High Current Synthesis Test System and Method for Low-Voltage Electrical Products

Abstract

The application provides a low-voltage electrical product large-current synthesis test system and method, which comprises: a current source system comprising a first switching valve connected in series with a low-voltage electrical product, a first loop inductor, a first charging capacitor, a first charging system connected in parallel with the first charging capacitor, a first discharging component, a first loop voltage measuring device and a first grounding switch; a voltage source system comprising a second loop inductor connected in series with the low-voltage electrical product, a second switching valve, a second charging capacitor, a second charging system connected in parallel with the second charging capacitor, a second discharging component, a second loop voltage measuring device and a second grounding switch; the first switching valve and the second switching valve are reverse-parallel thyristor valves; the current source system, the voltage source system and a third loop current measuring device are grounded through a common point. The application can perform a low-voltage electrical product large-current synthesis test with low risk.

Description

Technical Field

[0001] This invention relates to the field of power systems, and in particular to a high-current synthesis test system and method for low-voltage electrical products. Background Technology

[0002] According to the standards for low-voltage electrical products, short-circuit current testing is an important part of the testing process, primarily aimed at verifying that the breaking characteristics of low-voltage products are consistent with their dynamic and thermal stability. Technically, the application of synthetic circuits for breaking high-voltage circuit breakers is quite mature. A high-current test circuit based on the LC oscillation principle is a feasible solution for short-circuit testing of low-voltage electrical products. In existing technology, the high-current closing switch in the circuit typically uses one three-pole vacuum switch, while the opening switch uses two six-pole vacuum switches connected in parallel. However, due to deviations in the timing of the circuit breaker's closing and opening controls and the dispersion of the operating mechanisms, there is a risk of burn-out and welding of one of the vacuum switch contacts. Furthermore, this technology can only be used to test the short-circuit high-current characteristics of the sample, resulting in a limited functionality. Summary of the Invention

[0003] This invention provides a high-current synthesis test system for low-voltage electrical products, capable of performing high-current synthesis tests on low-voltage electrical products. It uses a switching valve instead of a conventional auxiliary circuit breaker, effectively avoiding the risks of timing deviations in the closing and opening control of circuit breakers, the dispersion of operating mechanisms, and the risk of burn-out and welding of certain contacts in vacuum switches. The system includes:

[0004] A current source system, a voltage source system, and a third-circuit voltage measuring device are connected in parallel with the low-voltage electrical products, respectively, and a third-circuit current measuring device is connected in series with the low-voltage electrical products, wherein,

[0005] The current source system includes a first switching valve connected in series with a low-voltage electrical product, a first circuit inductor, a first charging capacitor, a first charging system connected in parallel with the first charging capacitor, a first discharging component, a first circuit voltage measuring device, and a first grounding switch;

[0006] The voltage source system includes a second circuit inductor connected in series with the low-voltage electrical products, a second switching valve, a second charging capacitor, a second charging system connected in parallel with the second charging capacitor, a second discharging component, a second circuit voltage measuring device, and a second grounding switch;

[0007] The first and second switching valves are reverse parallel thyristor valves;

[0008] The current source system, voltage source system, and third-circuit current measuring device are grounded at a common point.

[0009] This invention proposes a method for conducting high-current synthesis tests on low-voltage electrical products. Applied to the aforementioned high-current synthesis test system for low-voltage electrical products, this method enables high-current synthesis tests on low-voltage electrical products. By using a switching valve instead of a conventional auxiliary circuit breaker, it effectively avoids the risks of timing deviations in the closing and opening control of the circuit breaker, the dispersion of operating mechanisms, and the risk of burn-out and welding of a certain pole contact of a vacuum switch. The method includes:

[0010] Disconnect the first discharge component, the second discharge component, the first grounding switch, the second grounding switch, the first switching valve, and the second switching valve;

[0011] Connect the low-voltage electrical products to the high-current synthesis test system for low-voltage electrical products, and keep them disconnected;

[0012] Simultaneously connected to both the first and second charging systems;

[0013] The voltage across the first charging capacitor is measured using the first circuit voltage measuring device. Once the measured value of the first circuit voltage measuring device reaches the target test voltage for low-voltage electrical products, the first charging system is disconnected.

