Testing device of direct current circuit breaker and stage difference verification method

Abstract

The invention provides a test device and a level difference verification method of a direct current circuit breaker, and the test device comprises a resistor module; the acquisition module is used for acquiring a first voltage of the direct-current circuit breaker when the test loop is switched off, and acquiring a second voltage of the direct-current circuit breaker when the test loop is switched on; and the control module is used for adjusting the resistance value of the resistance module until the current of the test loop reaches the rated current of the direct current circuit breaker when the test loop is conducted, and obtaining the short-circuit current of the direct current circuit breaker according to the rated current of the direct current circuit breaker, the first voltage and the second voltage. According to the test device of the direct current circuit breaker and the stage difference verification method, the resistance module with the adjustable resistance value is used for controlling the current intensity and voltage distribution, the voltage drop of the direct current circuit breaker is collected, and based on the Ohm law, the short-circuit current of the direct current circuit breaker can be calculated; and therefore, the short-circuit current of the direct-current circuit breaker can be fully verified.

Description

Technical Field

[0001] The present disclosure relates to the technical field, and in particular to a test device and a differential calibration method for a DC circuit breaker. Background Art

[0002] At present, the DC feeder network in the power system generally adopts a tree-like structure. From the battery to various power loads in the station, the conventional path involves a three-level distribution system, and DC circuit breakers are widely used as core protection equipment in each level of distribution. However, due to the failure to fully match the protection action characteristics between the upper and lower DC circuit breakers, when a short circuit occurs in the lower power equipment in the system, it is very easy to trigger the over-tripping phenomenon of the upper DC circuit breaker, which not only causes the accidental power outage of the non-fault feeder line, but may also cause a chain reaction to the key primary equipment of the substation (such as high-voltage switches, transformers, generators, etc.), causing a wider range of safety accidents.

[0003] Therefore, new and existing DC circuit breakers need to be fully tested and verified to ensure that the differential matching in the DC circuit is accurate, thereby ensuring the stable operation of the DC power supply system and preventing the spread of accidents and damage to equipment. Summary of the invention

[0004] The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, the purpose of the present disclosure is to provide a test device and a differential calibration method for a DC circuit breaker.

[0006] To achieve the above-mentioned purpose, the first aspect of the present disclosure provides a test device for a DC circuit breaker, comprising: a resistance module, wherein the resistance module and the DC circuit breaker are connected in parallel to form a test loop; a collection module, wherein a collection end of the collection module is arranged on the test loop, and the collection module is used to collect the current of the test loop, and when the test loop is disconnected, the collection module is used to collect the first voltage of the DC circuit breaker, and when the test loop is turned on, the collection module is used to collect the second voltage of the DC circuit breaker; a control module, wherein the control module is used to adjust the resistance value of the resistance module when the test loop is turned on until the current of the test loop reaches the rated current of the DC circuit breaker, and obtain the short-circuit current of the DC circuit breaker according to the rated current of the DC circuit breaker, the first voltage and the second voltage.

[0007] Optionally, the control module obtains the short-circuit current of the DC circuit breaker based on a first formula; wherein, the first formula is: Isc=U1×I / (U1-U2), Isc is the short-circuit current of the DC circuit breaker, I is the rated current of the DC circuit breaker, U1 is the first voltage, and U2 is the second voltage.

[0008] Optionally, the test device further includes: a switch module, the switch module is connected in series to the test loop, and the input end of the switch module is connected to the output end of the control module, and the control module is used to control the switch module to turn on or off the test loop.

[0009] Optionally, the test device also includes: a touch display module, the output end of the touch display module is connected to the input end of the control module, and the touch display module is used to input the rated current signal of the DC circuit breaker to the control module, so that the control module adjusts the resistance value of the resistance module according to the rated current of the DC circuit breaker; and the input end of the touch display module is connected to the output end of the control module, and the control module is used to input the short-circuit current signal of the DC circuit breaker to the touch display module, so that the touch display module displays the short-circuit current of the DC circuit breaker.

[0010] Optionally, the test device also includes: a start-stop module, the output end of the start-stop module is connected to the input end of the control module, and the start-stop module is used to input a start-stop signal to the control module so that the control module performs a start-stop action according to the start-stop signal.

