Test device for opening and closing time of double-ended grounded circuit breaker based on coupled high-frequency signal

Abstract

This invention provides a device and method for testing the opening and closing time of a double-grounded circuit breaker based on coupled high-frequency signals, relating to the field of power equipment testing technology. In this invention, a high-frequency measurement signal is coupled into the fluid-passing circuit via a high-frequency signal source. A DC power supply provides opening and closing pulse signals to the circuit breaker's opening and closing action control terminals. A ground wire is nested within a current transformer, which converts the acquired measurement signals and opening / closing pulses into multiple digital signals via a data acquisition card, and then transmits them to the host computer via a high-pass filter. Changes in the circuit signal reflect the circuit breaker's opening and closing status. The host computer analyzes the acquired measurement signals to calculate the circuit breaker's opening and closing time. This method can accurately measure the opening and closing time of a circuit breaker even when both ends are grounded, significantly reducing the labor intensity and working time of circuit breaker maintenance personnel while ensuring their safety.

Description

Technical Field

[0001] This invention relates to the field of power equipment testing technology, specifically to a device for testing the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals and its usage method. Background Technology

[0002] With the rapid development of modern power networks, 500kV substations, with their advantages of high transmission capacity and long transmission distance, have become an important component of the main power grid. 500kV high-voltage circuit breakers are crucial electrical equipment within substations, and their reliability directly impacts the stability of the entire power grid. Therefore, overhauling 500kV circuit breakers to ensure their normal operation is of great significance. The opening and closing times of high-voltage circuit breakers are important standards for evaluating their mechanical characteristics and three-phase synchronous performance. Generally, as the service life of a circuit breaker increases, its mechanical characteristics decline, and its opening and closing times become longer. Since high-voltage circuit breakers bear the dual responsibility of protecting and controlling other power equipment in the system, changes in their opening and closing times can significantly affect the safe and stable operation of the system. Therefore, accurate measurement of the opening and closing times of high-voltage circuit breakers is extremely important. Currently, the testing of the time characteristics of high-voltage circuit breakers generally involves first removing the grounding conductor on one side of the circuit breaker and suspending test leads at both ends. Then, an excitation is applied to the circuit formed by the circuit breaker and test leads using a switch tester. The opening and closing times of the circuit breaker are reconstructed by collecting the on / off times of the circuit response.

[0003] Traditional testing devices need to be connected in series in the circuit breaker circuit. However, some combined circuit breakers do not have lead-out points on both sides, requiring the busbar to be de-energized to conduct tests through adjacent outgoing line intervals, which is complex. Furthermore, workers face the risk of induced electric shock when removing the grounding wire, posing a safety hazard. On the other hand, suspending test leads often requires the use of insulated tie rods, which carries the risk of the rod falling and touching adjacent live parts. This is especially true for 500kV circuit breakers, where the tie rods are long, heavy, and pose high operational risks, high labor intensity, and low work efficiency. This is a significant factor affecting the efficiency and occupational safety of routine maintenance work on 500kV circuit breakers. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a device for testing the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals and its usage method, solving the technical problems of complex operation and potential safety hazards.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A device for testing the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals includes a circuit breaker, conductors, grounding wires, grounding grid, DC power supply, current transformer, high-frequency signal source, coupling device, data acquisition card, high-pass filter, and host computer.

[0009] The circuit breaker, conductors, grounding wires at both ends of the circuit breaker, and grounding grid constitute the circuit breaker fluid circuit; the high-frequency signal source is coupled to the circuit breaker fluid circuit via a coupling device; the current transformer is nested on the grounding wire at the end of the circuit breaker away from the coupling device, and is connected to the host computer via the data acquisition card and high-pass filter.

[0010] The DC power supply is used to send circuit breaker opening and closing signals, and triggers the circuit breaker to perform opening and closing actions through the circuit breaker's opening and closing action control terminal;

[0011] The host is used to trigger the data acquisition card to acquire the current signal of the circuit breaker's fluid flow circuit through the current transformer after detecting the circuit breaker's opening and closing signal, and to filter the low-frequency signal through the high-pass filter; and to obtain the circuit breaker's opening and closing time based on the filtered circuit breaker opening and closing signal and current signal.

