value. The electromagnetic transient model simulates the scenario where a single valve breaks down and short-circuits the pressure limiter column under the corresponding conditions. Based on the current distribution characteristics of each pressure limiter column and the current distribution coefficient setting value under the scenario, the grouping scheme is analyzed, which enables the grouping scheme to realize the current sharing monitoring function during actual operation.

[0053] (3) After initially determining the grouping scheme, the present invention also verifies and adjusts the grouping scheme through an electromagnetic transient simulation model. Through iterative adjustment, the final determined grouping scheme enables the current sharing monitoring function to reliably alarm when the current distribution coefficient is abnormal. Attached Figure Description

[0054] Figure 1 The diagram shown is a schematic of the energy dissipation device in the prior art;

[0055] Figure 2 The diagram shows the architecture for the current sharing monitoring function of the energy dissipation device. In the diagram, 201 is the protected device, 202 is the voltage limiter column of the fixed component, 203 is the voltage limiter column of the controlled component, 204 is the control module, 205 is the current sharing monitoring device, and 206 is the current measuring device.

[0056] Figure 3 The diagram shown is a schematic flowchart of the pressure limiter column assembly method in one embodiment of the present invention. Detailed Implementation

[0057] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details.

[0058] refer to Figure 2 The illustrated architecture for current sharing monitoring of a leakage device includes a protected device 201, a voltage limiter column 202 for fixed components, a voltage limiter column 203 for controlled components, a control module 204, a current sharing monitoring device 205, and a current measuring device 206. In existing current sharing monitoring schemes, a current measuring device 206 is installed for each voltage limiter column 203, requiring the installation of a large number of current measuring devices 206, resulting in high implementation costs for the current sharing monitoring system.

[0059] The technical concept of this invention is as follows: by grouping and installing the voltage limiter columns, and configuring a current measuring device for each group of voltage limiter columns, the measured current is transmitted to the current sharing monitoring device, realizing current sharing monitoring calculation and logical judgment, reducing the number of current measuring devices installed, and lowering the cost of the current sharing monitoring scheme. Furthermore, to ensure that the grouping scheme of the voltage limiter columns can reliably achieve the current sharing monitoring function, electromagnetic transient simulation is performed considering the actual installation scenario of the voltage limiters, thereby obtaining a reliable grouping scheme.

[0060] Example 1

[0061] This embodiment introduces a current sharing monitoring system for a DC controllable energy dissipation device, wherein the DC controllable energy dissipation device includes multiple parallel voltage limiter columns, and each voltage limiter column includes multiple valve plates connected in series.

[0062] The multiple parallel pressure limiting columns are divided into multiple pressure limiting column groups, and each pressure limiting column group is respectively equipped with a current sensor. The output terminals of all current sensors are respectively connected to a current sharing monitoring device.

[0063] The current sensor is used to collect the current flowing through the corresponding voltage limiter column group;

[0064] The current sharing monitoring device is used to calculate the current distribution coefficient based on the current received from each group of voltage limiter columns, compare it with the current distribution coefficient setting value, and output an alarm signal based on the comparison result. For example, if the actual current distribution coefficient is greater than or equal to the current distribution coefficient setting value, and the duration exceeds the set time threshold, the current sharing monitoring device outputs an alarm.

[0065] In this embodiment, the current sensor can be an optical current transformer, and the current signal is transmitted between it and the current sharing monitoring device via optical fiber. The current sensor is preferably installed at the high-voltage end of the corresponding voltage limiter column group.

[0066] The selection method for the current sensor is based on the number of parallel columns n in a single voltage limiter column group.set The total current I flowing through the voltage limiter when the equipment is overvoltage total And the total number p of the parallel voltage limiter columns, calculate the reference rated voltage of the current sensor required to be installed in each voltage limiter column group:

[0067]

[0068] For voltage reference value U e Round up to the nearest integer and use the resulting value as the rated voltage U of the current sensor. e Furthermore, the accuracy of the current sensor under rated current is not less than 0.2 class.

[0069] This embodiment reduces the cost of the current sharing monitoring scheme for DC controllable energy dissipation devices and the amount of data that the system needs to transmit and process by grouping the voltage limiter columns and setting current sensors in each group, and then having the current sharing monitoring device uniformly calculate the current distribution coefficient.