[0011] Optionally, the test device also includes: a power supply module, the power supply end of the power supply module is connected to the power supply end of the external power supply, and the power supply end of the power supply module is respectively connected to the power supply end of the resistance module and the power supply end of the control module.

[0012] Optionally, the test device also includes: a test interface, the test interface and the resistance module are connected in parallel; a first wire, the first end of the first wire is connected to the first end of the test interface, and the second end of the first wire is connected to the first end of the DC circuit breaker; a second wire, the first end of the second wire is connected to the second end of the test interface, and the second end of the second wire is connected to the second end of the DC circuit breaker.

[0013] Optionally, the test device further includes: a test box, in which the resistance module, the acquisition module and the control module are respectively arranged.

[0014] A second aspect of the present disclosure provides a differential calibration method for a DC circuit breaker. The differential calibration method is based on a test device for a DC circuit breaker as provided in the first aspect of the present disclosure, and the differential calibration method comprises: obtaining a rated current of a lower-level DC circuit breaker; obtaining a short-circuit current of the lower-level DC circuit breaker in the test device according to the rated current of the lower-level DC circuit breaker; obtaining an instantaneous tripping current range of an upper-level DC circuit breaker, and comparing the short-circuit current of the lower-level DC circuit breaker with the instantaneous tripping current range of the upper-level DC circuit breaker; when the short-circuit current of the lower-level DC circuit breaker is within the instantaneous tripping current range of the upper-level DC circuit breaker, determining that there is a risk of over-tripping between the upper-level DC circuit breaker and the lower-level DC circuit breaker.

[0015] Optionally, the differential verification method also includes: obtaining an instantaneous tripping current range of the subordinate DC circuit breaker, and comparing the short-circuit current of the subordinate DC circuit breaker with the instantaneous tripping current range of the subordinate DC circuit breaker; when the short-circuit current of the subordinate DC circuit breaker is within the instantaneous tripping current range of the subordinate DC circuit breaker, judging that the subordinate DC circuit breaker is operating reliably.

[0016] The technical solution provided by the present disclosure may have the following beneficial effects:

[0017] When the test circuit is disconnected, the acquisition module acquires the first voltage when the DC circuit breaker is not connected in parallel with the resistance module, and when the test circuit is turned on, the control module adjusts the resistance value of the resistance module so that the current of the test circuit reaches the rated current of the DC circuit breaker. At the same time, the acquisition module acquires the second voltage after the DC circuit breaker is connected in parallel with the resistance module. Thus, the resistance module with adjustable resistance value is used to control the current intensity and voltage distribution. By acquiring the voltage drop of the DC circuit breaker and based on Ohm's law, the short-circuit current of the DC circuit breaker can be calculated, so as to facilitate full verification using the short-circuit current of the DC circuit breaker to ensure that the differential coordination in the DC circuit is accurate, thereby ensuring the stable operation of the DC power supply system and preventing the spread of accidents and damage to equipment.

[0018] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present disclosure will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 It is a structural schematic diagram of a DC circuit breaker test device proposed in an embodiment of the present disclosure;

[0021] Figure 2It is a wiring diagram of a test device of a DC circuit breaker provided in an embodiment of the present disclosure;

[0022] Figure 3 is an equivalent circuit diagram of a test device for a DC circuit breaker provided in an embodiment of the present disclosure;

[0023] Figure 4 It is a flow chart of a method for checking the level difference of a DC circuit breaker proposed in an embodiment of the present disclosure;

[0024] As shown in the figure: 1. Resistance module, 2. Acquisition module, 3. Control module, 4. Switch module, 5. Touch display module, 6. Start-stop module, 7. Power module, 8. Test interface, 9. First wire, 10. Second wire, 11. Test box, 12. DC circuit breaker. DETAILED DESCRIPTION

[0025] Embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and are not to be construed as limitations of the present disclosure. On the contrary, the embodiments of the present disclosure include all changes, modifications, and equivalents that fall within the spirit and connotation of the appended claims.