[0014] The voltage across the second charging capacitor is measured using the second circuit voltage measuring device. Once the measured value of the second circuit voltage measuring device reaches the target test voltage for low-voltage electrical products, the second charging system is disconnected.

[0015] When the low-voltage electrical product is closed, a conduction pulse is triggered on the first switching valve; the first charging capacitor oscillates and discharges after the conduction pulse begins, and an oscillating current is generated in the current source system circuit; after the oscillating current flows through the low-voltage electrical product, the low-voltage electrical product triggers short-circuit protection and disconnects automatically; when the oscillating current measured by the third circuit current measuring device crosses zero, a conduction pulse is triggered on the second switching valve, and the recovery voltage of the second charging capacitor is applied to both ends of the low-voltage electrical product;

[0016] The third circuit voltage measuring device is read in real time. After the measured value of the third circuit voltage measuring device reaches the target test voltage of the low-voltage electrical product, the first discharge component and the second discharge component are connected.

[0017] The voltage of the first circuit is read in real time, and the first grounding switch is closed after the measured value of the voltage of the first circuit reaches zero.

[0018] The second circuit voltage measuring device is read in real time. After the measured value of the second circuit voltage measuring device reaches zero, the second grounding switch is closed.

[0019] In this embodiment of the invention, the current source system includes a first switching valve, a first circuit inductor, a first charging capacitor, a first charging system, a first discharging component, a first circuit voltage measuring device, and a first grounding switch, all connected in series with the low-voltage electrical product. The voltage source system includes a second circuit inductor, a second switching valve, a second charging capacitor, a second charging system, a second discharging component, a second circuit voltage measuring device, and a second grounding switch, all connected in series with the low-voltage electrical product. The first switching valve and the second switching valve are reverse-parallel thyristor valves. The current source system, the voltage source system, and the third circuit voltage measuring device are all grounded. In the above process, a current source system is used to generate the large current required for the short-circuit breaking test of low-voltage electrical products, and a voltage source system is used to introduce a recovery voltage after the low-voltage electrical products break the short-circuit current, thereby realizing the large current synthesis test of low-voltage electrical products. Furthermore, since the first and second switching valves are reverse parallel thyristor valves, the risks of deviations in the closing and opening control of conventional circuit breakers, the dispersion of operating mechanisms, and the risk of burn-out and welding of a certain contact of a vacuum switch can be effectively avoided. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0021] Figure 1 This is a schematic diagram of a high-current synthesis test system for low-voltage electrical products in an embodiment of the present invention;

[0022] Figure 2 This is a flowchart of the high-current synthesis test method for low-voltage electrical products in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0024] In the description of this specification, the terms "comprising," "including," "having," and "containing" are open-ended terms, meaning that they include but are not limited to. The terms "an embodiment," "a specific embodiment," "some embodiments," and "for example," etc., refer to specific features, structures, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. The order of steps involved in the various embodiments is used to illustrate the implementation of this application, and the order of steps is not limited and can be adjusted appropriately as needed.

[0025] Figure 1 This is a schematic diagram of a high-current synthesis test system for low-voltage electrical products in an embodiment of the present invention. The high-current synthesis test system for low-voltage electrical products includes:

[0026] A current source system, a voltage source system, and a third-circuit voltage measuring device PT3 are connected in parallel with the low-voltage electrical product TO, respectively, and a third-circuit current measuring device CT3 is connected in series with the low-voltage electrical product.

[0027] The current source system includes a first switching valve connected in series with the low-voltage electrical product TO, a first circuit inductor, a first charging capacitor Ci, a first charging system connected in parallel with the first charging capacitor Ci, a first discharging component, a first circuit voltage measuring device PT1, and a first grounding switch K. E1 ;

[0028] The voltage source system includes a second-circuit inductor L connected in series with the low-voltage electrical product TO. S1 Second switching valve, second charging capacitor C S , respectively with the second charging capacitor C S The second charging system, the second discharging component, the second circuit voltage measuring device PT2, and the second grounding switch K are connected in parallel. E2 ;

[0029] The first and second switching valves are reverse parallel thyristor valves;

[0030] The current source system, voltage source system, and third circuit current measuring device CT3 are grounded through a common point O.

