A multi-port dc circuit breaker equivalent breaking test device and method

Abstract

A multi-port DC circuit breaker equivalent breaking test device and method are disclosed. The device comprises an equivalent breaking test loop, a test product multi-port DC circuit breaker, a multi-port circuit breaker load impedance cabinet and a short-circuit fault simulation switch. The equivalent breaking test loop comprises an energy storage sub-circuit, an energy dissipation sub-circuit and an energy release sub-circuit. A main branch, a transfer branch and an energy consumption branch are connected in parallel. Transfer switches exist between multiple main branches and the transfer branch. The two ends of the transfer switch are electrically connected with the output end of the main branch and the output end of the transfer branch, respectively. The first signal output end of the test product multi-port DC circuit breaker is electrically connected with the signal input end of the multi-port circuit breaker load impedance cabinet. The second signal output end of the test product multi-port DC circuit breaker is electrically connected with the signal input end of the short-circuit fault simulation switch. The output end of the short-circuit fault simulation switch is electrically connected with the output end of the multi-port circuit breaker load impedance cabinet and the second signal output end of the equivalent breaking test loop.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible direct current power transmission, in particular to an equivalent breaking test device and method for a multi-port direct current circuit breaker. BACKGROUND

[0002] Direct current power systems play a crucial role in power transmission and distribution. Compared with alternating current power systems, direct current systems have various advantages, including lower transmission loss, better power quality control, higher power density, and better scalability. Therefore, direct current power systems are widely used in specific application fields, such as high-voltage power transmission, power interconnection, solar and wind power generation, electric vehicles, and data centers. A direct current circuit breaker is a key component in a direct current power system, which is used to break the current when the circuit is interrupted, faulty, or under maintenance. Among them, a multi-port direct current circuit breaker can use one transfer branch to realize the transfer of the current of multiple main branches, and has higher economy. When a short-circuit fault occurs, the multi-port direct current circuit breaker breaks the fault current of the fault branch, the current of each branch is transferred to the transfer branch, and the transfer branch simultaneously withstands the transient overvoltage, discharges the energy stored in the line inductance, and withstands the rated voltage after breaking.

[0003] The commonly used direct current circuit breaker breaking test methods at present generally include ideal power source method, LC oscillation method, and synthetic loop method. Among them, the ideal power source method needs to use a stable external power source, so the cost is relatively high. The LC oscillation method has relatively poor stability and accuracy of the test current due to the parameter changes of the test object and the influence of the external environment, as well as the voltage drop at both ends of the circuit breaker. The synthetic loop method adds a pre-charging capacitor, which increases the complexity of the test loop and may introduce additional costs. The above methods cannot completely realize the test requirements of the selective examination of the fault line of the multi-port circuit breaker.

[0004] The information disclosed in the background section is only used to enhance the understanding of the background of the present application, and therefore can contain information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] In view of the deficiencies or shortcomings of the prior art, a multi-port direct current circuit breaker equivalent breaking test device and method are provided, which improves the direct current breaking capacity of the multi-port direct current circuit breaker, can selectively examine the fault line, fully meets the requirements of the test current and test voltage of the current breaking test of the multi-port direct current circuit breaker, and has high equivalence.

[0006] The purpose of the present application is achieved by the following technical solutions.

[0007] A multi-port direct current circuit breaker equivalent breaking test device comprises an equivalent breaking test loop, a test multi-port direct current circuit breaker, a multi-port circuit breaker load impedance cabinet, and a short-circuit fault simulation switch, wherein,

[0008] The equivalent breaking test circuit comprises an energy storage sub-circuit, an energy dissipation sub-circuit and a discharge sub-circuit, the energy storage sub-circuit is connected in parallel with the energy dissipation sub-circuit, a first signal output end of the energy dissipation sub-circuit is electrically connected with an input end of the discharge sub-circuit, an output end of the discharge sub-circuit is electrically connected with a signal input end of the test multi-port DC circuit breaker, a second signal output end of the energy dissipation sub-circuit is grounded,

[0009] The test multi-port DC circuit breaker comprises a plurality of main branches, a transfer branch and an energy dissipation branch, the main branches, the transfer branch and the energy dissipation branch are connected in parallel, there is a transfer switch between the main branches and the transfer branch, the transfer switch is electrically connected with a main branch output end and a transfer branch output end respectively, a first signal output end of the test multi-port DC circuit breaker is electrically connected with a signal input end of a multi-port circuit breaker load impedance cabinet, a second signal output end of the test multi-port DC circuit breaker is electrically connected with a signal input end of a short-circuit fault simulation switch, and an output end of the short-circuit fault simulation switch is electrically connected with an output end of the multi-port circuit breaker load impedance cabinet and a second signal output end of the equivalent breaking test circuit.