[0012] Preferably, the current transformer is a Rogowski coil with an active integrator; the signal generated by the high-frequency signal source is a frequency-adjustable signal; the coupling device is a voltage transformer with a core made of manganese-zinc ferrite material, the primary side connected to the high-frequency signal source, the secondary side being a ground wire, and the transformation ratio being adjustable; the high-pass filter is an active high-pass filter; and the host is a micro industrial control host.

[0013] Preferably, the host computer detects the circuit breaker opening and closing signals through a high-voltage differential probe, which is installed at the DC power supply.

[0014] Preferably, the host includes:

[0015] The receiving module is used by the host to receive the filtered circuit breaker opening and closing signals and current signals.

[0016] The module is used to use time-frequency conversion to transform the filtered opening and closing pulse signals and current signals into the frequency domain, find the frequency change points of the two, and determine the opening and closing action points and the contact / disengagement points of the moving and stationary contacts.

[0017] The plotting module is used to plot a time curve based on the frequency domain transformation of the filtered circuit breaker opening and closing signals and current signals, combined with the waveforms of both in the time domain.

[0018] The acquisition module is used to acquire the circuit breaker opening and closing time based on the time curve, combined with the opening and closing action points and the contact / disengagement points of the moving and stationary contacts.

[0019] A method for using a double-ended grounding circuit breaker opening and closing time testing device based on coupled high-frequency signals includes:

[0020] S1, Test wiring;

[0021] Construct a test device for the opening and closing time of a double-ended grounded circuit breaker as described above.

[0022] S2, Inject measurement signal;

[0023] Based on the accuracy of the opening and closing time test, adjust the high-frequency measurement frequency output by the high-frequency signal source and the step size of the signal time-frequency characteristic analysis algorithm in the host, turn on the high-frequency signal source, and inject a high-frequency measurement signal into the fluid circuit of the circuit breaker through the coupler;

[0024] S3, Signal Acquisition;

[0025] After the host detects the circuit breaker opening and closing signal, it triggers the data acquisition card to collect the current signal of the circuit breaker's fluid-carrying circuit through the current transformer, and then filters the low-frequency signal through the high-pass filter.

[0026] S4. Data analysis; including:

[0027] S41. The host receives the filtered circuit breaker opening and closing signals and current signals;

[0028] S42. Using time-frequency conversion, the filtered opening and closing pulse signals and current signals are converted to the frequency domain, and the frequency abrupt change points of the two are found to determine the opening and closing action points and the contact / disengagement points of the moving and stationary contacts.

[0029] S43. Based on the frequency domain transformation of the filtered circuit breaker opening and closing signals and current signals into the time domain, and combining the waveforms of both in the time domain, draw a time curve.

[0030] S44. Based on the time curve, and in conjunction with the opening and closing action points and the contact / disengagement points of the moving and stationary contacts, obtain the opening and closing time of the circuit breaker.

[0031] Preferably, in step S1, the current transformer is selected as a Rogowski coil with an active integrator; the signal generated by the high-frequency signal source is a frequency-adjustable signal; the coupling device is a voltage transformer with a core made of manganese-zinc ferrite material, the primary side connected to the high-frequency signal source, the secondary side being a ground wire, and the transformation ratio being adjustable; the high-pass filter is an active high-pass filter; and the host is a micro industrial control host.

[0032] Preferably, adjusting the high-frequency measurement frequency according to the test accuracy in S2 specifically refers to:

[0033] The frequency of the high-frequency measurement signal is set to 10kHz~100kHz, corresponding to a test accuracy of 0.1ms~0.01ms;

[0034] The step size determination method for the signal time-frequency feature analysis algorithm is as follows, if the test accuracy is... The segment length of the high-frequency measurement signal in the time domain is The number of segments is ;but:

[0035]

[0036] in, This refers to the data acquisition frequency of the data acquisition card; The total length of the high-frequency measurement signal; using As the step size of the signal time-frequency feature analysis algorithm.

[0037] Preferably, a high-voltage differential probe is introduced in S3 and installed at the DC power supply, and the host detects the circuit breaker opening and closing signals through the high-voltage differential probe.