[0031] In the above embodiments, a current source system is used to generate the large current required for the short-circuit breaking test of low-voltage electrical products, and a voltage source system is used to introduce a recovery voltage after the low-voltage electrical products break the short-circuit current, thereby realizing the large current synthesis test of low-voltage electrical products. Furthermore, since the first and second switching valves are reverse parallel thyristor valves, the risks of deviations in the closing and opening control of conventional circuit breakers, the dispersion of operating mechanisms, and the risk of burn-out and welding of a certain contact of a vacuum switch can be effectively avoided.

[0032] The first switching valves are VO1 and VO2, and the second switching valves are V1 and V2. Low-voltage electrical products TO can be low-voltage equipment such as molded case circuit breakers, frame circuit breakers, dual power supplies, miniature switches, and equipment circuit breakers, and their states include open and closed states.

[0033] In one embodiment, the first charging system includes a first current source system switch K1, a second current source system switch K2, and a first power supply U1;

[0034] The first terminal of the first current source system switch K1 is connected to the first terminal of the first charging capacitor Ci;

[0035] The first terminal of the second current source system switch K2 is connected to the second terminal of the first charging capacitor Ci;

[0036] The first power supply U1 is connected to the second terminal of the first current source system switch K1 and the second terminal of the second current source system switch K2, respectively.

[0037] The second charging system includes a first voltage source system switch K3, a second voltage source system switch K4, and a second power supply U2;

[0038] The first terminal of the first voltage source system switch K3 is connected to the second charging capacitor C. S The first end is connected;

[0039] The first terminal of the second voltage source system switch K4 is connected to the second charging capacitor C. S The second end is connected;

[0040] The second power supply U2 is connected to the second terminal of the first voltage source system switch K3 and the second voltage source system switch K4, respectively.

[0041] For example, in one embodiment, the first charging capacitor is an adjustable capacitor Ci, and the first loop inductor is an adjustable inductor Li1. By adjusting different capacitor and inductor values, different large currents can be obtained under the same voltage, enabling experiments of various scales.

[0042] In one embodiment, the first discharge component includes a first discharge resistor Ri and a first connection switch K connected in series. R1 ;

[0043] The second discharge component includes a second discharge resistor R connected in series. S Second connection switch K R2 .

[0044] In one embodiment, the voltage source system further includes a frequency modulation circuit assembly connected in parallel with the low-voltage electrical product;

[0045] The frequency modulation circuit assembly includes a frequency modulation circuit resistor R1 and a frequency modulation circuit capacitor C1 connected in series. The frequency modulation circuit resistor R1 and the frequency modulation circuit capacitor C1 play a frequency modulation role and can be used to adjust the waveform of the recovery voltage.

[0046] In one embodiment, the frequency modulation circuit resistor R1 is an adjustable resistor, and the frequency modulation circuit capacitor C1 is an adjustable capacitor. Similarly, the adjustable resistor and adjustable capacitor allow for the generation of large currents of different magnitudes at the same voltage.

[0047] In one embodiment, the first charging system further includes a first loop current measuring device CT1, the first terminal of the first loop current measuring device CT1 being connected to the second terminal of the first charging capacitor Ci; the second terminal of the first loop current measuring device CT1 being grounded via a common point O.

[0048] The second charging system also includes a second circuit current measuring device CT2, the first terminal of which is connected to the second charging capacitor C. S The second terminal is connected; the second terminal of the second circuit current measuring device CT2 is grounded via common point O.

[0049] The function of the first circuit current measuring device CT1 and the second circuit current measuring device CT2 is to measure the current in their respective circuits.

[0050] In addition, the function of the third circuit current measuring device CT3 is to measure the oscillating current to determine whether it crosses zero. When the oscillating current measured by CT3 crosses zero, it triggers the second switching valve to turn on with a pulse. In addition, CT3 can measure the current in the circuit it is in.

[0051] This invention also proposes a method for high-current synthesis testing of low-voltage electrical products, which is applied to the aforementioned high-current synthesis testing system for low-voltage electrical products.