[0010] In the equivalent breaking test device for the multi-port DC circuit breaker, the energy storage sub-circuit comprises a DC power supply, a charging switch and an energy storage capacitor, a positive electrode of the DC power supply is electrically connected with a first end of the charging switch, a second end of the charging switch is electrically connected with a positive electrode of the energy storage capacitor, and a negative electrode of the DC power supply and a negative electrode of the energy storage capacitor are grounded.

[0011] In the equivalent breaking test device for the multi-port DC circuit breaker, the energy dissipation sub-circuit comprises a discharge switch and a discharge resistor, two ends of the discharge switch are electrically connected with an input end of the discharge sub-circuit and a first end of the discharge resistor respectively, and a second end of the discharge resistor is grounded.

[0012] In the equivalent breaking test device for the multi-port DC circuit breaker, the discharge sub-circuit comprises an auxiliary switch and a resonance inductor, two ends of the auxiliary switch are connected with a first signal output end of the energy dissipation sub-circuit and a first end of the resonance inductor respectively, and a second end of the resonance inductor is electrically connected with a signal input end of the test multi-port DC circuit breaker.

[0013] In the equivalent breaking test device for the multi-port DC circuit breaker, the multi-port circuit breaker load impedance cabinet comprises load impedances on a plurality of main branches, and the load impedances are electrically connected with second output ends of the main branches and a second output end of a short-circuit fault simulation device respectively.

[0014] The test method of the equivalent breaking test device for the multi-port DC circuit breaker comprises the following steps,

[0015] The charging switch of the energy storage sub-circuit, the discharging switch of the energy releasing sub-circuit and the auxiliary switch of the discharging sub-circuit are in an open state;

[0016] At the first moment, the test multi-port DC circuit breaker is in a conducting state, the charging switch is closed, and the electric energy flows to the energy storage capacitor.

[0017] At the second moment, when the current rises to a preset amplitude, a main branch mechanical switch of the test multi-port DC circuit breaker starts to open, the transfer switch and the short-circuit fault simulation switch corresponding to the transfer branch are closed at the same time, then interact with the transfer branch, and under the current transfer effect, the fault current is quickly transferred from the mechanical switch to the transfer branch.

[0018] At the third moment, the main branch mechanical switch of the test multi-port DC circuit breaker extinguishes the arc, and after a certain delay, the transfer branch is controlled to be turned off, at this moment, the transient overvoltage appears at both ends of the test multi-port DC circuit breaker.

[0019] At the fourth moment, the energy consumption branch of the test multi-port DC circuit breaker acts until the bus current is zero, and the voltage at both ends of the test multi-port DC circuit breaker decreases and stabilizes at the rated DC voltage level of the system.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The present application improves the DC breaking capacity of the multi-port DC circuit breaker, can selectively examine the fault line, fully meets the requirements of the multi-port DC circuit breaker current breaking test on the test current and test voltage, and has high equivalence.

[0022] The above description is only a summary of the technical scheme of the present application, in order to make the technical means of the present application more clear and understandable, to the extent that the content of the specification can be implemented by the person skilled in the art, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are illustrated below. BRIEF DESCRIPTION OF DRAWINGS

[0023] Various other advantages and benefits of the present application will become apparent to those of ordinary skill in the art, upon reading the following detailed description of the preferred embodiment. The accompanying drawings are included to provide a better understanding of the preferred embodiment, and are not intended to limit the scope of the application. It should be readily understood that the drawings are not to scale, and are merely intended to depict the various embodiments of the application. As such, the drawings should not be construed as limiting the scope of the application.

[0024] In the drawings:

[0025] Fig. 1 A frame schematic diagram of a multi-port DC circuit breaker equivalent breaking test device provided for an embodiment of the present application;

[0026] Fig. 2 A structure schematic diagram of a multi-port DC circuit breaker equivalent breaking test device provided for an embodiment of the present application;

[0027] Fig. 3 A flow schematic diagram of a multi-port DC circuit breaker equivalent breaking test method provided for an embodiment of the present application;

[0028] Figs. 1-3 The symbols in the middle represent:

[0029] T - test multi-port DC circuit breaker, U - DC power supply, K0 - charging switch, C1 - energy storage capacitor, K1 - discharging switch, K2 - auxiliary switch, K3 - fault simulation switch, R1 - discharging resistor, L - resonant inductor, S1-SN - transfer switch.

