Equivalent test circuit and test method of hybrid multi-port direct current circuit breaker

Abstract

The invention provides an equivalent test circuit and test method of a hybrid multi-port direct current circuit breaker, and an equivalent transfer branch, an equivalent energy consumption branch, a first equivalent switch branch and a second equivalent switch branch of the equivalent test circuit are connected in parallel and are all connected between a first port and a second port. A hybrid multi-port direct current circuit breaker is simplified into an equivalent test circuit with only two ports, functions of all transfer branches and energy consumption branches in the multi-port direct current circuit breaker are integrated through the equivalent transfer branch and the equivalent energy consumption branch, all ports and branches do not need to be re-etched, hardware investment and occupied area of a test platform are greatly reduced, and the test efficiency is improved. Meanwhile, only the first equivalent switch branch and the second equivalent switch branch which are directly related to the fault port are reserved, complex logic of multi-port cooperative control is avoided, the building difficulty and the operation and maintenance cost of the test system are remarkably reduced, and the test period is shortened.

Description

Technical Field

[0001] This application belongs to the field of converter technology, and in particular relates to the equivalent test circuit and test method for hybrid multi-port DC circuit breakers. Background Technology

[0002] With the rapid development of flexible DC transmission and distribution networks and multi-terminal DC transmission systems, hybrid multi-port DC circuit breakers, as core protection devices, have become a key support for realizing large-scale grid connection of new energy sources and rapid isolation of grid faults due to their advantages of low on-state loss and fast breaking capacity.

[0003] However, the testing phase faces significant challenges during the research and development and mass production of hybrid multi-port DC circuit breakers. Multi-port DC circuit breaker topologies include multiple switching branches, transfer branches, and a common neutral point. Directly building a full-size test platform requires replicating the connection relationships of all ports and branches, resulting in high hardware costs, a large footprint, and complex collaborative control logic, thus significantly extending the testing cycle. Summary of the Invention

[0004] This application provides an equivalent test circuit and test method for a hybrid multi-port DC circuit breaker. It eliminates the need to replicate all ports and branches, significantly reducing the hardware investment and floor space required for the test platform. It also avoids the complex logic of multi-port collaborative control, significantly reducing the difficulty of building the test system and the cost of operation and maintenance, and shortening the test cycle.

[0005] In a first aspect, embodiments of this application provide an equivalent test circuit for a hybrid multi-port DC circuit breaker, the equivalent test circuit including: a first port, a second port, an equivalent transfer branch, an equivalent energy dissipation branch, a first equivalent switch branch, and a second equivalent switch branch; The equivalent transfer branch, the equivalent energy dissipation branch, the first equivalent switch branch, and the second equivalent switch branch are connected in parallel and are all connected between the first port and the second port. The first equivalent switch branch includes one or more first mechanical switches connected in series, and the second equivalent switch branch includes one or more second mechanical switches connected in series.

[0006] In some embodiments, the equivalent transfer branch includes N first transfer branches, each first transfer branch including one or more bidirectional solid-state switch modules connected in series; wherein (N-1) first transfer branches form a parallel structure, the parallel structure is connected in series with one first transfer branch, and N is an integer greater than or equal to 3.

[0007] In some embodiments, the first equivalent switching branch further includes a first inductor, and the second equivalent switching branch further includes a second inductor. The inductance values ​​of the first and second inductors are determined based on the current-carrying ratio of the first and second switching branches connected to the fault port in the hybrid multi-port DC circuit breaker. The current-carrying ratio is obtained by fault simulation of the hybrid multi-port DC circuit breaker and the DC system circuit network in which the hybrid multi-port DC circuit breaker is applied.

[0008] In some embodiments, the first equivalent inductance value of the first equivalent switch branch is the sum of the inductance value of the first mechanical switch and the inductance value of the first inductor, the second equivalent inductance value of the second equivalent switch branch is the sum of the inductance value of the second mechanical switch and the inductance value of the second inductor, and the ratio of the first equivalent inductance value to the second equivalent inductance value is the reciprocal of the current carrying ratio.

[0009] In some embodiments, the inductance of one of the first inductors and the second inductor is zero.

[0010] Secondly, embodiments of this application also provide a testing method for a hybrid multi-port DC circuit breaker. The equivalent test circuit of the hybrid multi-port DC circuit breaker is any of the equivalent test circuits provided in the first aspect embodiment. The first port of the equivalent test circuit is connected to the third port of the testing device, and the second port of the equivalent test circuit is connected to the fourth port of the testing device. The testing device includes a test current generating unit, a trigger switch unit, a data acquisition unit, and a controller. The test current generating unit, the trigger switch unit, and the data acquisition unit are all connected to the controller. The trigger switch unit is connected between the test current generating unit and the fourth port. The data acquisition unit is connected to the first equivalent switch branch, the second equivalent switch branch, the equivalent transfer branch, and the equivalent energy dissipation branch in the equivalent test circuit, respectively. The testing method includes: The test current generation unit is pre-charged. The control trigger switch unit is turned on, and the test current generation unit outputs the target test current required for the test. The target data for the corresponding branch is collected through the data acquisition unit; Based on the target data, determine the test results of the equivalent test circuit.

