Anti-misoperation protection unit for circuit breaker

Abstract

The invention provides a circuit breaker. The circuit breaker comprises an anti-misoperation protection unit. The anti-misoperation protection unit comprises a signal acquisition and processing module, a comparator, a pulse width detection circuit, a logic gate circuit, a pulse width modulation circuit and the like. And the anti-misoperation protection unit is configured to sample signals of a circuit where the circuit breaker is located, perform dual comparison judgment, and drive an execution mechanism of the circuit breaker to cut off the circuit when all comparison results meet specified conditions.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment, and more specifically to the field of circuit breaker technology for electrical equipment. Background Technology

[0002] A circuit breaker is an automatic switching device used to protect circuits. It is widely used in power systems, industrial automation, building electrical systems, and transportation. The main function of a circuit breaker is to detect abnormal current and quickly disconnect the power supply to the circuit to protect equipment and personnel from faults such as current overload and short circuit.

[0003] Circuit breakers typically have two protection functions: MCR protection (Making Current Release) and HSISC protection (High Setting Instantaneous Short-circuit Current).

[0004] Circuit breaker maloperation typically refers to the incorrect tripping of a circuit breaker when it should not be performing MCR or HSISC protection. As a crucial electrical protection device, circuit breaker maloperation can severely impact power grid stability, leading to unnecessary circuit interruptions, disrupting normal power supply, and potentially causing economic losses such as production disruptions and data loss. Furthermore, because circuit breakers trip under non-fault conditions, system stability and reliability are affected, potentially causing equipment instability and leading to larger failures. In addition, frequent maloperation can damage the circuit breaker itself or related components, increasing maintenance costs and downtime.

[0005] Therefore, it is necessary to optimize the circuit breaker to prevent it from malfunctioning under interference. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a misoperation prevention protection unit for circuit breakers, the misoperation prevention protection unit comprising:

[0007] The signal acquisition and processing module is configured to sample the signal of the circuit where the circuit breaker is located and output the sampled signal;

[0008] The MCR protection threshold module is configured to store MCR protection thresholds;

[0009] A first comparator is configured to compare the amplitude of the sampled signal with the MCR protection threshold; the first comparator continuously outputs a first trigger signal only for a period of time when the amplitude of the sampled signal is greater than the MCR protection threshold.

[0010] The first pulse width detection circuit continuously detects the pulse width of the first trigger signal and continuously outputs the first pulse width.

[0011] The HSISC protection threshold module is configured to store HSISC protection thresholds.

[0012] A second comparator is configured to compare the amplitude of the sampled signal with the HSISC protection threshold; the second comparator continuously outputs a second trigger signal only for a period of time during which the amplitude of the sampled signal is greater than the HSISC protection threshold.

[0013] The second pulse width detection circuit continuously detects the pulse width of the second trigger signal and continuously outputs the second pulse width.

[0014] The logic circuit is configured to perform a logical judgment on the first pulse width and the second pulse width, and when the logical judgment result meets a specified condition, a third trigger signal is issued.

[0015] A pulse width modulation circuit, which outputs a drive pulse according to the third trigger signal to drive the actuator of the circuit breaker to cut off the circuit.

[0016] According to the anti-misoperation protection unit of the present invention, preferably, the sampling signal is at least one of voltage signal, current signal, power signal or frequency signal.

[0017] According to the anti-misoperation protection unit of the present invention, preferably, the logic circuit is an OR gate circuit.

[0018] According to the anti-misoperation protection unit of the present invention, preferably, the pulse width modulation circuit is triggered to output a drive pulse when at least one of the first pulse width and the second pulse width is greater than the pulse width threshold.

[0019] According to the anti-misoperation protection unit of the present invention, preferably, the first trigger threshold, the second trigger threshold and the pulse width threshold are set according to the actual circuit parameters.

[0020] According to the anti-misoperation protection unit of the present invention, preferably, the pulse width threshold is 5ms.

