Circuit breaker opening and closing time measurement device based on DC component of interference current

Abstract

The present invention provides a circuit breaker opening and closing time measurement device based on the DC component of interference current and a method for using the same, and relates to the technical field of power equipment testing. In the present invention, a circuit breaker opening and closing pulse signal is applied; the interference current in the circuit when the circuit breaker is opening and closing is collected; the DC component is extracted from the interference current, and the time-frequency characteristic analysis of the DC component is performed; the time-frequency variation curve of the DC component is obtained, and the opening and closing moments are located by analyzing the curve to obtain the opening and closing time. The device is simple to operate, safe and reliable, does not require excessive manpower, material and financial resources, and does not require direct contact with the circuit breaker. The circuit breaker opening and closing time can be obtained, thereby improving the work efficiency of maintenance personnel and enhancing the reliability and safety of power operation.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment testing, and in particular to a circuit breaker opening and closing time measuring device based on a DC component of an interference current and a method for using the device. Background Art

[0002] A circuit breaker's opening and closing times are important criteria for evaluating its mechanical characteristics and three-phase synchronous performance. Generally speaking, as a circuit breaker's service life increases, its mechanical characteristics deteriorate, and its opening and closing times increase. High-voltage circuit breakers shoulder the dual tasks of protecting and controlling other electrical equipment in the system. Variations in their opening and closing times can significantly impact the safe and stable operation of the system. Therefore, accurately measuring the opening and closing times of high-voltage circuit breakers is crucial. Currently, testing the timing characteristics of high-voltage circuit breakers typically involves first removing the grounding conductor on one side of the circuit breaker and suspending test leads between two sections. A switch tester is then used to apply excitation to the circuit formed by the circuit breaker and test leads. The circuit breaker's opening and closing times are then reconstructed by recording the on and off moments of the circuit's response.

[0003] Traditional circuit breaker time characteristic testing typically uses the DC resistance method. A tester is connected in series with the circuit breaker circuit, providing a DC source to measure the circuit resistance and determine the circuit breaker's open / closed state. To prevent the influence of ground resistance on the measurement results, this method requires removing one end of the ground wire. Because the ground circuit resistance is relatively low, the parallel connection of the circuit breaker break and the ground resistance makes it difficult to discern the resistance change between open and closed states. However, some combination switchgear circuit breakers lack lead points at both ends, requiring the busbar to be shut down to conduct the test through adjacent lead-out intervals. This is complex and tedious, and reduces maintenance efficiency. Furthermore, due to electromagnetic induction between incoming and outgoing lines and the busbar, workers face the risk of electric shock (with induced voltages reaching thousands of volts) when removing the ground wire, posing a significant safety hazard. Furthermore, the test wire often requires the use of an insulated tie rod, which carries the risk of the rod falling and contacting adjacent live parts. Some scholars have now proposed coupling current into the line and calculating the circuit breaker opening and closing time by observing the changes in the coupling current. Although this method does not require direct contact, it is relatively expensive, requires more equipment, and the coupling current is also unstable.

[0004] The above measurement methods each have their own advantages and disadvantages. Basically, they can measure the opening and closing speed of the circuit breaker. However, due to different working modes, the opening and closing speed detection results of the same circuit breaker may be different. It is impossible to determine which method or equipment is more accurate. In addition, the detection is slow, the steps are cumbersome, and more equipment is required, which is a waste of manpower, material and financial resources. Summary of the Invention

[0005] (1) Technical problems solved

[0006] In response to the shortcomings of the existing technology, the present invention provides a circuit breaker opening and closing time measurement device based on the DC component of the interference current and a method of using the same, which solves the technical problems of slow detection, complicated steps, and the need for more equipment.

[0007] (2) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] A circuit breaker opening and closing time measuring device based on the DC component of interference current includes a circuit breaker, a conductor, a grounding wire, a grounding grid, a circuit breaker opening and closing action control terminal, an opening and closing pulse generator, a current transformer, a filter, an operational amplifier, an inductor circuit, a data acquisition card and a host;

[0010] The circuit breaker, the conductor, the connecting wires at both ends of the circuit breaker, and the ground grid constitute a circuit breaker fluid circuit; the current transformer is coupled to the circuit breaker fluid circuit;

[0011] The opening and closing pulse generator is used to send out the circuit breaker opening and closing signals, and trigger the circuit breaker to perform opening and closing actions through the circuit breaker opening and closing action control terminal;

[0012] The host is used to trigger the data acquisition card to collect the current signal of the circuit breaker fluid circuit through the current transformer after detecting the circuit breaker opening and closing signal, and sequentially filter out the power frequency current through the filter, amplify the signal through the operational amplifier, and filter out the AC component of the interference current through the inductor circuit to obtain the DC component; and is used to obtain the circuit breaker opening and closing time based on the circuit breaker opening and closing signal and the DC component.