[0011] In some embodiments, the test current generating unit includes a charging power supply, a charging capacitor, and a first switch. A first terminal of the charging power supply is connected to a first input terminal of the charging capacitor via the first switch. A second terminal of the charging power supply is connected to a second input terminal of the charging capacitor. A first output terminal of the charging capacitor is first connected to a trigger switch, and a second output terminal of the charging capacitor is connected to a third port. Accordingly, controlling the test current generating unit to perform pre-charging includes: Determine the charging voltage of the charging power supply based on the target test current; When the first switch is closed, the charging capacitor is pre-charged. The first switch is disconnected when the voltage of the charging capacitor is greater than or equal to the first voltage threshold.

[0012] In some embodiments, the testing apparatus further includes a power-consuming unit that forms a circuit with a charging capacitor. The power-consuming unit includes a second switch and a power-consuming resistor connected in series. Accordingly, after determining the test results of the equivalent test circuit based on the target data, the testing method further includes: Close the second switch; If the voltage of the charging capacitor is less than or equal to the second voltage threshold, the second switch is disconnected.

[0013] In some embodiments, the trigger switch unit includes a first switch device and a second switch device, the first switch device and the second switch device are connected in anti-parallel, the target test current includes a first target test current and a second target test current, the current direction of the first target test current is opposite to the current direction of the second target test current, and correspondingly, controlling the trigger switch unit to conduct includes: When the target test current is the first target test current, control the first switching device to turn on and the second switching device to turn off. When the target test current is the second target test current, the second switching device is turned on and the first switching device is turned off.

[0014] Thirdly, embodiments of this application also provide a test system for a hybrid multi-port DC circuit breaker, the test system comprising: The testing device includes a third port, a fourth port, a test current generating unit, a trigger switch unit, a data acquisition unit, and a controller. The test current generating unit, the trigger switch unit, and the data acquisition unit are all connected to the controller. The trigger switch unit is connected between the test current generating unit and the fourth port. And any equivalent test circuit provided in the first aspect embodiment; The third port is connected to the first port of the equivalent test circuit, the fourth port is connected to the second port of the equivalent test circuit, and the data acquisition unit is connected to the first equivalent switch branch, the second equivalent switch branch, the equivalent transfer branch and the equivalent energy consumption branch in the equivalent test circuit, respectively. The controller is used to: control the test current generation unit to precharge; control the trigger switch unit to turn on, and the test current generation unit to output the target test current required for the test; collect the target data of the corresponding branch through the data acquisition unit; and determine the test results of the equivalent test circuit based on the target data.

[0015] The equivalent test circuit and test method for a hybrid multi-port DC circuit breaker provided in this application embodiment are as follows: the equivalent transfer branch, equivalent energy dissipation branch, first equivalent switch branch, and second equivalent switch branch of the equivalent test circuit are connected in parallel and are all connected between the first port and the second port. This simplifies the hybrid multi-port DC circuit breaker to an equivalent test circuit with only two ports. By integrating the functions of all transfer branches and energy dissipation branches in the multi-port DC circuit breaker through the equivalent transfer branch and equivalent energy dissipation branch, it is not necessary to replicate all ports and branches, which greatly reduces the hardware investment and floor space of the test platform. At the same time, only the first equivalent switch branch and the second equivalent switch branch directly related to the faulty port are retained, avoiding the complex logic of multi-port collaborative control, significantly reducing the difficulty of building the test system and the operation and maintenance cost, and shortening the test cycle. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the equivalent test circuit of a hybrid multi-port DC circuit breaker provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the hybrid multi-port DC circuit breaker under normal operating conditions provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the hybrid multi-port DC circuit breaker under fault conditions provided in the embodiments of this application; Figure 4 This is a schematic diagram of the equivalent transfer branch provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the test system for the hybrid multi-port DC circuit breaker provided in the embodiments of this application; Figure 6 This is a flowchart illustrating a testing method for a hybrid multi-port DC circuit breaker provided in an embodiment of this application. Detailed Implementation

[0018] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0019] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0020] In multi-terminal flexible DC power grids, DC circuit breakers are essential "safety switches" to ensure the safe and flexible operation of the system. DC circuit breakers can interrupt fault currents in milliseconds, preventing the spread of faults and damage to expensive equipment. By quickly isolating faulty lines, they can ensure the normal operation of the rest of the power grid, significantly reducing the scope of power outages. More importantly, DC short circuits enable flexible reconfiguration and reliable operation of the power grid, forming the cornerstone of building a true mesh DC power grid.

[0021] In multi-terminal DC power grids requiring a large number of circuit breakers, the total system cost would be excessively high if all circuit breakers were traditional two-port hybrid circuit breakers. To address this issue, researchers have previously proposed hybrid multi-port DC circuit breakers, such as... Figure 2 As shown, through an innovative topology, the cost of the solid-state switch on the second transfer branch 220 is reduced to less than half that of the traditional solution without affecting the fault current breaking performance, providing a key solution for the economical construction of DC power grids.

[0022] During the R&D phase of hybrid multi-port DC circuit breakers, the commutation and breaking speeds of the circuit breakers need to be verified. Only after the commutation and breaking speeds meet the application requirements can the hybrid multi-port DC circuit breakers be mass-produced. During testing, the positive terminal of the multi-port circuit breaker is typically used. If the overall unit fails to meet the application requirements during testing, it needs to be remanufactured, resulting in high time and material costs.