[0026] like Figure 1 and Figure 3 As shown, the embodiment of the present disclosure proposes a test device for a DC circuit breaker, including: a resistance module 1, a collection module 2 and a control module 3. The resistance module 1 and the DC circuit breaker 12 are connected in parallel to form a test loop. The collection end of the collection module 2 is set on the test loop, and the collection module 2 is used to collect the current of the test loop, and when the test loop is disconnected, the collection module 2 is used to collect the first voltage of the DC circuit breaker 12, and when the test loop is turned on, the collection module 2 is used to collect the second voltage of the DC circuit breaker 12. The control module 3 is used to adjust the resistance value of the resistance module 1 when the test loop is turned on until the current of the test loop reaches the rated current of the DC circuit breaker 12, and obtain the short-circuit current of the DC circuit breaker 12 according to the rated current, the first voltage and the second voltage of the DC circuit breaker 12.

[0027] It can be understood that when the test circuit is disconnected, the acquisition module 2 acquires the first voltage when the DC circuit breaker 12 is not connected in parallel with the resistance module 1, and when the test circuit is turned on, the control module 3 adjusts the resistance value of the resistance module 1 so that the current of the test circuit reaches the rated current of the DC circuit breaker 12. At the same time, the acquisition module 2 acquires the second voltage after the DC circuit breaker 12 is connected in parallel with the resistance module 1. Thus, the resistance module 1 with adjustable resistance value is used to control the current intensity and voltage distribution. By acquiring the voltage drop of the DC circuit breaker 12 and based on Ohm's law, the short-circuit current of the DC circuit breaker 12 can be calculated, so as to facilitate full verification using the short-circuit current of the DC circuit breaker 12 to ensure that the differential matching in the DC circuit is accurate, thereby ensuring the stable operation of the DC power supply system and preventing the spread of accidents and damage to equipment.

[0028] It should be noted that the DC circuit breaker 12 is a switch protection device used in a DC circuit to realize the opening and closing control of the circuit and the protection against faults such as overcurrent and short circuit. The working principle of the DC circuit breaker 12 is to control the contacts through the torque generated by the electromagnet, thereby cutting off the circuit.

[0029] When the test device of this embodiment performs the actions of resistance parallel connection and voltage acquisition of the DC circuit breaker 12, the DC circuit breaker 12 is still in operation in the DC power supply system. In this way, the upper and lower circuit breakers do not operate during the test, and the normal power supply of other feeder circuits is not affected. The impact on the DC system when the short-circuit current is large can be effectively avoided. The test risk is relatively small, and it is suitable for selective verification of DC circuit breakers 12 at different levels of the power system. Before the test, the DC circuit breaker 12 is in the disconnected state. When the DC circuit breaker 12 is closed, the test device performs the test action.

[0030] The first voltage is the normal operating voltage of the DC circuit breaker 12, and the second voltage is the voltage when the DC circuit breaker 12 is connected in parallel with the resistance module 1 and the current of the test circuit reaches the rated current of the DC circuit breaker 12. Since the currents before and after the DC circuit breaker 12 is connected in parallel with the resistance module 1 are the rated current of the DC circuit breaker 12, the rated current of the DC circuit breaker 12 is directly used in the calculation. Therefore, the short-circuit current of the DC circuit breaker 12 can be calculated using the rated current of the DC circuit breaker 12, the first voltage and the second voltage.

[0031] The resistance module 1 is used to be connected in parallel to the DC circuit breaker 12 to use resistance adjustment to control the current intensity and voltage distribution of the circuit (the current is within the range of ±10% of the rated current of the DC circuit breaker 12). The specific type of the resistance module 1 can be set according to actual needs and is not limited to this. For example, the resistance module 1 can be a programmable resistance box. The input end of the resistance module 1 is connected to the output end of the control module 3, and the resistance module 1 adjusts the resistance value under the control of the control module 3.

[0032] By adjusting the resistance value of the resistor module 1, the current of the test circuit reaches the rated current of the DC circuit breaker 12. However, in actual operation, it is difficult for the current of the test circuit to be completely consistent with the rated current of the DC circuit breaker 12. Therefore, a certain margin can be set. For example, the real-time current of the test circuit does not deviate from the preset rated current by more than 0.1%, that is, it can be considered that the current of the test circuit has reached the rated current of the DC circuit breaker 12.