[0030] The present application will be further explained with reference to the drawings and embodiments. DETAILED DESCRIPTION

[0031] Embodiments of the present application will be described more fully hereinafter with reference to the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0032] It should be noted that some terms are used in the description and claims to refer to particular components. One skilled in the art will understand that the same component can be referred to by different terms. This description and claims are not intended to be limited to the terms used. The description and claims are intended to cover all functional equivalents of the components. The description that follows is intended to illustrate preferred embodiments of the present application and is not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims.

[0033] In order to facilitate the understanding of the embodiments of the present application, the following will be further explained and described with several specific examples in conjunction with the accompanying drawings, and each drawing does not constitute a limitation on the embodiments of the present application.

[0034] In order to better understand, Figs. 1-3 As shown in the figure, an equivalent breaking test device of a multi-port DC circuit breaker includes an equivalent breaking test loop, a test multi-port DC circuit breaker, a multi-port circuit breaker load impedance cabinet and a short-circuit fault simulation switch, wherein,

[0035] The equivalent breaking test loop includes an energy storage sub-loop, an energy dissipation sub-loop and an energy release sub-loop. The energy storage sub-loop and the energy dissipation sub-loop are connected in parallel. The first signal output end of the energy dissipation sub-loop is electrically connected to the input end of the energy release sub-loop. The output end of the energy release sub-loop is electrically connected to the signal input end of the test multi-port DC circuit breaker. The second signal output end of the energy dissipation sub-loop is grounded.

[0036] The test multi-port DC circuit breaker includes a plurality of main branches, a transfer branch and an energy consumption branch. The main branches, the transfer branch and the energy consumption branch are connected in parallel. There is a transfer switch between the plurality of main branches and the transfer branch. The transfer switch is electrically connected to the output end of the main branch and the output end of the transfer branch. The first signal output end of the test multi-port DC circuit breaker is electrically connected to the signal input end of the multi-port circuit breaker load impedance cabinet. The second signal output end of the test multi-port DC circuit breaker is electrically connected to the signal input end of the short-circuit fault simulation switch. The output end of the short-circuit fault simulation switch is electrically connected to the output end of the multi-port circuit breaker load impedance cabinet and the second signal output end of the equivalent breaking test loop.

[0037] In the preferred embodiment of the multi-port DC circuit breaker equivalent breaking test device, the energy storage sub-loop includes a DC power supply, a charging switch and an energy storage capacitor. The positive electrode of the DC power supply is electrically connected to the first end of the charging switch. The second end of the charging switch is electrically connected to the positive electrode of the energy storage capacitor. The negative electrode of the DC power supply and the negative electrode of the energy storage capacitor are grounded.

[0038] In the preferred embodiment of the equivalent breaking test device of the multi-port DC circuit breaker, the energy releasing sub-circuit comprises a discharge switch and a discharge resistor, two ends of the discharge switch are electrically connected to the input end of the discharge sub-circuit and the first end of the discharge resistor respectively, and the second end of the discharge resistor is grounded.

[0039] In the preferred embodiment of the equivalent breaking test device of the multi-port DC circuit breaker, the discharge sub-circuit comprises an auxiliary switch and a resonant inductor, two ends of the auxiliary switch are connected to the first signal output end of the energy releasing sub-circuit and the first end of the resonant inductor respectively, and the second end of the resonant inductor is electrically connected to the signal input end of the test multi-port DC circuit breaker.

[0040] In the preferred embodiment of the equivalent breaking test device of the multi-port DC circuit breaker, the multi-port circuit breaker load impedance cabinet comprises load impedances on a plurality of main branches, and the load impedances are electrically connected to the second output ends of the plurality of main branches and the second output end of the short-circuit fault simulation device respectively.