[0023] To address the aforementioned technical issues, this application provides an equivalent test circuit and test method for a hybrid multi-port DC circuit breaker. The equivalent test circuit replaces the hybrid multi-port DC circuit breaker for testing. The equivalent transfer branch, equivalent energy dissipation branch, first equivalent switch branch, and second equivalent switch branch of this equivalent test circuit are connected in parallel and are all connected between the first and second ports. This simplifies the hybrid multi-port DC circuit breaker to an equivalent test circuit with only two ports. By integrating the functions of all transfer and energy dissipation branches in the multi-port DC circuit breaker through the equivalent transfer and equivalent energy dissipation branches, it eliminates the need to replicate all ports and branches, significantly reducing the hardware investment and floor space required for the test platform. Furthermore, by retaining only the first and second equivalent switch branches directly related to the faulty port, the complex logic of multi-port collaborative control is avoided, significantly reducing the difficulty of building the test system and the cost of operation and maintenance, and shortening the test cycle.

[0024] This equivalent test circuit can accurately construct and reproduce the working conditions of a hybrid multi-port DC circuit breaker transmitting a short-circuit fault, so that the test conditions and test results can truly and accurately reflect the application scenarios of the hybrid multi-port DC circuit breaker in complex power grids, thereby verifying its reliability and providing a reliable basis for the development and application of the multi-port circuit breaker as a whole.

[0025] The equivalent test circuit of the hybrid multi-port DC circuit breaker provided in the embodiments of this application will be described below.

[0026] Figure 1 This is a schematic diagram of the equivalent test circuit of a hybrid multi-port DC circuit breaker provided in an embodiment of this application. For example... Figure 1 As shown, the equivalent test circuit 100 may include: a first port X, a second port Y, an equivalent transfer branch 110, an equivalent power consumption branch 120, a first equivalent switch branch 130, and a second equivalent switch branch 140.

[0027] The equivalent transfer branch 110, the equivalent energy dissipation branch 120, the first equivalent switch branch 130, and the second equivalent switch branch 140 are connected in parallel and are all connected between the first port X and the second port Y. The first equivalent switch branch 130 includes one or more first mechanical switches 131 connected in series, and the second equivalent switch branch 140 includes one or more second mechanical switches 141 connected in series.

[0028] by Figure 2 Taking the three-port DC circuit breaker shown as an example, the three-port DC circuit breaker includes three ports. Every two adjacent ports are connected by a switch branch 210. Each port is connected to the neutral point O through a second transfer branch 220. The neutral point O is the common connection point of multiple second transfer branches 220. A power dissipation branch 230 is connected in parallel to both ends of each second transfer branch 220. The switch branch 210 includes one or more mechanical switches 211 connected in series and a forced circulating current assembly 212 connected in series with the mechanical switches. Under normal operating conditions, the mechanical switches on all switch branches 210 are in the closed state, and the current between the ports flows through the switch branch 210.

[0029] When a short-circuit ground fault occurs at port B of the three-port DC circuit breaker, such as Figure 3 As shown, the mechanical switches 211 on the two switch branches 210 connected to port B are open, and all the second transfer branches 220 are turned on. The fault current flows from port A through the second transfer branch 220 to the neutral point O, and from port B through the second transfer branch 220 to the neutral point O. The currents on the two second transfer branches 220 are combined and flow from the neutral point O through the second transfer branch 220 to port C. Throughout the process, the mechanical switches 211 on the switch branch 210 between ports A and C are always in the on state. Ports A and C can be regarded as equipotential points. Therefore, the overall circuit connection can be regarded as the second transfer branch 220 between OA and the second transfer branch 220 between OC connected in parallel. After the two are connected in parallel, they are connected in series with the second transfer branch 220 between OB. The rated voltage level of each second transfer branch 220 is U / 2, so the overall rated voltage of the transfer branch is U / 2 + U / 2 = U. The two switch branches 210 connected to port B are connected in parallel, and the mechanical switches 211 on the corresponding switch branches 210 are also connected in parallel. When the voltage across the second transfer branch 220 reaches the operating voltage of the energy-consuming branch 230 connected in parallel, the fault current will commutate the second transfer branch 220 to the corresponding energy-consuming branch 230. Under the action of the energy-consuming branch 230, the voltage between the ports of the hybrid multi-port DC circuit breaker is limited, and the fault current gradually decreases until it reaches zero, thus achieving the isolation of the faulty port.

[0030] Based on the above analysis, the first port X of the equivalent test circuit 100 can be equivalent to the fault port of the hybrid multi-port DC circuit breaker, and the second port Y can be equivalent to the remaining ports of the hybrid multi-port DC circuit breaker excluding the fault port. For example, if the hybrid multi-port DC circuit breaker includes M ports, where M is an integer greater than or equal to 3, the second port Y is equivalent to (M-1) ports of the hybrid multi-port DC circuit breaker excluding the fault port.

[0031] The first equivalent switch branch 130 and the second equivalent switch branch 140 are respectively equivalent to two switch branches 210 connected to the fault port, and the first equivalent switch branch 130 and the second equivalent switch branch 140 are connected in parallel. Figure 3 Taking the three-port DC circuit breaker shown as an example, the first equivalent switch branch 130 and the second equivalent switch branch 140 are respectively equivalent to the switch branch 210 between ports AB and the switch branch 210 of the BC port component. The first mechanical switch 131 and the second mechanical switch 141 are equivalent to the mechanical switch 211 on the hybrid multi-port DC circuit breaker, and are used to control the conduction and cutoff of the corresponding equivalent switch branches.