[0021] According to the anti-misoperation protection unit of the present invention, preferably, the first pulse width and the second pulse width are related to the pulse width of the sampled signal.

[0022] According to the anti-misoperation protection unit of the present invention, preferably, the signal acquisition and processing module is further configured to record electrical data when the circuit malfunctions.

[0023] According to the anti-misoperation protection unit of the present invention, preferably, the MCR protection threshold module and the HSISC protection threshold module further include a microprocessor and a memory. The microprocessor writes the set MCR protection threshold or HSISC protection threshold into the memory. When powered on, the digital potentiometer reads the MCR protection threshold or the HSISC protection threshold recorded in the memory and generates the corresponding MCR protection threshold voltage or HSISC protection threshold voltage output.

[0024] The present invention also provides a method for the above-mentioned anti-misoperation protection unit, the method comprising:

[0025] The signal acquisition and processing module samples the signal of the circuit where the circuit breaker is located to obtain the sampled signal, and inputs it to the first comparator and the second comparator respectively.

[0026] The first comparator compares the amplitude of the sampled signal with the MCR protection threshold, and issues a first trigger signal when the amplitude is greater than the MCR protection threshold; the second comparator compares the amplitude of the sampled signal with the HSISC protection threshold, and issues a second trigger signal when the amplitude is greater than the HSISC protection threshold.

[0027] The first pulse width detection circuit detects the pulse width based on the first trigger signal and outputs the first pulse width; the second pulse width detection circuit detects the pulse width based on the second trigger signal and outputs the second pulse width.

[0028] The logic gate circuit makes a logical judgment based on the first pulse width and the second pulse width. When at least one of the first pulse width and the second pulse width is greater than the pulse width threshold, the pulse width modulation circuit is triggered to issue a driving pulse to cut off the circuit.

[0029] Compared with the prior art, the advantages of the present invention are as follows: by setting an anti-misoperation protection unit in the circuit breaker, the signals in the circuit are sampled and double-compared for judgment, effectively filtering out interference signals, preventing MCR misoperation and HSISC misoperation caused by environmental factors, on-site electromagnetic interference, etc., protecting the circuit breaker and circuit load, and ensuring the safety, stability and reliability of the system. Attached Figure Description

[0030] The embodiments of the present invention will be further described below with reference to the accompanying drawings, wherein:

[0031] Figure 1 This is a schematic diagram of the anti-misoperation protection unit according to an embodiment of the present invention;

[0032] Figure 2 This is a flowchart illustrating the operation of the anti-misoperation protection unit according to an embodiment of the present invention; Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] For those skilled in the art, circuit breakers typically possess two important protection functions: MCR protection and HSISC protection. MCR protection activates the instant the circuit breaker closes, preventing damage caused by current surges exceeding its overcurrent limit during closing. MCR protection is suitable for situations involving instantaneous high currents that may occur during circuit breaker closing, such as motor starting. HSISC protection typically activates some time after the circuit breaker has closed. When an overcurrent fault is detected, it usually issues a trip command within 10 milliseconds to protect the circuit breaker from damage caused by excessive current. HSISC protection is suitable for rapid response to short-circuit faults in the system after the circuit breaker has closed.

[0035] If a false MCR or HSISC protection occurs, the circuit breaker will operate incorrectly, affecting the safety of the circuit or system.

[0036] According to one embodiment of the present invention, such as Figure 1 As shown, a circuit breaker anti-misoperation protection unit 100 is provided that can effectively reduce false protection. Figure 1 A schematic diagram of the anti-misoperation protection unit 100 is shown.

[0037] The anti-misoperation protection unit 100 includes a signal acquisition and processing module 10, an MCR protection threshold module 20A, an HSISC protection threshold module 20B, a first comparator 30A, a second comparator 30B, a first pulse width detection circuit 40A, a second pulse width detection circuit 40B, a logic gate circuit 50, and a pulse width modulation circuit 60.