[0033] The acquisition module 2 is used to acquire the first voltage and the second voltage of the DC circuit breaker 12, and the current of the test circuit. The specific type of the acquisition module 2 can be set according to actual needs, and there is no limitation on this. For example, the acquisition module 2 may include: a voltage acquisition unit and a current acquisition unit. The acquisition module 2 converts the acquired current and voltage signals into 4mA-20mA DC signals. The output end of the acquisition module 2 is connected to the input end of the control module 3, and the current and voltage signals acquired by the acquisition module 2 are sent to the control module 3.

[0034] The specific type of the control module 3 can be set according to actual needs and is not limited to this. For example, the control module 3 may include: a CPU board and an analog quantity acquisition board. The input end of the analog quantity acquisition board is connected to the output end of the acquisition module 2, and the output end of the analog quantity acquisition board is connected to the input end of the CPU board. The CPU board is used for receiving and sending data, executing complex computing tasks and controlling logic processing, etc.

[0035] In some embodiments, the control module 3 obtains the short-circuit current of the DC circuit breaker 12 based on a first formula, wherein the first formula is: Isc=U1×I / (U1-U2), Isc is the short-circuit current of the DC circuit breaker 12, I is the rated current of the DC circuit breaker 12, U1 is the first voltage, and U2 is the second voltage.

[0036] It can be understood that the control module 3 accurately calculates the short-circuit current of the DC circuit breaker 12 based on Ohm's law and according to the rated current of the DC circuit breaker 12, the first voltage before the DC circuit breaker 12 is connected in parallel with the resistance module 1, and the second voltage after the DC circuit breaker 12 is connected in parallel with the resistance module 1, so as to facilitate full verification using the short-circuit current of the DC circuit breaker 12 to ensure that the differential matching in the DC circuit is accurate.

[0037] It should be noted that I is the rated current of the DC circuit breaker 12 , which may also be referred to as the actual current of the DC circuit breaker 12 .

[0038] like Figure 1 and Figure 3As shown, in some embodiments, the test device also includes: a switch module 4, the switch module 4 is connected in series to the test circuit, and the input end of the switch module 4 is connected to the output end of the control module 3, and the control module 3 is used to control the switch module 4 to turn on or off the test circuit.

[0039] It can be understood that since the switch module 4 is connected in series to the test circuit and the input end of the switch module 4 is connected to the output end of the control module 3, the control module 3 can control the switch of the switch module 4 to realize the conduction or disconnection of the test circuit, thereby ensuring the stable collection of the first voltage and the second voltage, and further ensuring the accurate acquisition of the short-circuit current of the DC circuit breaker 12.

[0040] It should be noted that the switch module 4 is used for on-off control of the test circuit. The specific type of the switch module 4 can be set according to actual needs and is not limited to this. By way of example, the switch module 4 may include: multiple relays, multiple relays integrated on a circuit board, the control module 3 uses multiple relays to achieve on-off control of the test circuit, and the control module 3 uses multiple relays to achieve control of the resistance module 1 to adjust the size of the access resistance.

[0041] To cooperate with the switch module 4, the control module 3 may further include: a switch output card, the output end of the switch output card is connected to the input end of the switch module 4, and the input end of the switch output card is connected to the output end of the CPU card.

[0042] like Figure 1 and Figure 2 As shown, in some embodiments, the test device also includes: a touch display module 5, the output end of the touch display module 5 is connected to the input end of the control module 3, and the touch display module 5 is used to input the rated current signal of the DC circuit breaker 12 to the control module 3, so that the control module 3 adjusts the resistance value of the resistance module 1 according to the rated current of the DC circuit breaker 12, and the input end of the touch display module 5 is connected to the output end of the control module 3, and the control module 3 is used to input the short-circuit current signal of the DC circuit breaker 12 to the touch display module 5, so that the touch display module 5 displays the short-circuit current of the DC circuit breaker 12.