[0032] The equivalent energy dissipation branch 120 is equivalent to the energy dissipation branch 230 in a hybrid multi-port DC circuit breaker. The equivalent energy dissipation branch 120 may include a metal oxide varistor (MOV). The MOV is an overvoltage protection device with non-linear voltage-resistance characteristics. Under normal voltage, the MOV exhibits a high-resistance state: when the circuit is at its normal operating voltage, the MOV's resistance is extremely high (reaching megaohms) and its leakage current is extremely low (reaching microamperes), hardly affecting the normal operation of the circuit, essentially acting as an "open circuit." Under overvoltage, the MOV exhibits a low-resistance conduction state: when an overvoltage occurs and the voltage exceeds the MOV's threshold voltage (i.e., the varistor voltage), its resistance decreases sharply, dropping to the ohm or even milliohm level, allowing a large current to pass instantaneously, clamping the overvoltage within a safe range, and preventing damage to downstream equipment due to overvoltage. Simultaneously, the MOV also has a self-recovery characteristic after the overvoltage disappears. When the overvoltage disappears and the voltage drops back to the normal range, the MOV's resistance automatically returns to a high resistance state, returning to the "open circuit" mode, and it can continue to work without manual intervention.

[0033] The equivalent transfer branch 110 is equivalent to the topology of all the second transfer branches 220 in the hybrid multi-port DC circuit breaker.

[0034] As an example, such as Figure 4 As shown, the equivalent transfer branch 110 includes N first transfer branches 111, each of which includes one or more bidirectional solid-state switch modules connected in series. (N-1) first transfer branches 111 form a parallel structure, which is connected in series with one first transfer branch 111. N is an integer greater than or equal to 3. The equivalent transfer branch 110 in this equivalent test circuit replicates the connection relationship between multiple second transfer branches 220 and the neutral point O in a hybrid multi-port DC circuit breaker, ensuring that the current transfer path, impedance characteristics, and synergistic effect are consistent with the actual transfer branches.

[0035] It should be noted that, Figure 2 (or Figure 3The example shown is only illustrative of a hybrid multi-port DC circuit breaker that is a three-port DC circuit breaker. The equivalent transfer branch 110 of its corresponding equivalent test circuit also includes three first transfer branches 111, two of which are connected in parallel, and then connected in series with the remaining first transfer branch 111. Similarly, when the hybrid multi-port DC circuit breaker is an N-port DC circuit breaker, the topology of the equivalent transfer branch 110 is: (N-1) first transfer branches 111 connected in parallel, and then connected in series with the remaining first transfer branch 111.

[0036] The first transfer branch 111 has the same structural composition as the second transfer branch 220, and may include one or more bidirectional solid-state switch modules connected in series. Figure 2 Or, as in 3, each second transfer branch 220 includes one or more bidirectional solid-state switch modules 221 connected in series.

[0037] The first transfer branch 111 is equipped with a bidirectional solid-state switch module, which matches the bidirectional current transfer capability of the second transfer branch 220. It can accurately simulate the current distribution pattern between different transfer branches during a fault, thereby improving the accuracy of current transfer performance testing.

[0038] It should be noted that, Figure 2 and Figure 3 The illustrated topology of the bidirectional solid-state switch module is a diode bridge structure, but it does not constitute a limitation on the equivalent test circuit of the hybrid multi-port DC circuit breaker provided in the embodiments of this application. Other structures known to those skilled in the art, such as reverse series or reverse parallel structures, may also be used in other practical ways, and are not limited herein.

[0039] The equivalent test circuit 100 provided in this application embodiment can accurately reproduce the working condition of a hybrid multi-port DC circuit breaker transmitting a short-circuit fault. The specific process is as follows: the first port X is equivalent to port B where a short-circuit fault occurs, and the second port Y is equivalent to ports A and C of the hybrid multi-port DC circuit breaker. When a short-circuit fault occurs at port B, the first mechanical switch 131 on the first equivalent switch branch 130 and the second mechanical switch 141 on the second equivalent switch branch 140 are both disconnected, and the equivalent transfer branch 110 is turned on. The fault current (target test current) flows through the equivalent transfer branch 110. When the voltage across the equivalent transfer branch 110 reaches the operating voltage of the equivalent energy dissipation branch 120 connected in parallel with it, the fault current will commutate the equivalent transfer branch 110 to the equivalent energy dissipation branch 120. Under the action of the equivalent energy dissipation branch 120, the voltage between the first port X and the second port Y is limited, and the fault current gradually decreases until it finally drops to zero. Using this equivalent test circuit to replace the hybrid multi-port DC circuit breaker for testing allows the test conditions and results to truly and accurately reflect the application scenarios of the hybrid multi-port DC circuit breaker in complex power grids, thereby verifying its reliability and providing a credible basis for the development and application of the hybrid multi-port DC circuit breaker as a whole.