[0070] Example 2

[0071] This embodiment describes a pressure limiter column grouping method based on the flow sharing monitoring system described in Embodiment 1, with reference to... Figure 3 As shown, it specifically involves the following content.

[0072] 1. Obtain the voltage limiter configuration data of the DC controllable energy dissipation device. The voltage limiter configuration data includes the total number of parallel voltage limiter columns p, the number of series valve plates s of each voltage limiter column, and the total current I flowing through the voltage limiter under overvoltage conditions of the protected equipment. total .

[0073] 2. Based on the voltage limiter configuration data, build an electromagnetic transient simulation model of the DC controllable energy dissipation device. Specifically, set the volt-ampere characteristic of one voltage limiter column in the electromagnetic simulation transient model of the voltage limiter according to (s-1) series valve plates, and set the remaining (p-1) voltage limiter columns according to s series valve plates.

[0074] III. Using the constructed electromagnetic transient simulation model, the breakdown and short-circuiting of a single valve plate in a single voltage limiter column is simulated to obtain the current in each voltage limiter column. Specifically:

[0075] The total current I flowing through the voltage limiter when the protected equipment is overvoltage total The current flows through all the voltage limiter columns. Simulate the voltage limiter column containing (s-1) series valves where a single valve breaks down and short-circuits the voltage limiter column, and obtain the current of each voltage limiter column at this time.

[0076] 4. Calculate the multiple relationship between the current of the pressure limiter column that experiences a single valve plate breakdown and short circuit and the current of other pressure limiter columns. Specifically, based on the simulation results of the current of each pressure limiter column, it can be calculated that the current of the short-circuited pressure limiter column is x times the current of other pressure limiter columns.

[0077] 5. Based on the aforementioned multiple relationship and the preset current distribution coefficient setting value, determine the number of voltage limiter columns in each group of voltage limiter columns in the DC controllable energy dissipation device, as well as the number of voltage limiter column groups.

[0078] In this embodiment, the maximum reference value n′ of the number of columns in a single pressure relief unit is first calculated according to the following formula:

[0079] n′<(x-1) / (ξ set -1)

[0080] In the formula, ξ set This indicates the preset current distribution coefficient setting value, which is generally set to 1.06 to 1.1 and can be adjusted as needed.

[0081] Then, based on the maximum column count reference value n′, determine the number of parallel columns n for each group of pressure relief columns. set ,include:

[0082] The maximum column count reference value n′ is rounded down to obtain an integer n;

[0083] Determine the number n of parallel columns in each group of pressure relief columns. set For: n set =nn m , where n m This indicates the preset column margin.

[0084] VI. Based on the number of parallel columns n of each group of pressure relief columns. set The total number of parallel pressure-limiting column groups is used to determine the number of pressure-limiting column sets. If the total number of columns is equal to the number of parallel columns (n), then... set If the value is an integer multiple of n, it can be distributed equally; otherwise, it should be distributed according to the maximum number of parallel columns in each pressure limiter column group. set And the total number of groups should be minimized when allocating them.

[0085] Thus, the grouping scheme of the parallel pressure relief column is obtained. This scheme can be directly used to group the pressure relief columns and build a flow equalization monitoring system. In this embodiment, in order to ensure that the flow equalization monitoring device can reliably output alarms under the fault condition of zinc oxide valve plate breakdown and short circuit, the grouping scheme obtained through the above steps is used as the preliminary grouping scheme. The preliminary grouping scheme is iteratively checked and corrected through the following implementation method to obtain the final grouping scheme.

[0086] VII. Verify and revise the combination schemes obtained by the aforementioned combination methods, including the following:

[0087] S1. Based on the currently determined number of pressure limiter column groups and the number of pressure limiter columns in each group, group the pressure limiter columns in the electromagnetic transient simulation model.

[0088] S2, for at least one of the voltage limiter column groups, simulate the breakdown and short circuit of a single valve plate in a single voltage limiter column under overvoltage conditions of the protected equipment, and obtain the current of each voltage limiter column in the current voltage limiter column group;

[0089] For example, for the kth voltage limiter column group, when simulating the breakdown and short circuit of a single valve in a single voltage limiter column under overvoltage conditions of the protected equipment, the electromagnetic transient simulation model of the DC controllable energy dissipation device is configured as follows: the volt-ampere characteristic of one of the voltage limiter columns in the kth voltage limiter column group is set according to (s-1) series valves, and the remaining voltage limiter columns are set according to s series valves.