[0038] Preferably, in S44:

[0039] When measuring the closing time, locate the closing action point on the time curve and record it as t1; locate the contact point of the moving and stationary contacts and record it as t2; obtain the closing action time of the circuit breaker t = t2 - t1;

[0040] When measuring the tripping time, locate the tripping action point on the time curve and record it as t3; locate the point where the moving and stationary contacts separate and record it as t4; obtain the circuit breaker's closing action time t' = t4 - t3.

[0041] (III) Beneficial Effects

[0042] This invention provides a device for testing the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals, and its method of use. Compared with the prior art, it has the following advantages:

[0043] In this invention, a high-frequency measurement signal is coupled into the fluid-passing circuit via a high-frequency signal source. A DC power supply provides opening and closing pulse signals to the circuit breaker's opening and closing action control terminals. A ground wire is nested within a current transformer, which converts the acquired measurement signals and opening / closing pulses into multiple digital signals via a data acquisition card, and then transmits them to the host computer via a high-pass filter. Changes in the circuit signal reflect the circuit breaker's opening and closing status, and the host computer analyzes the acquired measurement signals to calculate the circuit breaker's opening and closing time. This method can accurately measure the circuit breaker's opening and closing time even when both ends are grounded, significantly reducing the labor intensity and working time of circuit breaker maintenance personnel while ensuring their safety. Attached Figure Description

[0044] 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.

[0045] Figure 1 A schematic diagram of the fluid-carrying circuit of a circuit breaker provided in an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the structure of a double-ended grounding circuit breaker opening and closing time testing device based on coupled high-frequency signals, provided for an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of a coupler provided for an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This application provides a test device and method for testing the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals. This solves the technical problems of complex operation and safety hazards, and makes up for the shortcomings of traditional test methods. With simple operation, the opening and closing time of the circuit breaker can be accurately measured without removing the ground wire.

[0050] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0051] The double-ended grounding circuit breaker opening and closing time testing device provided in this embodiment of the invention includes a circuit breaker, conductors, grounding wires, grounding grid, DC power supply, current transformer, high-frequency signal source, coupling device, data acquisition card, high-pass filter and host.

[0052] Among them, such as Figure 1As shown, in the state of double-terminal grounding of the circuit breaker, the circuit breaker, conductors, grounding wires at both ends of the circuit breaker, and grounding grid constitute the circuit breaker fluid-carrying circuit; the high-frequency signal source is coupled to the circuit breaker fluid-carrying circuit via a coupling device, and the current transformer is nested on the grounding wire at the end of the circuit breaker away from the coupling device, and connected to the host via the data acquisition card and high-pass filter.

[0053] Specifically, a high-frequency measurement signal is coupled into the fluid-passing circuit via a high-frequency signal source. A DC power supply provides opening and closing pulse signals to the circuit breaker's control terminals. A ground wire is nested within a current transformer, which converts the acquired measurement signals and opening / closing pulses into multiple digital signals via a data acquisition card, and then transmits them to the host computer via a high-pass filter. Changes in the circuit signal reflect the circuit breaker's opening status, and the host computer analyzes the acquired measurement signals to calculate the circuit breaker's opening and closing times. This method can accurately measure the circuit breaker's opening and closing times even with both ends grounded, significantly reducing the workload and working time for circuit breaker maintenance personnel while ensuring their safety.

[0054] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0055] Example 1:

[0056] like Figure 2 As shown, this embodiment of the invention provides a test device for the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals, including a circuit breaker, conductors, grounding wires, grounding grid, DC power supply, current transformer, high-frequency signal source, coupling device, data acquisition card, high-pass filter, and host.

[0057] The circuit breaker, conductors, grounding wires at both ends of the circuit breaker, and grounding grid constitute the circuit breaker's fluid-carrying circuit, ensuring the safe and stable operation of the circuit breaker (by grounding wires, unsafe charges or leakage currents generated by the circuit breaker due to various reasons are conducted to the grounding grid). The high-frequency signal source is coupled to the circuit breaker's fluid-carrying circuit via a coupling device. The current transformer is nested on the grounding wire at the end of the circuit breaker furthest from the coupling device and connected to the host computer via the data acquisition card and high-pass filter.