[0038] The first output terminal of the signal acquisition and processing module 10 is coupled to the first input terminal of the first comparator 30A, and the output terminal of the MCR protection threshold module 20A is coupled to the second input terminal of the first comparator 30A. The second output terminal of the signal acquisition and processing module 10 is coupled to the first input terminal of the second comparator 30B, and the output terminal of the HSISC protection threshold module 20B is coupled to the second input terminal of the second comparator 30B. The output terminal of the first comparator 30A is coupled to the input terminal of the first pulse width detection circuit 40A, and the output terminal of the first pulse width detection circuit 40A is coupled to the first input terminal of the logic gate circuit 50. The output terminal of the second comparator 30B is coupled to the input terminal of the second pulse width detection circuit 40B, and the output terminal of the second pulse width detection circuit 40B is coupled to the second input terminal of the logic gate circuit 50. The output terminal of the logic gate circuit 50 is coupled to the input terminal of the pulse width modulation circuit 60. The output terminal of the pulse width modulation circuit 60 is coupled to the actuator 70 of the circuit breaker.

[0039] The anti-misoperation protection unit 100 is configured to sample the signals of the circuit where the circuit breaker is located to obtain a sampled signal, then compare the sampled signal with the MCR protection threshold and the HSISC protection threshold respectively, and trigger pulse width detection when the sampled signal is greater than at least one of the MCR protection threshold and the HSISC protection threshold. When the pulse width detection result meets the specified conditions, the circuit breaker sends a drive pulse to drive the circuit breaker's actuator to cut off the circuit. The following is in conjunction with... Figure 1 The working process of the anti-misoperation protection unit 100 is explained in detail.

[0040] The signal acquisition and processing module 10 is configured to sample the voltage signal of the circuit breaker circuit and acquire a sampled signal S0. The acquired sampled signal S0 is input to the first input terminal of the first comparator 30A and the second input terminal of the second comparator 30B via the first and second output terminals of the signal acquisition and processing module 10, respectively. In this embodiment, the sampled signal S0 is a voltage signal.

[0041] The first comparator 30A is configured to compare the amplitude of the sampled signal S0 with the MCR protection threshold generated by the MCR protection threshold module 20A. The first comparator 30A continuously outputs a first trigger signal S1 only for a period of time when the voltage amplitude X of the sampled signal S0 is greater than the MCR protection threshold. The first trigger signal S1 is input to the first pulse width detection circuit 40A via the output of the first comparator 30A.

[0042] The first trigger signal S1 triggers the first pulse width detection circuit 40A, which is configured to continuously detect the pulse width of the first trigger signal S1 and continuously output the first pulse width T1. The first pulse width T1 is input to the first input terminal of the logic gate circuit 50 via the output terminal of the first pulse width detection circuit 40A.

[0043] The second comparator 30B is configured to compare the amplitude of the sampled signal S0 with the HSISC protection threshold generated by the HSISC protection threshold module 20B. The second comparator 30B continuously outputs a second trigger signal S2 only for a period of time when the voltage amplitude X of the sampled signal S0 is greater than the HSISC protection threshold. The second trigger signal S2 is input to the second pulse width detection circuit 40B via the output of the second comparator 30B.

[0044] The second trigger signal S2 triggers the second pulse width detection circuit 40B, which is configured to continuously detect the pulse width of the second trigger signal S2 and continuously output the second pulse width T2. The second pulse width T2 is input to the second input terminal of the logic gate circuit 50 via the output terminal of the second pulse width detection circuit 40B.

[0045] The logic gate circuit 50 is configured to perform a logical judgment on the first pulse width T1 and the second pulse width T2. In this embodiment, the logic gate circuit 50 is an OR gate circuit. That is, the logic gate circuit 50 performs a logical OR judgment on the first pulse width T1 and the second pulse width T2.