[0090] S3, based on the current of each voltage limiter column in the current voltage limiter column group and the average current of a single column of all voltage limiter columns, calculate the current distribution coefficient of the voltage limiter column group, using the following formula:

[0091]

[0092] In the formula, k = 1, 2, 3, ... are the group numbers of the pressure relief column group, ξ k i represents the current distribution coefficient of the voltage limiter column group when a single valve plate in a single voltage limiter column breaks down and short-circuits the voltage limiter column it belongs to, for the k-th voltage limiter column group. MOV_k i represents the current flowing through the k-th voltage limiter column group. AVE_S This represents the average current of a single voltage limiter in all voltage limiter columns, and has... n is the average current of a single-column voltage limiter. k This represents the number of parallel pressure limiter columns within the k-th pressure limiter column group.

[0093] S4, determine whether the calculated current distribution coefficient meets the preset alarm range and whether the duration meets the preset duration threshold t. set :

[0094] If all conditions are met, the number of pressure limiter columns and the number of pressure limiter column groups in each current pressure limiter column group will be determined as the optional pressure limiter column grouping scheme.

[0095] If any condition is not met, the number of voltage limiter columns in each group of voltage limiter columns is reduced by 1, and the number of voltage limiter column groups is calculated accordingly. After updating the voltage limiter column grouping scheme, the process returns to steps S1-S4 until the calculated current distribution coefficient meets the preset alarm range and the duration meets the preset duration threshold, thus obtaining the optional voltage limiter column grouping scheme.

[0096] When verifying and correcting the above grouping scheme, for each group of pressure limiter columns in the scheme, the current distribution coefficient can be obtained by simulating the breakdown and short circuit of a single valve plate in a single pressure limiter column under overvoltage conditions of the protected equipment.

[0097] If the current distribution coefficient obtained by simulation for each voltage limiter column group meets the preset alarm range and the duration meets the preset duration threshold, then the current voltage limiter column grouping scheme is determined as the final voltage limiter column grouping scheme.

[0098] The above current distribution coefficients all meet the preset alarm range and can be set to ξ accordingly. k >ξ set .

[0099] The following describes the implementation of the pressure limiter column grouping method of the present invention using a specific pressure limiter current equalization monitoring scenario.

[0100] Given that the number of series valves in the zinc oxide voltage limiter of the DC controllable energy dissipation device is 88 and the number of parallel columns is 136, and the total current flowing through the voltage limiter under overvoltage conditions of the protected equipment is 5000Ap, the steps for matching the voltage limiter columns are as follows:

[0101] (a) An electromagnetic transient simulation model of the current sharing monitoring system of the voltage limiter group was built. One voltage limiter column was set with 87 valves connected in series to set the volt-ampere characteristic, and the remaining 135 voltage limiter columns were set with 88 valves connected in series to set the volt-ampere characteristic. A 5000A current was simulated to flow through all voltage limiters. The simulation and calculation showed that the current of a single valve in the voltage limiter column with 87 valves connected in series was 1.7 times that of the current of other normal columns.

[0102] (b) If the current distribution coefficient setting value ξ for current sharing monitoring is... set Set to 1.06, duration threshold t set Set to 5ms, based on n′<(x-1) / (ξ) set -1) It can be seen that the maximum number of columns in a single pressure relief column group is n′ < 11.67. After rounding and considering a margin of 1 column, the number of columns in the pressure relief column group is chosen to be n. set =10 columns, then the preliminary grouping scheme of the DC controllable energy dissipation device voltage limiter is as follows: it is divided into 14 groups in total, of which 2 groups of voltage limiters each contain 8 columns of voltage limiters, and the remaining 12 groups of voltage limiters each contain 10 columns of voltage limiters.

[0103] (c) Based on the initial grouping scheme of the pressure limiter, repeat the above steps (a) and (b) to check whether the current sharing monitoring alarm function can operate reliably when a single valve plate breaks down and short-circuits. If it cannot operate reliably, reduce the number of columns in the pressure limiter group by one and re-check until the current sharing monitoring alarm function can operate reliably.