[0013] Preferably, the opening and closing pulse generator is controlled by infrared remote control; the current transformer is a Rogowski coil with an active integrator; and the operational amplifier has an adjustable transformation ratio function.

[0014] Preferably, the host detects the circuit breaker opening and closing signals through a high-voltage differential probe, and the high-voltage differential probe is installed at the opening and closing pulse generator.

[0015] Preferably, the host includes:

[0016] A receiving module, used for receiving circuit breaker opening and closing signals, and DC components in the form of a table file;

[0017] A search module is used to find the mutation point of the circuit breaker opening and closing signals in the time domain and determine the opening and closing action points; and to open the DC component table file according to the set path, find the mutation point of the DC component in the time domain based on the detection threshold, and determine the contact point of the moving and static contacts;

[0018] A drawing module, configured to draw a time curve graph according to the waveform of the circuit breaker opening and closing signal and the DC component in the time domain;

[0019] The acquisition module is used to obtain the circuit breaker opening and closing time according to the time curve, combined with the opening and closing action point and the contact / disengagement point of the moving and static contacts.

[0020] A method for using a circuit breaker opening and closing time measuring device based on a DC component of an interference current includes:

[0021] S1, test wiring;

[0022] Constructing the circuit breaker opening and closing time measuring device as claimed in claim 1;

[0023] S2. Parameter adjustment; including:

[0024] Set the DC component data file path and the DC component data before and after mutation detection threshold; select the operational amplifier ratio according to the size of the electromagnetic interference

[0025] S3. Signal acquisition; including:

[0026] 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 fluid circuit through the current transformer, and sequentially filters the power frequency current through the filter, amplifies the signal through the operational amplifier, and filters the AC component of the interference current through the inductor circuit to obtain the DC component; the DC component is processed by the data acquisition card and uploaded to the host in the form of a table file;

[0027] S4. Data analysis; including:

[0028] S41, the host receives a circuit breaker opening and closing signal and a DC component in a table file format;

[0029] S42, finding a sudden change point in the time domain of the circuit breaker opening and closing signals to determine the opening and closing action points; and opening a table file of the DC component according to a set path, finding a sudden change point in the time domain of the DC component based on a detection threshold, and determining the contact / disengagement point of the moving and static contacts;

[0030] S43, drawing a time curve graph according to the waveform of the circuit breaker opening and closing signal and the DC component in the time domain;

[0031] S44. Obtain the circuit breaker opening and closing time according to the time curve, in combination with the opening and closing action points and the contact / disengagement points of the moving and static contacts.

[0032] Preferably, in S1, infrared remote control is used to control the opening and closing pulse generator; the current transformer is selected as a Rogowski coil with an active integrator; and an operational amplifier with an adjustable ratio function is selected.

[0033] Preferably, a high-voltage differential probe is introduced into S3 and installed at the opening and closing pulse generator, and the host detects the circuit breaker opening and closing signals through the high-voltage differential probe.

[0034] Preferably, in said S44:

[0035] When measuring the closing time, the closing action point is located on the time curve, recorded as t1; the contact point of the moving and static contacts is located, recorded as t2; and the closing action time of the circuit breaker is obtained as t=t2-t1;

[0036] When measuring the opening time, locate the opening action point on the time curve, record it as t3; locate the separation point of the moving and static contacts, record it as t4; and obtain the closing action time of the circuit breaker t'=t4-t3.

[0037] (3) Beneficial effects

[0038] The present invention provides a circuit breaker opening and closing time measurement device based on the DC component of interference current and a method for using the device. Compared with the prior art, the device has the following advantages:

[0039] In the present invention, a circuit breaker opening and closing pulse signal is applied; interference current in the circuit during the circuit breaker opening and closing is collected; a DC component is extracted from the interference current and a time-frequency characteristic analysis is performed on the DC component; a time-frequency variation curve of the DC component is obtained, and the opening and closing moments are located by analyzing the curve to obtain the opening and closing times. The method is simple to operate, safe, and reliable, and does not require excessive manpower, material, or financial resources, nor does it require direct contact with the circuit breaker. This improves the efficiency of maintenance personnel and enhances the reliability and safety of power operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 A schematic structural diagram of a circuit breaker opening and closing time measurement device based on the DC component of interference current provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0043] The embodiments of the present application provide a circuit breaker opening and closing time measurement device based on the DC component of the interference current and a method for using the device, thereby solving the technical problems of slow detection, complicated steps, and the need for a large number of equipment. This device can achieve low-cost, accurate, and efficient measurement of the circuit breaker opening and closing time without removing the grounding wire at one end of the circuit breaker and without the use of an insulating pull rod, thereby effectively avoiding the safety risks existing in traditional detection methods.