[0040] The equivalent test circuit for the hybrid multi-port DC circuit breaker provided in this application replaces the hybrid multi-port DC circuit breaker for testing. The equivalent transfer branch, equivalent energy dissipation branch, first equivalent switch branch, and second equivalent switch branch of the equivalent test circuit are connected in parallel and are all connected between the first port and the second port. This simplifies the hybrid multi-port DC circuit breaker to an equivalent test circuit with only two ports. By integrating the functions of all transfer branches and energy dissipation branches in the multi-port DC circuit breaker through the equivalent transfer branch and equivalent energy dissipation branch, it is not necessary to replicate all ports and branches, which greatly reduces the hardware investment and floor space of the test platform. At the same time, only the first equivalent switch branch and the second equivalent switch branch directly related to the faulty port are retained, avoiding the complex logic of multi-port collaborative control, significantly reducing the difficulty of building the test system and the operation and maintenance cost, and shortening the test cycle.

[0041] In some embodiments, such as Figure 1 As shown, the first equivalent switching branch 130 also includes a first inductor 132, and the second equivalent switching branch 140 also includes a second inductor 142. The inductance values ​​of the first inductor 132 and the second inductor 142 are determined based on the current carrying ratio of the first switching branch and the second switching branch connected to the fault port in the hybrid multi-port DC circuit breaker. The current carrying ratio is obtained by fault simulation of the hybrid multi-port DC circuit breaker and the DC system circuit network used by the hybrid multi-port DC circuit breaker.

[0042] Among them, by performing fault simulation on the hybrid multi-port DC circuit breaker and the DC system circuit network it is applied to, the current carrying capacity of the first switch branch and the second switch branch can be obtained, and then the current carrying capacity ratio of the first switch branch and the second switch branch can be obtained to reflect the real fault conditions.

[0043] Combination Figure 3 Taking the short-circuit ground fault at port B of the three-port DC circuit breaker as an example, considering the differences in system characteristics between port A and port C, the current carrying capacity of the two switch branches connected to port B (i.e., the first switch branch and the second switch branch) may be inconsistent.

[0044] In this embodiment, by adding a first inductor 132 and a second inductor 142 to the first equivalent switch branch 130 and the second equivalent switch branch 140 respectively, and adjusting the inductance values ​​of the first inductor 132 and the second inductor 142 according to the current ratio of the two switch branches adjacent to the fault port in the hybrid multi-port DC circuit breaker, the current distribution law of the equivalent switch branch is consistent with that of the actual switch branch, which is closer to the real operating condition. In addition, the introduction of the first inductor 132 and the second inductor 142 also simulates the distributed inductance of the real switch branch, making the transient rise rate and peak characteristics of the test current consistent with the actual fault current, thus ensuring the authenticity of the circuit breaker breaking capacity test.

[0045] In some embodiments, the first equivalent inductance value of the first equivalent switch branch 130 is the sum of the inductance value of the first mechanical switch and the inductance value of the first inductor, and the second equivalent inductance value of the second equivalent switch branch 140 is the sum of the inductance value of the second mechanical switch and the inductance value of the second inductor. The ratio of the first equivalent inductance value to the second equivalent inductance value is the reciprocal of the current carrying ratio.

[0046] According to Kirchhoff's laws, in the equivalent test circuit, the current ratio of the first equivalent switching branch 130 to the second equivalent switching branch 140 is approximately the inverse ratio of the inductance values ​​of the two equivalent switching branches. For example, if the current ratio of the first equivalent switching branch 130 to the second equivalent switching branch 140 is 1:2, then the ratio of the first equivalent inductance value to the second equivalent inductance value is 2:1.

[0047] The first mechanical switch 131 and the second mechanical switch 141 have stray inductances. The first equivalent inductance of the first equivalent switch branch 130 is the inductance of the first mechanical switch 131 and the inductance of the first inductor 132. The second equivalent inductance of the second equivalent switch branch 140 is the inductance of the second mechanical switch 141 and the inductance of the second inductor 142. The first equivalent inductance and the second equivalent inductance satisfy formula (1): (L) K1 +L1) / (L K2 +L2) = I2 / I1 (1) Among them, L K1 L1 represents the inductance value of the first mechanical switch 131, and L2 represents the inductance value of the first inductor 132. K2 L1 represents the inductance value of the second mechanical switch 141, L2 represents the inductance value of the second inductor 142, I1 represents the current value of the first equivalent switch branch 130, and I2 represents the current value of the second equivalent switch branch 140.

[0048] This embodiment is based on the rule that "the ratio of the first equivalent inductance value to the second equivalent inductance value is the reciprocal of the current ratio". After determining the current ratio of the actual switching branch, the inductance values ​​of the first inductor 132 and the second inductor 142 can be calculated without complex simulation, which accelerates the parameter calibration efficiency of the test platform. It also realizes the precise and controllable current distribution of the equivalent switching branch, avoids the current deviation between the equivalent circuit and the actual switching branch, and improves the reliability of the test data.

[0049] In some embodiments, the inductance of one of the first inductors and the second inductor is zero.

[0050] In this embodiment, the inductance value of one of the first inductors and the second inductor is allowed to be zero. This can be adapted to scenarios where the distributed inductance of a certain switch branch in an actual switch branch can be ignored, avoiding unnecessary inductor redundancy and improving the adaptability and simplicity of the equivalent circuit. At the same time, reducing unnecessary inductor components further simplifies the hardware configuration of the test platform and helps to save costs.

[0051] For example, taking the case where the inductance value L1 of the first inductor is zero, the inductance value L2 of the second inductor can be determined by combining formula (1). The inductance value L2 is a unique value.

[0052] Based on the equivalent test circuit of the combined multi-port DC circuit breaker provided in the above embodiments, this application also provides a specific implementation of a test system for a hybrid multi-port DC circuit breaker. Please refer to the following embodiments.