[0104] Current transformer rated current according to Rounding down the selection and using 50A increments, the rated voltage of the optical current transformer is chosen to be 400Adc. Therefore, a total of 14 optical current transformers are required for this application scenario, with an accuracy of no less than 0.2 class at rated current. The optical current transformers transmit 14 current sampling values ​​to the current sharing monitoring device via optical fiber. The current sharing monitoring device then calculates and performs logical judgments on the current distribution coefficients of the 14 voltage limiters.

[0105] Example 3

[0106] This embodiment describes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the pressure limiter column grouping method as described in Embodiment 2.

[0107] In summary, the present invention can ensure the reliability of the current sharing monitoring function in scenarios with multiple pressure limiter columns in parallel, and can greatly reduce system costs.

[0108] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0110] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0111] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0112] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for assembling voltage limiter columns in a DC controllable energy dissipation device, characterized in that, include: The configuration data of the voltage limiter of the DC controllable energy dissipation device is obtained. The voltage limiter configuration data includes the total number of parallel voltage limiter columns, the number of series valves in each voltage limiter column, and the total current flowing through the voltage limiter under overvoltage conditions of the protected equipment. The DC controllable energy dissipation device includes multiple parallel voltage limiter columns, and each voltage limiter column includes multiple series valves. The multiple parallel voltage limiter columns are divided into multiple voltage limiter column groups, and each voltage limiter column group is respectively equipped with a current sensor. The output terminals of all current sensors are respectively connected to a current sharing monitoring device. An electromagnetic transient simulation model of a DC controllable energy dissipation device is built based on the voltage limiter configuration data. The electromagnetic transient simulation model was used to simulate the breakdown and short circuit of a single valve plate in a single voltage limiter column, and the current of each voltage limiter column was obtained. Calculate the ratio between the current in the short-circuit voltage limiter column and the current in other voltage limiter columns; Based on the aforementioned multiple relationship and the preset current distribution coefficient setting value, determine the number of voltage limiter columns in each group of voltage limiter columns in the DC controllable energy dissipation device, as well as the number of voltage limiter column groups. The pressure relief column assembly method also includes: S1. Based on the currently determined number of pressure limiter column groups and the number of pressure limiter columns in each group, group the pressure limiter columns in the electromagnetic transient simulation model. S2, for at least one of the voltage limiter column groups, simulate the breakdown and short circuit of a single valve plate in a single voltage limiter column under overvoltage conditions of the protected equipment, and obtain the current of each voltage limiter column in the current voltage limiter column group; S3, Calculate the current distribution coefficient of the voltage limiter column group based on the current of each voltage limiter column in the current voltage limiter column group and the average current of a single column of all voltage limiter columns. S4, determine whether the calculated current distribution coefficient meets the preset alarm range and whether the duration meets the preset duration threshold: If all conditions are met, the number of pressure limiter columns and the number of pressure limiter column groups in each current pressure limiter column group will be determined as the optional pressure limiter column grouping scheme. If any condition is not met, the number of voltage limiter columns in each group of voltage limiter columns is reduced by 1, and the number of voltage limiter column groups is calculated accordingly. After updating the voltage limiter column grouping scheme, the process returns to steps S1-S4 until the calculated current distribution coefficient meets the preset alarm range and the duration meets the preset duration threshold, thus obtaining the optional voltage limiter column grouping scheme.

2. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 1, characterized in that, The current sensor uses an optical current transformer to collect the current flowing through the corresponding voltage limiter column group and is installed at the high-voltage end of the corresponding voltage limiter column group.

3. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 2, characterized in that, The rated voltage value of the current sensor The voltage reference value is selected according to the following formula. The value obtained after rounding up: In the formula, This indicates the number of parallel columns within a single pressure relief column group. This indicates the total current flowing through the voltage limiter when the protected equipment experiences an overvoltage. This indicates the total number of parallel voltage limiter columns in a DC controllable energy dissipation device.