[0044] The technical solution in the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0045] The present invention provides a circuit breaker opening and closing time measurement device, comprising a circuit breaker, a conductor, a grounding wire, a grounding grid, a circuit breaker opening and closing action control terminal, an opening and closing pulse generator, a current transformer, a filter, an operational amplifier, an inductive circuit, a data acquisition card, and a host computer; wherein the circuit breaker, the conductor, the grounding wires at both ends of the circuit breaker, and the grounding grid constitute a circuit breaker fluid circuit; and the current transformer is coupled to the circuit breaker fluid circuit.

[0046] Specifically, the system applies a circuit breaker opening and closing pulse signal; collects interference current in the circuit during the circuit breaker opening and closing; extracts the DC component from the interference current and performs time-frequency analysis on the DC component; and obtains a time-frequency curve of the DC component. By analyzing this curve and locating the opening and closing moments, the opening and closing times can be determined. This simple, safe, and reliable method requires no significant human, material, or financial resources, and requires no direct contact with the circuit breaker. This improves the efficiency of maintenance personnel and enhances the reliability and safety of power operations.

[0047] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0048] Example:

[0049] like Figure 1As shown, an embodiment of the present invention provides a circuit breaker opening and closing time measurement device based on the DC component of interference current, comprising a circuit breaker 1, an isolating switch 2, a conductor, a grounding wire 3, a grounding grid 4, a circuit breaker opening and closing action control terminal 5, an opening and closing pulse generator 6, a current transformer 7, a filter 8, an operational amplifier 9, an inductive circuit 10, a data acquisition card 11, and a host 12. The circuit breaker 1, the conductor, the grounding wires 3 on both sides of the circuit breaker 1, and the grounding grid 4 form a circuit breaker fluid circuit, ensuring safe and stable operation of the circuit breaker (unsafe charges or leakage currents generated by the circuit breaker for various reasons are directed to the grounding grid via the grounding wire).

[0050] The isolating switch 2 is used to isolate the circuit breaker in the circuit to ensure that the power is cut off when the staff repairs the circuit breaker, thereby ensuring the safety of the staff.

[0051] The opening / closing pulse generator 6 is controlled by infrared remote control and is used to generate circuit breaker opening / closing signals. This signals trigger the circuit breaker 1 to perform opening / closing actions via the circuit breaker opening / closing action control terminal 5. It should be noted that the amplitude of the circuit breaker opening / closing signal should be determined before measurement begins. This amplitude is used to set the output voltage of the opening / closing pulse generator 6 and the trigger pulse size of the signal collected by the data acquisition card 11.

[0052] The current transformer 7 is a Rogowski coil with an active integrator, coupled to the circuit breaker via a fluid loop. For example, a grounding wire at one end of the circuit breaker 7 is embedded in the current transformer 7.

[0053] The filter 8 is used to filter out the original power frequency current in the circuit breaker circuit to obtain the interference current during opening and closing. For example, the filter 8 is specifically a high-pass filter with a passband designed according to measurement requirements, which has good filtering performance for low-frequency signals mainly based on power frequency.

[0054] The operational amplifier 9 has an adjustable ratio function, and an appropriate ratio is selected according to the magnitude of electromagnetic interference at the substation. For example, the operational amplifier 9 is a digital programmable operational amplifier, and an FPGA chip is used to implement internal programming of the operational amplifier.

[0055] The inductor circuit 10 is used to filter out the AC component in the interference current and obtain the DC component of the interference current. Since the interference current is mainly composed of a large number of low-frequency AC components and DC components, a capacitor can be connected in parallel at both ends of the inductor circuit to form a low-pass filter to filter out the low-frequency AC component and obtain the DC component.

[0056] The host 12 is used to trigger the data acquisition card 11 to collect the current signal of the circuit breaker fluid circuit through the current transformer 7 after detecting the circuit breaker opening and closing signal, and sequentially filter the power frequency current through the filter 8, amplify the signal through the operational amplifier 9, and filter the AC component of the interference current through the inductor circuit 10 to obtain the DC component; and is used to obtain the circuit breaker opening and closing time based on the circuit breaker opening and closing signal and the DC component.