[0043] It can be understood that, since the output end of the touch display module 5 is connected to the input end of the control module 3, the touch display module 5 can input the rated current signal of the DC circuit breaker 12 to the control module 3, so that the control module 3 adjusts the resistance value of the resistor module 1 according to the rated current of the DC circuit breaker 12. At the same time, since the input end of the touch display module 5 is connected to the output end of the control module 3, the control module 3 can input the short-circuit current signal of the DC circuit breaker 12 to the touch display module 5, so that the touch display module 5 displays the short-circuit current of the DC circuit breaker 12. Therefore, the setting of the touch display module 5 makes the use of the test device more convenient.

[0044] It should be noted that the touch display module 5 is used for interaction between the control module 3 and the operator. Not only can the touch display module 5 be used to set the rated current of the DC circuit breaker 12 in the control module 3, but also the touch display module 5 can be used to display the test results such as the short-circuit current of the DC circuit breaker 12 calculated by the control module 3. The specific type of the touch display module 5 can be set according to actual needs, and there is no limitation to this. For example, the touch display module 5 can be a touch display screen. Among them, the communication end of the touch display module 5 is connected to the communication end of the CPU board.

[0045] The touch display module 5 and the control module 3 are connected via an RS485 communication serial port. The touch display module 5 can display the various states of the execution components of the control module 3 and can be operated to set test parameters. The modification of the signal state is returned to the control module 3 for corresponding execution.

[0046] like Figure 1 and Figure 2 As shown, in some embodiments, the test device also includes: a start-stop module 6, the output end of the start-stop module 6 is connected to the input end of the control module 3, and the start-stop module 6 is used to input a start-stop signal to the control module 3 so that the control module 3 performs a start-stop action according to the start-stop signal.

[0047] It can be understood that since the output end of the start-stop module 6 is connected to the input end of the control module 3, the start-stop module 6 can input a start-stop signal to the control module 3 so that the control module 3 performs a start-stop action according to the start-stop signal. Therefore, the setting of the start-stop module 6 makes the use of the test device more convenient.

[0048] It should be noted that the start-stop module 6 is used for the interaction between the control module 3 and the operator. The start-stop module 6 can be used to realize the start-stop control of the test device. The specific type of the start-stop module 6 can be set according to actual needs and is not limited to this. For example, the start-stop module 6 can be a handle switch.

[0049] To cooperate with the start-stop module 6, the control module 3 may further include: a switch quantity acquisition board, the input end of the switch quantity acquisition board is connected to the output end of the start-stop module 6, and the output end of the switch quantity acquisition board is connected to the input end of the CPU board.

[0050] like Figure 1 As shown, in some embodiments, the test device also includes: a power supply module 7, the power supply end of the power supply module 7 is connected to the power supply end of the external power supply, and the power supply end of the power supply module 7 is respectively connected to the power supply end of the resistance module 1 and the power supply end of the control module 3.

[0051] It can be understood that since the power supply end of the power supply module 7 is connected to the power supply end of the external power supply, and the power supply end of the power supply module 7 is respectively connected to the power supply end of the resistance module 1 and the power supply end of the control module 3, the power supply module 7 can use the electric energy of the external power supply to supply power to the resistance module 1 and the control module 3, thereby ensuring the stable operation of the test device.

[0052] It should be noted that the power module 7 is used for power conversion, transfer, etc. The specific type of the power module 7 can be set according to actual needs and is not limited to this. For example, the power module 7 can directly transmit the 220V AC power of the external power supply to the resistance module 1 and the control module 3.

[0053] Among them, to cooperate with the power module 7, the control module 3 can also include: a power board, the power supply end of the power board is connected to the power supply end of the power module 7, and the power supply end of the power board is respectively connected to the power supply end of the CPU board, the power supply end of the switch quantity acquisition board, the power supply end of the analog quantity acquisition board, the power supply end of the switch quantity output board and the power supply end of the touch display module 5. The power board outputs a DC 24V power supply after filtering, rectifying and inverting the AC 220V power supply.

[0054] like Figure 1 , Figure 2 and Figure 3 As shown, in some embodiments, the test device also includes: a test interface 8, a first wire 9 and a second wire 10, the test interface 8 and the resistance module 1 are connected in parallel, the first end of the first wire 9 is connected to the first end of the test interface 8, and the second end of the first wire 9 is connected to the first end of the DC circuit breaker 12, the first end of the second wire 10 is connected to the second end of the test interface 8, and the second end of the second wire 10 is connected to the second end of the DC circuit breaker 12.