[0041] The test method of the equivalent breaking test device of the multi-port DC circuit breaker comprises the following steps,

[0042] The charging switch of the energy storage sub-circuit, the discharge switch of the energy releasing sub-circuit, and the auxiliary switch of the discharge sub-circuit are in the open state;

[0043] At the first moment, the test multi-port DC circuit breaker is in the on state, the charging switch is closed, the electric energy flows to the energy storage capacitor, and once the charging is completed, the charging switch is opened to disconnect the current path, at this time, the auxiliary switch is closed, the energy storage capacitor generates a low-frequency oscillating sinusoidal current through the resonant inductor, and the current gradually rises;

[0044] At the second moment, when the current rises to a preset amplitude, the mechanical switch of one main branch of the test multi-port DC circuit breaker starts to open, the transfer switch corresponding to the transfer branch and the short-circuit fault simulation switch are closed at the same time, then interact with the transfer branch, and under the current transfer action, the fault current is quickly transferred from the mechanical switch to the transfer branch;

[0045] At the third moment, the arc of the mechanical switch of the main branch of the test multi-port DC circuit breaker is extinguished, and after a certain delay, the transfer branch is controlled to be turned off, at this time, the transient overvoltage appears at both ends of the test multi-port DC circuit breaker;

[0046] At the fourth moment, the energy dissipation branch of the test multi-port DC circuit breaker acts until the bus current goes to zero, and the voltage at both ends of the test multi-port DC circuit breaker drops and stabilizes at the rated DC voltage level of the system.

[0047] In one embodiment, the function of the energy storage sub-circuit is to charge the capacitor C1 through the power supply, and to generate a current through the resonance inductance L of the pre-charge capacitor C1 and the discharge branch to simulate a short-circuit current. The function of the energy discharge sub-circuit is to fully release the residual energy in the circuit after the opening is completed. The function of the discharge sub-circuit is to insert the resonance inductance L and isolate the energy storage sub-circuit and the test product multi-port DC circuit breaker T after opening, thereby improving safety. The function of the multi-port DC circuit breaker load impedance cabinet is to simulate the system load. The functions of the transfer switches S1-SN and the fault simulation switch K3 are to selectively examine the fault line and achieve more accurate fault simulation. As can be seen from the above embodiment, the embodiment provides a multi-port DC circuit breaker equivalent opening test device. By using the above implementation manner, the transfer switches and the short-circuit fault simulation switch can achieve fault simulation of any main branch, thereby achieving selective examination of the fault line, fully meeting the needs of the multi-port DC circuit breaker current opening test, and having high equivalence. By using the energy discharge sub-circuit and the discharge sub-circuit in cooperation, the residual energy in the circuit after the opening is fully released, and the discharge sub-circuit can isolate the energy storage sub-circuit and the test product multi-port DC circuit breaker after the opening, thereby having high safety.

[0048] Corresponding to the multi-port DC circuit breaker equivalent opening test device provided in the above embodiment, an embodiment of a multi-port DC circuit breaker equivalent opening test method is also provided in the present application. The embodiment uses the DC circuit breaker equivalent opening test device described in the above embodiment, as shown in Fig. 3 , the method comprises:

[0049] S101, the charging switch, the discharge switch and the auxiliary switch are in an open state.

[0050] S102, the multi-port circuit breaker is in a conducting state, the charging switch is closed, and the electric energy flows to the energy storage capacitor.

[0051] S103, once the charging is completed, the charging switch is opened to disconnect the current path. At this time, the auxiliary switch is closed, a low-frequency oscillating sinusoidal current is generated by the energy storage capacitor through the resonance inductance, and the current gradually increases.

[0052] S104, at a second time, when the current rises to a preset amplitude, a main branch mechanical switch of the test product multi-port DC circuit breaker starts to open, the transfer switch and the fault simulation switch of the corresponding branch are closed at the same time, then interact with the transfer branch, and under the action of the current transfer technology, the fault current is quickly transferred from the mechanical switch to the transfer branch.

[0053] S105, at a third time, the main branch mechanical switch of the test product DC circuit breaker extinguishes the arc, and after a certain delay, the core components in the transfer branch are turned off. At this time, a transient overvoltage appears between the two ends of the circuit breaker.

[0054] At S106, at the fourth moment, the circuit breaker energy consumption module acts until the bus current is zero. The voltage across the DC circuit breaker decreases and stabilizes at the rated DC voltage level of the system.

[0055] After the current is transferred, the fault main branch current will produce an artificial zero point, at which time the mechanical switch extinguishes the arc. At the same time, the test sample will withstand a transient overvoltage. When the voltage reaches the operating voltage of the arrester, the energy consumption branch is turned on and dissipates the remaining energy. In this process, the test device completes the breaking of the fault current of the entire multi-port DC circuit breaker, tests its resistance to transient overvoltage, and tests the performance of the energy consumption branch in absorbing energy.