[0052] Figure 2 The flowchart of the high-current synthesis test method for low-voltage electrical products in this embodiment of the invention includes:

[0053] Step 201: Disconnect the first discharge component, the second discharge component, the first grounding switch, the second grounding switch, the first switching valve, and the second switching valve;

[0054] Specifically, disconnecting the first discharge component and the second discharge component means disconnecting the first connection switch K. R1 Second connection switch K R2 .

[0055] Step 202: Connect the low-voltage electrical products to the high-current synthesis test system for low-voltage electrical products and keep them disconnected;

[0056] Step 203: Simultaneously connect to the first charging system and the second charging system;

[0057] Specifically, closing the first current source system switch K1 and the second current source system switch K2, and closing the first voltage source system switch K3 and the second voltage source system switch K4, is for the purpose of charging the first charging capacitor and the second charging capacitor.

[0058] Step 204: Measure the voltage across the first charging capacitor using the first circuit voltage measuring device. Once the measured value of the first circuit voltage measuring device reaches the target test voltage for the low-voltage electrical product, disconnect the first charging system.

[0059] Specifically, disconnecting the first charging system means disconnecting the first current source system switch K1 and the second current source system switch K2.

[0060] Step 205: Measure the voltage across the second charging capacitor using the second circuit voltage measuring device. Once the measured value of the second circuit voltage measuring device reaches the target test voltage for the low-voltage electrical product, disconnect the second charging system.

[0061] Specifically, disconnecting the second charging system means disconnecting the first voltage source system switch K3 and the second voltage source system switch K4.

[0062] Step 206: Close the low-voltage electrical product and trigger the conduction pulse of the first switching valve; the first charging capacitor oscillates and discharges after the conduction pulse begins, and the current source system circuit generates an oscillating current; after the oscillating current flows through the low-voltage electrical product, the low-voltage electrical product triggers short-circuit protection and disconnects automatically; when the oscillating current measured by the third circuit current measuring device crosses zero, the second switching valve conduction pulse is triggered, and the recovery voltage of the second charging capacitor is applied to both ends of the low-voltage electrical product;

[0063] Step 207: Read the third circuit voltage measuring device in real time. After the measured value of the third circuit voltage measuring device reaches the target test voltage of the low-voltage electrical product, connect the first discharge component and the second discharge component.

[0064] Step 208: Read the voltage of the first circuit in real time. After the measured value of the voltage of the first circuit reaches zero, close the first grounding switch.

[0065] When the voltage measurement value of the first circuit reaches zero, it means that the first charging capacitor has finished discharging.

[0066] Step 209: Read the second circuit voltage measuring device in real time. After the measured value of the second circuit voltage measuring device reaches zero, close the second grounding switch.

[0067] When the voltage measurement value of the second circuit reaches zero, it means that the discharge of the second charging capacitor has ended.