[0055] It can be understood that, since the test interface 8 and the resistance module 1 are connected in parallel, and the first end of the first wire 9 is connected to the first end of the test interface 8, and the second end of the first wire 9 is connected to the first end of the DC circuit breaker 12, the first end of the resistance module 1 and the first end of the DC circuit breaker 12 can be connected by the first wire 9, and since the first end of the second wire 10 is connected to the second end of the test interface 8, and the second end of the second wire 10 is connected to the second end of the DC circuit breaker 12, the second end of the resistance module 1 and the second end of the DC circuit breaker 12 can be connected by the second wire 10. Thus, by using the cooperation of the first wire 9 and the second wire 10, the parallel wiring of the DC circuit breaker 12 and the resistance module 1 is realized, the operation is simple, and the use of the test device is more convenient.

[0056] It should be noted that the test interface 8 is used to be connected in parallel to the resistance module 1, and is used to plug the first end of the first wire 9 and the first end of the second wire 10. The specific type of the test interface 8 can be set according to actual needs and is not limited to this.

[0057] The first wire 9 is used for connection between the first end of the test interface 8 and the first end of the DC circuit breaker 12. The specific type of the first wire 9 can be set according to actual needs and is not limited to this. For example, the first end of the first wire 9 is designed to match the test interface 8 to achieve accurate and secure plug-in. The second end of the first wire 9 adopts a special dedicated pin connector, which can quickly and reliably make an electrical connection with the DC circuit breaker 12, thereby improving the efficiency and accuracy of the entire test system.

[0058] The second wire 10 is used for connection between the second end of the test interface 8 and the second end of the DC circuit breaker 12. The specific type of the second wire 10 can be set according to actual needs and is not limited to this. For example, the first end of the second wire 10 is designed to match the test interface 8 to achieve accurate and secure plug-in. The second end of the second wire 10 adopts a special dedicated pin connector, which can quickly and reliably make an electrical connection with the DC circuit breaker 12, thereby improving the efficiency and accuracy of the entire test system.

[0059] like Figure 1 and Figure 2 As shown, in some embodiments, the test device further includes: a test box 11, and the resistance module 1, the acquisition module 2 and the control module 3 are respectively arranged in the test box 11.

[0060] It can be understood that since the resistance module 1, the acquisition module 2 and the control module 3 are respectively arranged in the test box 11, the resistance module 1, the acquisition module 2 and the control module 3 can be centrally arranged and protected using the test device, making the test device more convenient to use and more stable in operation.

[0061] It should be noted that the test box 11 is used for the centralized arrangement and protection of the resistance module 1, the acquisition module 2 and the control module 3. The specific type of the test box 11 can be set according to actual needs and is not limited to this. For example, the test box 11 can be a closed box structure with an inspection door, and the resistance module 1, the acquisition module 2 and the control module 3 are encapsulated in the box.

[0062] In addition to the arrangement of the resistance module 1 , the acquisition module 2 and the control module 3 , the switch module 4 , the touch display module 5 , the start-stop module 6 , the power module 7 and the test interface 8 can be respectively arranged on the outer surface of the test box 11 .

[0063] In order to meet the wiring requirements of the test device, a terminal board can also be provided in the test box 11 to match the wires to connect various electrical devices, and the connecting wires are planned according to the preset circuit.

[0064] like Figure 4 As shown, the embodiment of the present disclosure further proposes a differential calibration method for a DC circuit breaker. The differential calibration method is based on a test device for a DC circuit breaker according to the embodiment of the present disclosure. The differential calibration method includes:

[0065] S1: Get the rated current of the lower DC circuit breaker;

[0066] S2: According to the rated current of the lower-level DC circuit breaker, the short-circuit current of the lower-level DC circuit breaker is obtained in the test device;

[0067] S3: Obtaining the instantaneous tripping current range of the upper DC circuit breaker, and comparing the short-circuit current of the lower DC circuit breaker with the instantaneous tripping current range of the upper DC circuit breaker;

[0068] S4: When the short-circuit current of the lower-level DC circuit breaker is within the instantaneous tripping current range of the upper-level DC circuit breaker, it is determined that there is an over-tripping risk between the upper-level DC circuit breaker and the lower-level DC circuit breaker.