[0056] During the test process, the transfer switch and the short-circuit fault simulation switch can realize fault simulation of any main branch, thereby realizing selective examination of the fault line and fully meeting the needs of the multi-port DC circuit breaker current breaking test, with high equivalence.

[0057] The above describes the basic principles of the present application in combination with specific embodiments, but it should be noted that the advantages, advantages, effects, etc. mentioned in the present application are only examples and are not limited, and these advantages, advantages, effects, etc. cannot be considered as the must-have of each embodiment of the present application. In addition, the above specific details are only for the purpose of example and for the purpose of understanding, and are not limited to the above specific details, and the present application is not limited to the above specific details.

[0058] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, alterations, changes, additions and sub-combinations thereof.

Claims

1. A test method for an equivalent breaking test device for a multi-port DC circuit breaker, characterized in that, The device includes an equivalent breaking test circuit, a multi-port DC circuit breaker for the test sample, a multi-port circuit breaker load impedance cabinet, and a short-circuit fault simulation switch, wherein... The equivalent breaking test circuit includes an energy storage sub-circuit, an energy discharge sub-circuit, and an electron discharge circuit. The energy storage sub-circuit and the energy discharge sub-circuit are connected in parallel. The first signal output terminal of the energy discharge sub-circuit is electrically connected to the input terminal of the electron discharge circuit. The output terminal of the electron discharge circuit is electrically connected to the signal input terminal of the multi-port DC circuit breaker of the test object. The second signal output terminal of the energy discharge sub-circuit is grounded. The test multi-port DC circuit breaker includes multiple main branches, transfer branches, and energy-consuming branches, which are connected in parallel. A transfer switch exists between the multiple main branches and the transfer branches. The two ends of the transfer switch are electrically connected to the output terminals of the main branches and the transfer branches, respectively. The first signal output terminal of the test multi-port DC circuit breaker is electrically connected to the signal input terminal of the multi-port circuit breaker load impedance cabinet. The second signal output terminal of the test multi-port DC circuit breaker is electrically connected to the signal input terminal of the short-circuit fault simulation switch. The output terminal of the short-circuit fault simulation switch is simultaneously electrically connected to the output terminal of the multi-port circuit breaker load impedance cabinet and the second signal output terminal of the equivalent breaking test circuit. The experimental method includes the following steps: The charging switch of the energy storage sub-circuit, the discharge switch of the energy dissipation sub-circuit, and the auxiliary switch of the discharge circuit are in the open state. At the first moment, the multi-port DC circuit breaker of the test sample is in the conducting state, the charging switch is closed, and the electrical energy flows to the energy storage capacitor. Once charging is completed, the charging switch is opened to disconnect the current path. At this time, the auxiliary switch is closed, and through the resonant inductor, the energy storage capacitor generates a low-frequency oscillating sinusoidal current, which gradually increases. At the second moment, when the current rises to the preset amplitude, one of the main branch mechanical switches of the multi-port DC circuit breaker of the test sample begins to open, and the transfer switch and short-circuit fault simulation switch of the corresponding transfer branch close simultaneously. Then, they interact with the transfer branch, and under the action of current transfer, the fault current is quickly transferred from the mechanical switch to the transfer branch. At the third moment, the main branch mechanical switch of the test multi-port DC circuit breaker extinguishes the arc. After a certain delay, the control transfer branch is turned off. At this time, a transient overvoltage occurs at both ends of the test multi-port DC circuit breaker. At the fourth moment, the energy-consuming branch of the multi-port DC circuit breaker of the test object operates until the bus current crosses zero, and the voltage across the multi-port DC circuit breaker of the test object drops and stabilizes at the rated DC voltage level of the system.

2. The method of claim 1, wherein, The energy storage sub-circuit includes a DC power supply, a charging switch, and an energy storage capacitor.

3. The method of claim 1, wherein, The energy dissipation sub-circuit includes a discharge switch and a discharge resistor.

4. The method of claim 1, wherein, The electron discharge circuit includes an auxiliary switch and a resonant inductor.

5. The method of claim 1, wherein, The multi-port circuit breaker load impedance cabinet includes load impedances on multiple main branches.

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