[0053] See Figure 5 The test system for hybrid multi-port DC circuit breakers provided in this application includes: a test device and any of the equivalent test circuits 100 provided in the above embodiments.

[0054] The testing device includes a third port, a fourth port, a test current generating unit 310, a trigger switch unit 320, a data acquisition unit (not shown in the figure), and a controller (not shown in the figure). The test current generating unit 310, the trigger switch unit 320, and the data acquisition unit are all connected to the controller. The trigger switch unit 320 is connected between the test current generating unit 310 and the fourth port.

[0055] The third port of the testing device is connected to the first port of the equivalent test circuit 100, and the fourth port is connected to the second port of the equivalent test circuit 100. The data acquisition unit is connected to the first equivalent switching branch, the second equivalent switching branch, the equivalent transfer branch, and the equivalent energy dissipation branch in the equivalent test circuit, respectively. The data acquisition unit may include voltage sensors and current sensors to acquire the voltage waveform or current waveform of each branch. The data acquisition unit covers all branches and can simultaneously verify core indicators such as the switching or breaking time of the circuit breaker, providing comprehensive data support for circuit breaker performance optimization.

[0056] The controller is used to: control the test current generating unit 310 to perform pre-charging; control the trigger switch unit 320 to turn on, and the test current generating unit 310 to output the target test current required for testing; collect the target data of the corresponding branch through the data acquisition unit; and determine the test results of the equivalent test circuit based on the target data.

[0057] The test system for hybrid multi-port DC circuit breakers provided in this application integrates the test device with the equivalent test circuit to automate the entire test process. The controller uniformly schedules pre-charging, triggering testing, data acquisition, and result determination, reducing human error and improving the consistency and repeatability of test data.

[0058] In some embodiments, such as Figure 5 As shown, the test current generating unit 310 includes a charging power supply 311 and a charging capacitor C. charge With the first switch K1, the first terminal of the charging power supply 311 is connected to the charging capacitor C through the first switch K1. charge The first input terminal is connected, and the second terminal of the charging power supply 311 is connected to the charging capacitor C. charge The second input terminal is connected to the charging capacitor C. charge The first output terminal is connected to the trigger switch unit 320, and the charging capacitor C charge The second output terminal is connected to the third port. The controller is also used to: determine the charging voltage of the charging power supply based on the target test current; close the first switch to precharge the charging capacitor; and open the first switch if the voltage value of the charging capacitor is greater than or equal to a first voltage threshold.

[0059] In some embodiments, such as Figure 5 As shown, the testing device also includes a power consumption unit 330, which is connected to a charging capacitor C. charge Forming a circuit, the energy-consuming unit 330 includes a second switch K2 and an energy-consuming resistor R connected in series. Accordingly, after determining the test results of the equivalent test circuit based on the target data, the controller is also used to: close the second switch K2, causing the charging capacitor C to... charge The reverse energy is dissipated in the energy-consuming resistor R; and in the charging capacitor C.charge If the voltage value is less than or equal to the second voltage threshold, it indicates that the charging capacitor C charge Once the energy has been released, disconnect the second switch K2, and the testing device can continue to wait for the next test.

[0060] In some embodiments, such as Figure 5 As shown, the trigger switch unit 320 includes a first switch device 321 and a second switch device 322. The first switch device 321 and the second switch device 322 are connected in parallel in reverse. The target test current includes a first target test current and a second target test current. The current direction of the first target test current is opposite to that of the second target test current. The controller is also used to: control the first switch device to turn on and the second switch device to turn off when the target test current is the first target test current; and control the second switch device to turn on and the first switch device to turn off when the target test current is the second target test current.

[0061] In some embodiments, such as Figure 5 As shown, the test device also includes an inductor L, which is connected between the fourth port and the test current generating unit.

[0062] Inductor L and charging capacitor C in the test device charge The LC transient circuit is formed, and the charging capacitor C charge During discharge, the inductor L stores magnetic field energy, and the current flows through the charging capacitor C. charge A transient oscillation is formed between the inductor L and the circuit breaker, ensuring that the target test current can be maintained for a sufficient time, allowing the circuit breaker ample time for response, commutation, and breaking, thus fully verifying its fault isolation capability. The inductor L in the test device also replicates the inductance parameters of the actual system, allowing the charging capacitor C to... charge The fault current waveform generated by the discharge is consistent with the current characteristics of a real short-circuit fault, ensuring that the test conditions closely resemble actual application scenarios.

[0063] Based on the above embodiments, this application also provides a specific implementation of a testing method for a hybrid multi-port DC circuit breaker. Please refer to the following embodiments.

[0064] Combination Figure 5The first port of the equivalent test circuit 100 is connected to the third port of the test device, and the second port of the equivalent test circuit 100 is connected to the fourth port of the test device. The test device includes a test current generating unit 310, a trigger switch unit 320, a data acquisition unit, and a controller. The test current generating unit 310, the trigger switch unit 320, and the data acquisition unit are all connected to the controller. The trigger switch unit is connected between the test current generating unit and the fourth port. The data acquisition unit is connected to the first equivalent switch branch, the second equivalent switch branch, the equivalent transfer branch, and the equivalent energy dissipation branch in the equivalent test circuit, respectively.

[0065] like Figure 6 As shown, the test method for this hybrid multi-port DC circuit breaker may include the following steps: S110~S140.