[0058] The DC power supply is used to send circuit breaker opening and closing signals, which trigger the circuit breaker to perform opening and closing actions via the circuit breaker's opening and closing action control terminals. It is important to note that the amplitude of the circuit breaker opening and closing action signal must be determined before measurement begins, and the output voltage of the DC power supply and the trigger pulse size of the data acquisition card should be set accordingly.

[0059] The current transformer is a Rogowski coil with an active integrator; the Rogowski coil is nested in the grounding wire and connected to the data acquisition card through the integrator.

[0060] The signal generated by the high-frequency signal source is a frequency-adjustable signal with a frequency range of 10kHz-100kHz.

[0061] like Figure 3 As shown, the coupling device is a voltage transformer with a core made of manganese-zinc ferrite material. The primary side is connected to a high-frequency signal source, and the secondary side is grounded. The turns ratio is adjustable. It is important to note that to prevent high-frequency signals from being suppressed, the turns ratio of the transformer is calculated by comparing the interference current in the circuit breaker loop with the impedance parameters of the loop. This makes it easier to measure and observe high-frequency measurement signals in the loop.

[0062] The high-pass filter is used to filter low-frequency interference signals induced in the circuit breaker circuit by electromagnetic fields within the substation. Its passband is designed according to the selected high-frequency power supply frequency, and it has good filtering performance for low-frequency signals, primarily power frequency. For example, an active high-pass filter with a passband frequency of 10kHz is specifically selected.

[0063] The host is a small, lightweight micro industrial control host. Upon detecting a circuit breaker opening / closing signal, the host triggers the data acquisition card to acquire the current signal of the circuit breaker's fluid-carrying circuit via a current transformer, and filters the low-frequency signal through a high-pass filter; and obtains the circuit breaker opening / closing time based on the filtered circuit breaker opening / closing signal and current signal.

[0064] In an optional embodiment, the host computer detects the circuit breaker's opening and closing signals via a high-voltage differential probe installed at the DC power supply. The opening and closing action signals emitted by the adjustable DC power supply are acquired by the high-voltage probe, converted into digital signals by a data acquisition card, and used as the start time of the circuit breaker's opening and closing action.

[0065] In an optional embodiment, the host includes:

[0066] The receiving module is used by the host to receive the filtered circuit breaker opening and closing signals and current signals.

[0067] The module is used to use time-frequency conversion to transform the filtered opening and closing pulse signals and current signals into the frequency domain, find the frequency change points of the two, and determine the opening and closing action points and the contact / disengagement points of the moving and stationary contacts.

[0068] The plotting module is used to plot a time curve based on the frequency domain transformation of the filtered circuit breaker opening and closing signals and current signals, combined with the waveforms of both in the time domain.

[0069] The acquisition module is used to acquire the circuit breaker opening and closing time based on the time curve, combined with the opening and closing action points and the contact / disengagement points of the moving and stationary contacts.

[0070] In an alternative embodiment, such as Figure 2 As shown in the figure, the double-ended grounding circuit breaker opening and closing time testing device provided in this embodiment of the invention may further include an isolating switch. Before the test begins, the isolating switch is in the open state; it is closed before the high-frequency signal source couples into the circuit breaker's fluid-carrying circuit; during the test, the isolating switch is in the closed state; after the experiment ends, the isolating switch is first opened, and then the high-frequency signal generator is turned off to ensure that no current flows through the circuit, thus ensuring the overall safety of the experiment.

[0071] Example 2:

[0072] This invention provides a method for using a double-ended grounding circuit breaker opening and closing time testing device based on coupled high-frequency signals, including:

[0073] S1, Test wiring;

[0074] Construct a test device for the opening and closing time of a double-ended grounding circuit breaker as described in Example 1;

[0075] S2, Inject measurement signal;

[0076] Based on the accuracy of the opening and closing time test, adjust the high-frequency measurement frequency output by the high-frequency signal source and the step size of the signal time-frequency characteristic analysis algorithm in the host, turn on the high-frequency signal source, and inject a high-frequency measurement signal into the fluid circuit of the circuit breaker through the coupler.