[0046] When the logic judgment result of logic gate circuit 50 meets the specified condition, a third trigger signal S3 is issued to trigger pulse width modulation circuit 60. In this embodiment, the specified condition is that at least one of the first pulse width T1 and the second pulse width T2 is greater than the pulse width threshold Th1. After being triggered, pulse width modulation circuit 60 outputs a drive pulse to drive the actuator 70 of the circuit breaker to cut off the circuit. The pulse width of the drive pulse issued by pulse width modulation circuit 60 is used to ensure that the actuator 70 effectively cuts off the circuit. Preferably, the pulse width of the drive pulse is not less than 10ms.

[0047] The circuit breaker in the above embodiments of the present invention employs a dual comparison judgment, that is, it compares and judges the amplitude and pulse width of the sampled signal respectively, and drives the actuator to cut off the circuit only when both of them meet the specified conditions, so that it can effectively filter out fault interference signals, thereby preventing itself from being falsely protected by MCR or HSISC due to environmental factors and electromagnetic interference.

[0048] In some embodiments of the present invention, the anti-misoperation protection unit 100 can also be used to reduce the misoperation of the air circuit breaker.

[0049] In some embodiments of the present invention, the sampling signal S0 obtained by the signal acquisition and processing module 10 may also be a current signal, a power signal, or a frequency signal.

[0050] In some embodiments of the present invention, the signal acquisition and processing module 10 further includes a memory configured to record detailed electrical data when a fault occurs, providing detailed data support for fault analysis, thereby helping to determine the specific location of the fault and quickly locate the problem.

[0051] In the embodiments of the present invention, the pulse widths of the first trigger signal S1 and the second trigger signal S2 are related to the pulse width of the sampling signal S0.

[0052] Since the pulse width processing procedures for the first trigger signal S1 and the second trigger signal S2 are exactly the same, the following explanation will take how to obtain the pulse width T1 of the first trigger signal S1 as an example.

[0053] While the amplitude of the sampled signal S0 is greater than and remains greater than the MCR protection threshold, the first comparator continuously outputs the first trigger signal S1. The first pulse width detection circuit continuously detects the duration (i.e., pulse width) of the first trigger signal S1 and continuously outputs the first pulse width T1. Therefore, the value of the output first pulse width T1 changes continuously with the continuous output of the first trigger signal S1. Since the first pulse width T1 is continuously input to the logic gate circuit 50, when it is determined that the input first pulse width T1 is greater than the preset pulse width threshold Th1, the pulse width modulation circuit 60 will be triggered and output a drive pulse, driving the circuit breaker's actuator 70 to cut off the circuit. Obviously, the value of the first pulse width T1 may be equal to or less than the pulse width of the sampled signal S0. When the pulse width of the sampled signal S0 is less than the preset pulse width threshold Th1, the maximum value of the first pulse width T1 (during the current pulse period of the sampled signal S0, the same below) is equal to the pulse width of the sampled signal S0, and the circuit breaker's actuator 70 will not be driven to execute; when the pulse width of the sampled signal S0 is greater than the preset pulse width threshold Th1, the maximum value of the first pulse width T1 is equal to the preset pulse width threshold Th1, therefore, the value of T1 is less than the pulse width of the sampled signal S0, and the circuit breaker's actuator 70 is driven to execute; when the pulse width of the sampled signal S0 is equal to the preset pulse width threshold Th1, the maximum value of T1 is also equal to the pulse width of the sampled signal S0, and the circuit breaker's actuator 70 is also driven to execute.

[0054] In some embodiments of the present invention, the MCR protection is effective within the TS time after the circuit breaker is closed, and the HSISC protection is effective after the TS time after the circuit breaker is closed. Preferably, the TS is 100ms.

[0055] In some embodiments of the present invention, the MCR protection threshold and HSISC protection threshold can be selected according to the actual operating conditions of the circuit. In some embodiments of the present invention, the user can set the MCR protection threshold and HSISC protection threshold on the circuit breaker himself. The above settings enable the circuit breaker to more accurately adapt to the circuit and effectively prevent false MCR and false HSISC protection.