[0057] In an optional embodiment, the host 12 detects the circuit breaker opening and closing signals through a high-voltage differential probe, and the high-voltage differential probe is installed at the opening and closing pulse generator 6.

[0058] In an optional embodiment, the host 12 specifically includes:

[0059] A receiving module, used for receiving circuit breaker opening and closing signals, and DC components in the form of a table file;

[0060] A search module is used to find the mutation point of the circuit breaker opening and closing signals in the time domain and determine the opening and closing action points; and to open the DC component table file according to the set path, find the mutation point of the DC component in the time domain based on the detection threshold, and determine the contact point of the moving and static contacts;

[0061] A drawing module, configured to draw a time curve graph according to the waveform of the circuit breaker opening and closing signal and the DC component in the time domain;

[0062] The acquisition module is used to obtain the circuit breaker opening and closing time according to the time curve, combined with the opening and closing action point and the contact / disengagement point of the moving and static contacts.

[0063] Example 2:

[0064] An embodiment of the present invention provides a method for using a circuit breaker opening and closing time measurement device based on a DC component of an interference current, comprising:

[0065] S1, test wiring;

[0066] Constructing the circuit breaker opening and closing time measuring device as described in Example 1;

[0067] S2. Parameter adjustment; including:

[0068] Set the DC component data file path and the DC component data before and after mutation detection threshold; select the operational amplifier ratio according to the size of the electromagnetic interference

[0069] S3. Signal acquisition; including:

[0070] After detecting the circuit breaker opening and closing signals, the host 12 triggers the data acquisition card 11 to collect the current signal of the circuit breaker fluid circuit through the current transformer 7, and then sequentially filters the power frequency current through the filter 8, amplifies the signal through the operational amplifier 9, and filters the AC component of the interference current through the inductor circuit 10 to obtain the DC component; after processing by the data acquisition card 11, it is uploaded to the host 12 in the form of a table file.

[0071] In this step, a high-voltage differential probe is introduced and installed at the opening and closing pulse generator 6. The host 12 detects the circuit breaker opening and closing signals through the high-voltage differential probe.

[0072] S4. Data analysis; including:

[0073] S41, the host 12 receives the circuit breaker opening and closing signals and the DC component in the form of a table file;

[0074] S42, finding a sudden change point in the time domain of the circuit breaker opening and closing signals to determine the opening and closing action points; and opening a table file of the DC component according to a set path, finding a sudden change point in the time domain of the DC component based on a detection threshold, and determining the contact / disengagement point of the moving and static contacts;

[0075] S43, drawing a time curve graph according to the waveform of the circuit breaker opening and closing signal and the DC component in the time domain;

[0076] S44, according to the time curve, combined with the opening and closing action point and the contact / disengagement point of the moving and static contacts, obtain the circuit breaker opening and closing time. Specifically:

[0077] When measuring the closing time, the closing action point is located on the time curve, recorded as t1; the contact point of the moving and static contacts is located (i.e., the moment when the current signal suddenly changes from small to large), recorded as t2; and the closing action time of the circuit breaker is obtained as t=t2-t1;

[0078] When measuring the opening time, locate the opening action point on the time curve, record it as t3; locate the separation point of the moving and static contacts (i.e. the sudden change of the current signal from large to small), record it as t4; obtain the closing action time of the circuit breaker t'=t4-t3.

[0079] In summary, compared with the existing technology, the present invention has the following beneficial effects:

[0080] In summary, the present invention enables cost-effective and accurate measurement of the opening and closing times of a circuit breaker in a double-terminal grounded state, resolving the current drawback of requiring the removal of one ground wire and the hanging of a test lead during circuit breaker opening and closing time testing. This significantly reduces the labor intensity and operating time of circuit breaker maintenance personnel while ensuring operator safety.