[0077] Specifically, adjusting the high-frequency measurement frequency according to the test accuracy refers to:

[0078] The frequency of the high-frequency measurement signal is set to 10kHz~100kHz, corresponding to a test accuracy of 0.1ms~0.01ms;

[0079] The step size determination method for the signal time-frequency feature analysis algorithm is as follows, if the test accuracy is... The segment length of the high-frequency measurement signal in the time domain is The number of segments is ;but:

[0080]

[0081] in, This refers to the data acquisition frequency of the data acquisition card; The total length of the high-frequency measurement signal; using As the step size of the signal time-frequency feature analysis algorithm.

[0082] S3, Signal Acquisition;

[0083] After detecting the circuit breaker opening and closing signal, the host triggers the data acquisition card to collect the current signal of the circuit breaker's fluid flow circuit through the current transformer, and then filters the low-frequency signal through the high-pass filter.

[0084] In this step, a high-voltage differential probe is introduced and installed at the DC power supply. The host unit detects the circuit breaker opening and closing signals through the high-voltage differential probe.

[0085] S4. Data analysis; including:

[0086] S41. The host receives the filtered circuit breaker opening and closing signals and current signals;

[0087] S42. Using time-frequency conversion, the filtered opening and closing pulse signals and current signals are converted to the frequency domain, and the frequency abrupt change points of the two are found to determine the opening and closing action points and the contact / disengagement points of the moving and stationary contacts.

[0088] S43. Based on the frequency domain transformation of the filtered circuit breaker opening and closing signals and current signals into the time domain, and combining the waveforms of both in the time domain, draw a time curve.

[0089] S44. Based on the time curve, and in conjunction with the opening and closing action points and the contact / disengagement points of the moving and stationary contacts, obtain the opening and closing time of the circuit breaker. Specifically:

[0090] When measuring the closing time, locate the closing action point on the time curve and record it as t1; locate the contact point of the moving and stationary contacts (i.e., the moment when the current signal changes abruptly from small to large) and record it as t2; obtain the closing action time of the circuit breaker t = t2 - t1.

[0091] When measuring the tripping time, locate the tripping action point on the time curve and record it as t3; locate the point where the moving and stationary contacts separate (i.e., the moment when the current signal changes abruptly from large to small) and record it as t4; obtain the circuit breaker's closing action time t' = t4 - t3.

[0092] In summary, compared with existing technologies, it has the following beneficial effects:

[0093] This invention enables precise measurement of the opening and closing times of a circuit breaker when both ends are grounded, overcoming the drawback of requiring the removal of one ground wire and suspension of test leads during current open-type circuit breaker characteristic testing. It significantly reduces the labor intensity and working time of circuit breaker maintenance personnel while ensuring their safety.

[0094] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0095] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for testing the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals, characterized in that, It includes circuit breakers, conductors, grounding wires, grounding grids, DC power supplies, current transformers, high-frequency signal sources, coupling devices, data acquisition cards, high-pass filters, and the host computer; The circuit breaker, conductors, grounding wires at both ends of the circuit breaker, and grounding grid constitute the circuit breaker fluid circuit; the high-frequency signal source is coupled to the circuit breaker fluid circuit via a coupling device; the current transformer is nested on the grounding wire at the end of the circuit breaker away from the coupling device, and is connected to the host computer via the data acquisition card and high-pass filter. The DC power supply is used to send circuit breaker opening and closing signals, and triggers the circuit breaker to perform opening and closing actions through the circuit breaker's opening and closing action control terminal; The host is used to trigger the data acquisition card to acquire the current signal of the circuit breaker's fluid-carrying circuit through the current transformer after detecting the circuit breaker's opening and closing signal, and to filter the low-frequency signal through the high-pass filter; and to obtain the circuit breaker's opening and closing time based on the filtered circuit breaker opening and closing signal and current signal. The host includes: The receiving module is used by the host to receive the filtered circuit breaker opening and closing signals and current signals. The module is used to use time-frequency conversion to transform the filtered opening and closing pulse signals and current signals into the frequency domain, find the frequency change points of the two, and determine the opening and closing action points and the contact / disengagement points of the moving and stationary contacts. The plotting module is used to plot a time curve based on the frequency domain transformation of the filtered circuit breaker opening and closing signals and current signals, combined with the waveforms of both in the time domain. The acquisition module is used to acquire the circuit breaker opening and closing time based on the time curve, combined with the opening and closing action points and the contact / disengagement points of the moving and stationary contacts.