[0068] Using the above system and method, the current source system can achieve an AC current peak value of 0–212 kA, a frequency of 10–100 Hz, and an equivalent DC current of 0–50 kA; the voltage source system can restore voltage. The functional adjustment allows for short-circuit current breaking tests and the application of recovery voltage to low-voltage electrical products, comprehensively verifying their short-circuit breaking performance. It features high output current, comprehensive testing functions, low construction difficulty, and strong versatility. Furthermore, compared to vacuum circuit breakers, the reverse-parallel thyristor valve used in this embodiment as the switching switch effectively avoids the risks of timing deviations in closing and opening control, the dispersion of operating mechanisms, and the risk of burnt-out contacts on certain poles of vacuum switches, all inherent in conventional circuit breakers. The system and method proposed in this embodiment can improve the performance testing capabilities of low-voltage electrical products, possessing valuable potential and economic benefits.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for synthetic testing of a low voltage electrical product for high current, characterized in that, The application is applied to a low-voltage electrical product large-current synthetic test system, the low-voltage electrical product large-current synthetic test system comprises a current source system, a voltage source system and a third loop voltage measuring device connected in parallel with the low-voltage electrical product respectively, and a third loop current measuring device connected in series with the low-voltage electrical product, wherein the current source system comprises a first switching valve, a first loop inductor, a first charging capacitor connected in series with the low-voltage electrical product respectively, a first charging system connected in parallel with the first charging capacitor respectively, a first discharge component, a first loop voltage measuring device and a first grounding switch; the voltage source system comprises a second loop inductor, a second switching valve, a second charging capacitor connected in series with the low-voltage electrical product respectively, a second charging system connected in parallel with the second charging capacitor respectively, a second discharge component, a second loop voltage measuring device and a second grounding switch; the first switching valve and the second switching valve are reverse-parallel thyristor valves; the current source system, the voltage source system and the third loop current measuring device are grounded through a common point; The method comprises: disconnecting the first discharge component, the second discharge component, the first grounding switch, the second grounding switch, the first switching valve and the second switching valve; connecting the low-voltage electrical product to the low-voltage electrical product large-current synthetic test system and keeping it in a disconnected state; simultaneously connecting the first charging system and the second charging system; measuring the voltage across the first charging capacitor by the first loop voltage measuring device, and disconnecting the first charging system when the measured value of the first loop voltage measuring device reaches the target test voltage of the low-voltage electrical product; measuring the voltage across the second charging capacitor by the second loop voltage measuring device, and disconnecting the second charging system when the measured value of the second loop voltage measuring device reaches the target test voltage of the low-voltage electrical product; closing the low-voltage electrical product, triggering the conduction pulse of the first switching valve; the first charging capacitor oscillates and discharges after the conduction pulse starts, and the current source system loop generates an oscillating current; after the oscillating current flows through the low-voltage electrical product, the low-voltage electrical product triggers a short-circuit protection and then self-disconnects; when the oscillating current measured by the third loop current measuring device is zero, a conduction pulse of the second switching valve is triggered, and the recovery voltage of the second charging capacitor is applied across the low-voltage electrical product; real-time reading of the third loop voltage measuring device, and connecting the first discharge component and the second discharge component when the measured value of the third loop voltage measuring device reaches the target test voltage of the low-voltage electrical product; real-time reading of the first loop voltage measuring device, and closing the first grounding switch when the measured value of the first loop voltage measuring device reaches zero; real-time reading of the second loop voltage measuring device, and closing the second grounding switch when the measured value of the second loop voltage measuring device reaches zero.

2. The method of claim 1, wherein, The first charging system comprises a first current source system switch, a second current source system switch and a first power supply; the first end of the first current source system switch is connected with the first end of the first charging capacitor; the first end of the second current source system switch is connected with the second end of the first charging capacitor; the first power supply is connected with the second end of the first current source system switch and the second end of the second current source system switch respectively. The second charging system comprises a first voltage source system switch, a second voltage source system switch and a second power supply; The first end of the first voltage source system switch is connected with the first end of the second charging capacitor; The first end of the second voltage source system switch is connected with the second end of the second charging capacitor; The second power supply is connected with the second end of the first voltage source system switch and the second end of the second voltage source system switch respectively.

3. The method of claim 1, wherein, The first discharging assembly comprises a first discharging resistor and a first connecting switch connected in series; The second discharging assembly comprises a second discharging resistor and a second connecting switch connected in series.

4. The method of claim 1, wherein, The voltage source system further comprises a frequency modulation loop assembly connected in parallel with the low-voltage electrical product; The frequency modulation loop assembly comprises a frequency modulation loop resistor and a frequency modulation loop capacitor connected in series.

5. The method of claim 4, wherein, The frequency modulation loop resistor is an adjustable resistor, and the frequency modulation loop capacitor is an adjustable capacitor.

6. The method of claim 1, wherein, The first charging system further comprises a first loop current measuring device, the first end of the first loop current measuring device being connected with the second end of the first charging capacitor; and the second end of the first loop current measuring device being grounded through a common point. The second charging system further comprises a second loop current measuring device, the first end of the second loop current measuring device being connected with the second end of the second charging capacitor; and the second end of the second loop current measuring device being grounded through a common point.

7. The method of claim 1, wherein, The first charging capacitor is an adjustable capacitor, and the first loop inductor is an adjustable inductor.

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