[0069] It can be understood that the test device uses a resistor module with adjustable resistance to control the current intensity and voltage distribution. By collecting the voltage drop of the DC circuit breaker and based on Ohm's law, it can calculate the short-circuit current of the lower-level DC circuit breaker, so as to facilitate full verification using the short-circuit current of the lower-level DC circuit breaker and the instantaneous tripping current range of the upper-level DC circuit breaker to ensure that the differential coordination of the upper-level DC circuit breaker and the lower-level DC circuit breaker in the DC circuit is accurate, thereby ensuring the stable operation of the DC power supply system, preventing the spread of accidents and damage to equipment.

[0070] It should be noted that when the short-circuit current of the lower DC circuit breaker is not within the instantaneous tripping current range of the upper DC circuit breaker, it is determined that there is accurate step-difference coordination between the upper DC circuit breaker and the lower DC circuit breaker.

[0071] In some embodiments, the level difference verification method further includes:

[0072] Obtaining an instantaneous tripping current range of a lower-level DC circuit breaker, and comparing the short-circuit current of the lower-level DC circuit breaker with the instantaneous tripping current range of the lower-level DC circuit breaker;

[0073] When the short-circuit current of the lower-level DC circuit breaker is within the instantaneous tripping current range of the lower-level DC circuit breaker, it is determined that the lower-level DC circuit breaker operates reliably.

[0074] It can be understood that when the short-circuit current of the lower DC circuit breaker is within the instantaneous tripping current range of the lower DC circuit breaker, it indicates that the lower DC circuit breaker can perform reliable instantaneous action, thereby ensuring accurate grading between the upper DC circuit breaker and the lower DC circuit breaker.

[0075] Based on the differential calibration method of this embodiment, the following two groups of experiments are selected as examples:

[0076]

[0077] The test data are recorded as follows:

[0078] test U1 U2 I Isc Test 1 232.0V 228.7V 3.0A 210.9A Test 2 232.0V 226.9V 3.0A 136.5A

[0079] Therefore, the following experimental conclusions were drawn:

[0080] For test 1, the lower-level DC circuit breaker is a C-type DC miniature circuit breaker with a rated current of 3A and an instantaneous tripping current range of 21A-45A (7 times to 15 times the rated current). The short-circuit current obtained by the test device is 210.9A, which is greater than 45A. The lower-level DC circuit breaker can reliably and instantaneously operate; the upper-level DC circuit breaker is a C-type DC miniature circuit breaker with a rated current of 25A and an instantaneous tripping area of ​​175A-375A (7 times to 15 times the rated current). The short-circuit current of 210.9A of the lower-level DC circuit breaker is within the instantaneous tripping start area of ​​the upper-level DC circuit breaker (175A<210.9A<375A). Therefore, the lower-level DC circuit breaker can reliably and instantaneously operate, and the upper-level DC circuit breaker has a probability of instantaneous operation and a risk of over-tripping.

[0081] For test 2, the lower DC circuit breaker is a C-type DC miniature circuit breaker with a rated current of 3A and an instantaneous tripping current range of 21A-45A (7 to 15 times the rated current). The short-circuit current obtained by the test device is 136.5A, which is greater than 45A. The lower DC circuit breaker can reliably and instantaneously operate; the upper DC circuit breaker is a C-type DC miniature circuit breaker with a rated current of 25A and an instantaneous tripping range of 175A-375A (7 to 15 times the rated current). The short-circuit current of the lower DC circuit breaker is 136.5A, which is less than 175A. Therefore, the lower DC circuit breaker can reliably and instantaneously operate, the upper DC circuit breaker is in the overload protection action area, and the upper and lower DC circuit breakers meet the selectivity requirements.

[0082] It should be noted that, in the description of the present disclosure, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "plurality" is two or more.

[0083] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present disclosure includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present disclosure belong.