[0066] S110, control the test current generation unit to perform pre-charging.

[0067] Specifically, the test current generating unit 310 includes a charging power supply 311 and a charging capacitor C. charge With the first switch K1, the first terminal of the charging power supply 311 is connected to the charging capacitor C through the first switch K1. charge The first input terminal is connected, and the second terminal of the charging power supply 311 is connected to the charging capacitor C. charge The second input terminal is connected to the charging capacitor C. charge The first output terminal is connected to the trigger switch unit 320, and the charging capacitor C charge The second output terminal is connected to the third port.

[0068] Accordingly, S110 may include the following steps: determining the charging voltage of the charging power supply 311 based on the target test current; closing the first switch K1 to close the charging capacitor C. charge Pre-charge is performed; in the charging capacitor C charge If the voltage value is greater than or equal to the first voltage threshold, the first switch K1 is disconnected.

[0069] The charging power supply 311 is a DC power supply with an adjustable charging voltage. The charging voltage can be determined according to the target test current (simulated fault current) required for testing, so the test current generating unit 310 can generate currents of different amplitudes to meet the testing requirements of different fault levels. As an example, the charging power supply 311 may include a charger.

[0070] In this step, the first switch K1 is closed, and the charging power supply 311 and the charging capacitor C are connected. charge The circuit is open, and the charging power supply 311 supplies power to the charging capacitor C. charge Pre-charging is performed at the charging capacitor C. chargeIf the voltage value is greater than or equal to the first voltage threshold, it indicates that the charging capacitor C charge Pre-charging is complete. Disconnect the first switch K1 to end pre-charging.

[0071] S120: Control the trigger switch unit to turn on, and the test current generation unit outputs the target test current required for the test.

[0072] In this step, after the trigger switch unit 320 is turned on, the loop between the test current generation unit 310 and the equivalent test circuit 100 is completed. The test current generation unit 310 outputs the target test current, which flows into the equivalent test circuit 100. The target test current refers to the fault current between the ports of the simulated hybrid multi-port DC circuit breaker under fault conditions.

[0073] As an example, such as Figure 5 As shown, the trigger switch unit 320 includes a first switch device 321 and a second switch device 322, which are connected in anti-parallel. The target test current includes a first target test current and a second target test current, with the current direction of the first target test current being opposite to that of the second target test current. Accordingly, "controlling the trigger switch unit to conduct" may include the following steps: when the target test current is the first target test current, controlling the first switch device to conduct and the second switch device to turn off; when the target test current is the second target test current, controlling the second switch device to conduct and the first switch device to turn off.

[0074] In this embodiment, the control logic of the first switching device 321 and the second switching device 322 is as follows: the switching device with the same current direction as the target test current required for the test is turned on, and the switching device with the opposite current direction to the target test current required for the test is turned off to avoid bidirectional current superposition interference.

[0075] S130, Collect target data for the corresponding branch through the data acquisition unit.

[0076] After the target test current flows into the equivalent test circuit 100, in response to the target test current, the mechanical switches on the first and second equivalent switching branches in the equivalent test circuit 100 are disconnected, and the current is switched to the equivalent transfer branch. In this step, the target data (which may include voltage or current) on the corresponding branch is collected using the data acquisition unit.

[0077] S140. Based on the target data, determine the test results of the equivalent test circuit.

[0078] This step determines the fault breaking capacity of the equivalent test circuit based on the target data. If the commutation time and breaking time meet the requirements, the fault breaking capacity of the hybrid multi-port DC circuit breaker corresponding to the equivalent test circuit is verified.

[0079] It should be noted that the trigger switch unit 320 will automatically turn off after the current crosses zero, and the test process will end.

[0080] The testing method for hybrid multi-port DC circuit breakers provided in this application achieves automated control of the test through a closed-loop process of pre-charging, triggering switch conduction, data acquisition, and result determination, reducing manual intervention and improving test efficiency and data reliability. At the same time, by utilizing the data acquisition unit to cover all key branches, it can simultaneously acquire full-process data of switch branch opening, transfer branch commutation, and energy absorption of energy-consuming branches, thus comprehensively testing the fault response, isolation, and clearing capabilities of the circuit breaker.

[0081] In some embodiments, such as Figure 5 As shown, the testing device also includes a power consumption unit 330, which is connected to a charging capacitor C. charge A circuit is formed. The energy-consuming unit 330 includes a second switch K2 and an energy-consuming resistor R connected in series. Accordingly, after S140, the test method may further include the following steps: closing the second switch K2; charging the capacitor C... charge If the voltage value is less than or equal to the second voltage threshold, disconnect the second switch K2.

[0082] In this embodiment, after the test process is completed, the power consumption unit 330 is used to charge the capacitor C. charge The remaining energy (especially reverse energy) is safely dissipated, avoiding the charging capacitor C. charge Safety risks caused by residual voltage; in charging capacitor C charge If the voltage value is less than or equal to the second voltage threshold, it indicates that the charging capacitor C charge Once the energy dissipation is complete, the second switch K2 is disconnected, and the testing device can quickly enter the next test, which helps to improve the cycle efficiency of the testing system.