4. The method for assembling voltage limiter columns of the DC controllable energy dissipation device according to claim 1, characterized in that, In S3, based on the current of each voltage limiter column in the current voltage limiter column group and the average current of a single column of all voltage limiter columns, the current distribution coefficient of the voltage limiter column group is calculated. The formula is as follows: In the formula, This is the group number of the pressure relief column assembly. Indicates that for the first The current distribution coefficient of the voltage limiter column group is simulated when a single valve plate in a single voltage limiter column breaks down and short-circuits the voltage limiter column. Indicates the flow through the first The current of each voltage limiter column group This represents the average current of a single voltage limiter in all voltage limiter columns, and has... This represents the average current of a single-column voltage limiter. This represents the number of parallel pressure limiter columns within the k-th pressure limiter column group.

5. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 1, characterized in that, For each voltage limiter column group in the voltage limiter column grouping scheme, the current distribution coefficient is obtained by simulating the breakdown and short circuit of a single valve plate in a single voltage limiter column under overvoltage conditions of the protected equipment: If the current distribution coefficient obtained by simulation for each voltage limiter column group meets the preset alarm range and the duration meets the preset duration threshold, then the current voltage limiter column grouping scheme is determined as the final voltage limiter column grouping scheme.

6. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 1, characterized in that, Assuming the total number of parallel pressure limiter columns in the pressure limiter configuration data is: The number of valve plates connected in series in each pressure limiter is The total current flowing through the voltage limiter under overvoltage conditions of the protected equipment is ; The electromagnetic transient simulation model of the DC controllable energy dissipation device built based on the voltage limiter configuration data includes: In the electromagnetic simulation transient model of the pressure limiter, the volt-ampere characteristic of one of the pressure limiter columns is set as (s-1) series valve plates, and the remaining (p-1) pressure limiter columns are set as s series valve plates.

7. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 1, characterized in that, Assuming the total number of parallel pressure limiter columns in the pressure limiter configuration data is: The number of valve plates connected in series in each pressure limiter is The total current flowing through the voltage limiter under overvoltage conditions of the protected equipment is ; In step S2, for the first In a simulation of a single voltage limiter column group, where a single valve plate in a single voltage limiter column breaks down and short-circuits the voltage limiter column under overvoltage conditions of the protected equipment, the electromagnetic transient simulation model of the DC controllable energy dissipation device is configured as follows: The first The volt-ampere characteristic of one pressure relief column in a pressure relief column group is set according to (s-1) series valve plates, and the remaining pressure relief columns are set according to s series valve plates.

8. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 6 or 7, characterized in that, The process of simulating the breakdown and short-circuiting of a single valve plate in a single voltage limiter column using the electromagnetic transient simulation model to obtain the current in each voltage limiter column includes: Make the total current The current flows through all the voltage limiter columns. Simulate the voltage limiter column containing (s-1) series valves where a single valve breaks down and short-circuits the voltage limiter column, and obtain the current of each voltage limiter column at this time.

9. The method for assembling voltage limiter columns of the DC controllable energy dissipation device according to claim 1, characterized in that, The determination of the number of voltage limiter columns in each group of voltage limiter columns in the DC controllable energy dissipation device, and the number of voltage limiter column groups, includes: Calculate the reference value for the maximum number of columns within a single pressure relief unit using the following formula. : In the formula, This indicates that the current in the short-circuit voltage limiter column is equal to the current in the other voltage limiter columns. times, This indicates the preset current distribution coefficient setting value; Based on the maximum column reference value Determine the number of parallel columns for each group of pressure relief columns. ; Based on the number of parallel columns in each group of pressure relief columns The total number of parallel pressure relief column columns determines the number of pressure relief column groups.

10. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 9, characterized in that, The reference value of the maximum number of columns Determine the number of parallel columns for each group of pressure relief columns. ,include: For the maximum number of columns reference value Rounding operation to obtain an integer This is used as the number of parallel columns for each group of pressure relief columns. .

11. The method for assembling the voltage limiter columns of the DC controllable energy dissipation device according to claim 9, characterized in that, The reference value of the maximum number of columns Determine the number of parallel columns for each group of pressure relief columns. ,include: For the maximum number of columns reference value Rounding operation to obtain an integer ; Determine the number of parallel columns in each group of pressure relief columns. for: ,in, This indicates the preset column margin.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for matching the voltage limiter columns of the DC controllable energy dissipation device as described in any one of claims 1-11.

Images