2. The double-ended grounding circuit breaker opening and closing time testing device as described in claim 1, characterized in that, The current transformer is a Rogowski coil with an active integrator; the signal generated by the high-frequency signal source is a frequency-adjustable signal; the coupling device is a voltage transformer with a core made of manganese-zinc ferrite material, the primary side connected to the high-frequency signal source, the secondary side being a ground wire, and the transformation ratio being adjustable; the high-pass filter is an active high-pass filter; the host is a micro industrial control host.

3. The double-ended grounding circuit breaker opening and closing time testing device as described in claim 1, characterized in that, The host computer detects the circuit breaker opening and closing signals through a high-voltage differential probe, which is installed at the DC power supply.

4. A method for using a testing device for the opening and closing time of a double-ended grounded circuit breaker based on coupled high-frequency signals, characterized in that, include: S1, Test wiring; Construct the opening and closing time test device for a double-ended grounding circuit breaker as described in claim 1; S2, Inject measurement signal; Based on the accuracy of the opening and closing time test, adjust the high-frequency measurement frequency output by the high-frequency signal source and the step size of the signal time-frequency characteristic analysis algorithm in the host, turn on the high-frequency signal source, and inject a high-frequency measurement signal into the fluid circuit of the circuit breaker through the coupler; S3, Signal Acquisition; After the host detects the circuit breaker opening and closing signal, it triggers the data acquisition card to collect the current signal of the circuit breaker's fluid-carrying circuit through the current transformer, and then filters the low-frequency signal through the high-pass filter. S4. Data analysis; including: S41. The host receives the filtered circuit breaker opening and closing signals and current signals; S42. Using time-frequency conversion, the filtered opening and closing pulse signals and current signals are converted to the frequency domain, and the frequency abrupt change points of the two are found to determine the opening and closing action points and the contact / disengagement points of the moving and stationary contacts. S43. Based on the frequency domain transformation of the filtered circuit breaker opening and closing signals and current signals into the time domain, and combining the waveforms of both in the time domain, draw a time curve. S44. Based on the time curve, and in conjunction with the opening and closing action points and the contact / disengagement points of the moving and stationary contacts, obtain the opening and closing time of the circuit breaker.

5. The method of use as described in claim 4, characterized in that, In S1, the current transformer is selected as a Rogowski coil with an active integrator; the signal generated by the high-frequency signal source is a frequency-adjustable signal; the coupling device is a voltage transformer with a core made of manganese-zinc ferrite material, the primary side connected to the high-frequency signal source, the secondary side being a ground wire, and the transformation ratio being adjustable; the high-pass filter is an active high-pass filter; and the host is a micro industrial control host.

6. The method of use as described in claim 4, characterized in that, In S2, adjusting the high-frequency measurement frequency according to the test accuracy specifically refers to: The high-frequency measurement frequency is set to 10kHz~100kHz, corresponding to a test accuracy of 0.1ms~0.01ms; The step size determination method for the signal time-frequency feature analysis algorithm is as follows, if the test accuracy is... The segment length of the high-frequency measurement signal in the time domain is The number of segments is ;but: in, This refers to the data acquisition frequency of the data acquisition card; The total length of the high-frequency measurement signal; using As the step size of the signal time-frequency feature analysis algorithm.

7. The method of use as described in claim 4, characterized in that, A high-voltage differential probe is introduced into S3 and installed at the DC power supply. The host detects the circuit breaker opening and closing signals through the high-voltage differential probe.

8. The method of use as described in claim 4, characterized in that, In S44: When measuring the closing time, locate the closing action point on the time curve and record it as t1; locate the contact point of the moving and stationary contacts and record it as t2; obtain the closing action time of the circuit breaker t = t2 - t1; When measuring the tripping time, locate the tripping action point on the time curve and record it as t3; locate the point where the moving and stationary contacts separate and record it as t4; obtain the circuit breaker's closing action time t' = t4 - t3.

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