[0083] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0084] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific operation processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. An equivalent test circuit of a hybrid multi-port DC circuit breaker, characterized in that, The equivalent test circuit comprises a first port, a second port, an equivalent transfer branch, an equivalent energy consumption branch, a first equivalent switch branch and a second equivalent switch branch. The equivalent transfer branch, the equivalent energy consumption branch, the first equivalent switch branch and the second equivalent switch branch are connected in parallel between the first port and the second port, the first equivalent switch branch comprises one or more first mechanical switches connected in series, and the second equivalent switch branch comprises one or more second mechanical switches connected in series.

2. The equivalent test circuit of claim 1, wherein, The equivalent transfer branch comprises N first transfer branches, each of the first transfer branches comprises one or more bidirectional solid state switch modules connected in series, (N-1) of the first transfer branches form a parallel structure, the parallel structure is connected in series with one of the first transfer branches, and N is an integer greater than or equal to 3.

3. The equivalent test circuit of claim 1, wherein, The first equivalent switch branch further comprises a first inductor, the second equivalent switch branch further comprises a second inductor, the inductance values of the first inductor and the second inductor are determined according to a current flow ratio of a first switch branch and a second switch branch connected with a fault port in the hybrid multi-port DC circuit breaker, and the current flow ratio is obtained by performing fault simulation on the hybrid multi-port DC circuit breaker and a DC system circuit network to which the hybrid multi-port DC circuit breaker is applied.

4. The equivalence test circuit of claim 3, wherein, A first equivalent inductance value of the first equivalent switch branch is a sum of an inductance value of the first mechanical switch and an inductance value of the first inductor, a second equivalent inductance value of the second equivalent switch branch is a sum of an inductance value of the second mechanical switch and an inductance value of the second inductor, and a ratio of the first equivalent inductance value to the second equivalent inductance value is reciprocal to the current flow ratio.

5. The equivalence test circuit of claim 4, wherein, The inductance value of one of the first inductor and the second inductor is zero.

6. A test method of a hybrid multi-port DC circuit breaker, characterized in that, The equivalent test circuit of the hybrid multi-port DC circuit breaker is the equivalent test circuit according to any one of claims 1-5, a first port of the equivalent test circuit is connected with a third port of a test device, a second port of the equivalent test circuit is connected with a fourth port of the test device, the test device comprises a test current generation unit, a trigger switch unit, a data acquisition unit and a controller, the test current generation unit, the trigger switch unit and the data acquisition unit are connected with the controller, the trigger switch unit is connected between the test current generation unit and the fourth port, and the data acquisition unit is connected with the first equivalent switch branch, the second equivalent switch branch, the equivalent transfer branch and the equivalent energy consumption branch in the equivalent test circuit respectively; and the test method comprises: controlling the test current generation unit to perform pre-charging; controlling the trigger switch unit to be turned on, and the test current generation unit to output a target test current required by the test; acquiring target data of corresponding branches by the data acquisition unit; determining a test result of the equivalent test circuit according to the target data.

7. The test method of claim 6, wherein, The test current generating unit comprises a charging power supply, a charging capacitor and a first switch, a first end of the charging power supply is connected with a first input end of the charging capacitor through the first switch, a second end of the charging power supply is connected with a second input end of the charging capacitor, a first output end of the charging capacitor is connected with the trigger switch unit, a second output end of the charging capacitor is connected with the third port, correspondingly, the control of the test current generating unit for pre-charging comprises: determining a charging voltage of the charging power supply according to the target test current; closing the first switch to pre-charge the charging capacitor; in the case that the voltage value of the charging capacitor is greater than or equal to a first voltage threshold, opening the first switch.

8. The test method of claim 7, wherein, The test device further comprises an energy consumption unit, the energy consumption unit forms a loop with the charging capacitor, the energy consumption unit comprises a second switch and an energy consumption resistor connected in series, correspondingly, after the determination of the test result of the equivalent test circuit according to the target data, the test method further comprises: closing the second switch; in the case that the voltage value of the charging capacitor is less than or equal to a second voltage threshold, opening the second switch.

9. The test method according to any one of claims 6-8, characterized in that, The trigger switch unit comprises a first switch device and a second switch device, the first switch device and the second switch device are connected in reverse parallel, the target test current comprises a first target test current and a second target test current, the current direction of the first target test current and the current direction of the second target test current are opposite, correspondingly, the control of the trigger switch unit for conduction comprises: in the case that the target test current is the first target test current, controlling the first switch device to be turned on and the second switch device to be turned off; in the case that the target test current is the second target test current, controlling the second switch device to be turned on and the first switch device to be turned off.

10. A test system for a hybrid multi-port DC circuit breaker, characterized in that, The test system comprises: a test device comprising a third port, a fourth port, a test current generating unit, a trigger switch unit, a data acquisition unit and a controller, the test current generating unit, the trigger switch unit and the data acquisition unit are connected with the controller, the trigger switch unit is connected between the test current generating unit and the fourth port; and the equivalent test circuit as claimed in any one of claims 1-5; wherein the third port is connected with the first port of the equivalent test circuit, the fourth port is connected with the second port of the equivalent test circuit, the data acquisition unit is connected with the first equivalent switch branch, the second equivalent switch branch, the equivalent transfer branch and the equivalent energy consumption branch in the equivalent test circuit respectively; the controller is used for controlling the test current generating unit for pre-charging, controlling the trigger switch unit for conduction, the test current generating unit outputting the target test current required by the test, collecting the target data of the corresponding branch through the data acquisition unit, and determining the test result of the equivalent test circuit according to the target data.

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