[0084] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0085] Although the embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A test device for a DC circuit breaker, characterized in that: include: A resistance module, wherein the resistance module and the DC circuit breaker are connected in parallel to form a test circuit; A collection module, wherein the collection end of the collection module is arranged on the test circuit, and the collection module is used to collect the current of the test circuit, and when the test circuit is disconnected, the collection module is used to collect the first voltage of the DC circuit breaker, and when the test circuit is connected, the collection module is used to collect the second voltage of the DC circuit breaker; A control module, wherein the control module is used to adjust the resistance value of the resistance module when the test circuit is turned on until the current of the test circuit reaches the rated current of the DC circuit breaker, and to obtain the short-circuit current of the DC circuit breaker according to the rated current of the DC circuit breaker, the first voltage and the second voltage.

2. The test device for DC circuit breaker according to claim 1, characterized in that: The control module obtains the short-circuit current of the DC circuit breaker based on a first formula; The first formula is: Isc=U1×I / (U1-U2), Isc is the short-circuit current of the DC circuit breaker, I is the rated current of the DC circuit breaker, U1 is the first voltage, and U2 is the second voltage.

3. The test device for DC circuit breaker according to claim 1, characterized in that: The test device also includes: A switch module is connected in series to the test loop, and an input end of the switch module is connected to an output end of the control module. The control module is used to control the switch module to turn on or off the test loop.

4. The test device for DC circuit breaker according to claim 1, characterized in that: The test device also includes: A touch display module, wherein the output end of the touch display module is connected to the input end of the control module, and the touch display module is used to input the rated current signal of the DC circuit breaker to the control module, so that the control module adjusts the resistance value of the resistance module according to the rated current of the DC circuit breaker, and the input end of the touch display module is connected to the output end of the control module, and the control module is used to input the short-circuit current signal of the DC circuit breaker to the touch display module, so that the touch display module displays the short-circuit current of the DC circuit breaker.

5. The test device for DC circuit breaker according to claim 1, characterized in that: The test device also includes: A start-stop module, wherein the output end of the start-stop module is connected to the input end of the control module, and the start-stop module is used to input a start-stop signal to the control module so that the control module performs a start-stop action according to the start-stop signal.

6. The test device for DC circuit breaker according to claim 1, characterized in that: The test device also includes: A power supply module, wherein the power supply end of the power supply module is connected to the power supply end of the external power supply, and the power supply end of the power supply module is respectively connected to the power supply end of the resistance module and the power supply end of the control module.

7. The test device for DC circuit breaker according to claim 1, characterized in that: The test device also includes: A test interface, the test interface and the resistance module are connected in parallel; A first wire, wherein a first end of the first wire is connected to a first end of the test interface, and a second end of the first wire is connected to a first end of the DC circuit breaker; A second wire, wherein a first end of the second wire is connected to a second end of the test interface, and a second end of the second wire is connected to a second end of the DC circuit breaker.

8. The DC circuit breaker test device according to claim 1, characterized in that: The test device also includes: A test box, wherein the resistance module, the acquisition module and the control module are respectively arranged in the test box.

9. A method for checking the level difference of a DC circuit breaker, characterized in that: The level difference verification method is based on the test device of the DC circuit breaker according to any one of claims 1 to 8, and the level difference verification method comprises: Obtain the rated current of the lower-level DC circuit breaker; According to the rated current of the lower-level DC circuit breaker, obtaining the short-circuit current of the lower-level DC circuit breaker in the test device; Acquiring an instantaneous tripping current range of an upper-level DC circuit breaker, and comparing the short-circuit current of the lower-level DC circuit breaker with the instantaneous tripping current range of the upper-level DC circuit breaker; When the short-circuit current of the lower-level DC circuit breaker is within the instantaneous tripping current range of the upper-level DC circuit breaker, it is determined that there is an over-tripping risk between the upper-level DC circuit breaker and the lower-level DC circuit breaker.

10. The DC circuit breaker level difference calibration method according to claim 9, characterized in that: The level difference verification method also includes: Acquiring an instantaneous tripping current range of the lower-level DC circuit breaker, and comparing the short-circuit current of the lower-level DC circuit breaker with the instantaneous tripping current range of the lower-level DC circuit breaker; When the short-circuit current of the lower-level DC circuit breaker is within the instantaneous tripping current range of the lower-level DC circuit breaker, it is determined that the lower-level DC circuit breaker operates reliably.

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