[0081] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A circuit breaker opening and closing time measurement device based on the DC component of interference current, characterized in that: The invention comprises a circuit breaker (1), a conductor, a grounding wire (3), a grounding grid (4), a circuit breaker opening and closing action control terminal (5), an opening and closing pulse generator (6), a current transformer (7), a filter (8), an operational amplifier (9), an inductance circuit (10), a data acquisition card (11) and a host (12); The circuit breaker (1), the conductor, the grounding wires (3) on both sides of the circuit breaker (1), and the ground grid (4) form a circuit breaker fluid circuit; the current transformer (7) is coupled to the circuit breaker fluid circuit; The opening and closing pulse generator (6) is used to send a circuit breaker opening and closing signal, and trigger the circuit breaker (1) to perform an opening and closing action through the circuit breaker opening and closing action control terminal (5); The host (12) is used to trigger the data acquisition card (11) to acquire the current signal of the circuit breaker fluid circuit through the current transformer (7) after detecting the circuit breaker opening and closing signal, and sequentially filter the power frequency current through the filter (8), amplify the signal through the operational amplifier (9), and filter the AC component of the interference current through the inductance circuit (10) to obtain the DC component; and is used to obtain the circuit breaker opening and closing time according to the circuit breaker opening and closing signal and the DC component.

2. The circuit breaker opening and closing time measuring device according to claim 1, characterized in that: The opening and closing pulse generator (6) is controlled by infrared remote control; the current transformer (7) is a Rogowski coil with an active integrator; and the operational amplifier (9) has a function of adjustable transformation ratio.

3. The circuit breaker opening and closing time measuring device according to claim 1, characterized in that: The host (12) detects the circuit breaker opening and closing signals through a high-voltage differential probe, and the high-voltage differential probe is installed at the opening and closing pulse generator (6).

4. The circuit breaker opening and closing time measuring device according to claim 1, characterized in that: The host (12) comprises: A receiving module, used for receiving circuit breaker opening and closing signals, and DC components in the form of a table file; A search module is used to find the mutation point of the circuit breaker opening and closing signals in the time domain and determine the opening and closing action points; and to open the DC component table file according to the set path, find the mutation point of the DC component in the time domain based on the detection threshold, and determine the contact point of the moving and static contacts; A drawing module, configured to draw a time curve graph according to the waveform of the circuit breaker opening and closing signal and the DC component in the time domain; The acquisition module is used to obtain the circuit breaker opening and closing time according to the time curve, combined with the opening and closing action point and the contact / disengagement point of the moving and static contacts.

5. A method for using a circuit breaker opening and closing time measuring device based on the DC component of interference current, characterized in that: include: S1, test wiring; Constructing the circuit breaker opening and closing time measuring device as claimed in claim 1; S2. Parameter adjustment; including: Set the DC component data file path and the DC component data before and after mutation detection threshold; According to the size of electromagnetic interference, select the transformation ratio of the operational amplifier S3. Signal acquisition; including: After detecting the circuit breaker opening and closing signal, the host (12) triggers the data acquisition card (11) to acquire the current signal of the circuit breaker fluid circuit through the current transformer (7), and sequentially filters the power frequency current through the filter (8), amplifies the signal through the operational amplifier (9), and filters the AC component of the interference current through the inductance circuit (10), thereby acquiring the DC component; the DC component is processed by the data acquisition card (11) and uploaded to the host (12) in the form of a table file; S4. Data analysis; including: S41, the host (12) receives a circuit breaker opening and closing signal and a DC component in a table file format; S42, finding a sudden change point in the time domain of the circuit breaker opening and closing signals to determine the opening and closing action points; and opening a table file of the DC component according to a set path, finding a sudden change point in the time domain of the DC component based on a detection threshold, and determining the contact / disengagement point of the moving and static contacts; S43, drawing a time curve graph according to the waveform of the circuit breaker opening and closing signal and the DC component in the time domain; S44. Obtain the circuit breaker opening and closing time according to the time curve, in combination with the opening and closing action points and the contact / disengagement points of the moving and static contacts.

6. The method of use according to claim 5, wherein: In the S1, an infrared remote control is used to control the opening and closing pulse generator (6); the current transformer (7) is selected as a Rogowski coil with an active integrator; and an operational amplifier (9) with an adjustable transformation ratio function is selected.

7. The method of use according to claim 5, wherein: A high-voltage differential probe is introduced into the S3 and installed at the opening and closing pulse generator (6), and the host (12) detects the circuit breaker opening and closing signals through the high-voltage differential probe.

8. The method of use according to claim 5, wherein: In said S44: When measuring the closing time, the closing action point is located on the time curve, recorded as t1; the contact point of the moving and static contacts is located, recorded as t2; and the closing action time of the circuit breaker is obtained as t=t2-t1; When measuring the opening time, locate the opening action point on the time curve, record it as t3; locate the separation point of the moving and static contacts, record it as t4; and obtain the closing action time of the circuit breaker t'=t4-t3.

Images