[0056] In some embodiments of the present invention, the pulse width threshold Th1 can be selected according to the actual operating conditions of the circuit. Preferably, the pulse width threshold Th1 is 5ms.

[0057] In some embodiments of the present invention, the MCR protection threshold module 20A or the HSISC protection threshold module 20B includes a digital potentiometer. The digital potentiometer generates a corresponding MCR protection threshold voltage or HSISC protection threshold voltage based on the MCR protection threshold or HSISC protection threshold set by the circuit breaker.

[0058] In some embodiments of the present invention, the MCR protection threshold module 20A or the HSISC protection threshold module 20B further includes a microprocessor and a memory. The microprocessor writes the set MCR protection threshold or HSISC protection threshold into the memory, and the digital potentiometer reads the MCR protection threshold or HSISC protection threshold recorded in the memory when powered on and generates the corresponding MCR protection threshold voltage or HSISC protection threshold voltage output.

[0059] In some embodiments of the present invention, the actuator 70 is a tripping mechanism.

[0060] According to one embodiment of the present invention, such as Figure 2 As shown, a method for preventing circuit breaker malfunction is provided, comprising the following steps:

[0061] Step 110: The signal acquisition and processing module 10 samples the signal of the circuit where the circuit breaker is located to obtain the sampled signal S0. The obtained sampled signal S0 is input to the first input terminal of the first comparator 30A and the second input terminal of the second comparator 30B via the first and second output terminals of the signal acquisition and processing module 10, respectively.

[0062] Step 120: The first comparator 30A compares the amplitude X of the sampled signal S0 with the MCR protection threshold. While the amplitude X is greater than the MCR protection threshold, the first comparator 30A continuously sends the first trigger signal S1. The second comparator 30B compares the amplitude X of the sampled signal S0 with the HSISC protection threshold. While the amplitude X is greater than the HSISC protection threshold, the second comparator 30B continuously sends the second trigger signal S2. Otherwise, the circuit breaker does not operate (step 200).

[0063] Step 130: The first trigger signal S1 will trigger the first pulse width detection circuit 40A to continuously detect and continuously output the first pulse width T1; the second trigger signal S2 will trigger the second pulse width detection circuit 40B to continuously detect and continuously output the second pulse width T2.

[0064] In step 140, logic gate circuit 50 performs logical judgment on the first pulse width T1 and the second pulse width T2 output by the first pulse width detection circuit 40A and the second pulse width detection circuit 40B in step 130, respectively. When the first pulse width T1 or the second pulse width T2 is greater than the pulse width threshold Th1, the pulse width modulation circuit 60 is triggered to issue a drive pulse; otherwise, the circuit breaker does not operate (step 200).

[0065] Step 150: Drive the actuator 70 of the circuit breaker with a drive pulse, and the actuator 70 cuts off the circuit.

[0066] Through the specific embodiments of the present invention described above, the problem of circuit breaker malfunction can be effectively solved.

[0067] By setting up a false protection unit in the circuit breaker, the signals in the circuit are sampled and double-compared to effectively filter out interference signals, prevent false protection of MCR and HSISC caused by environmental factors and on-site electromagnetic interference, protect the circuit breaker and circuit load, and ensure the safety, stability and reliability of the system.

[0068] Although the above embodiments of the present invention have described MCR protection and HSISC protection, the technical solutions proposed by the present invention are not limited to the above two protection types. In practical applications, other types of protection can also be set according to the working conditions.

[0069] While the present invention has been described through preferred embodiments, it is not limited to the embodiments described herein, and various changes and modifications are made without departing from the scope of the invention.

Claims

1. A misoperation prevention protection unit for a circuit breaker, the misoperation prevention protection unit comprising: The signal acquisition and processing module is configured to sample the signal of the circuit where the circuit breaker is located and output the sampled signal; The MCR protection threshold module is configured to store MCR protection thresholds; A first comparator is configured to compare the amplitude of the sampled signal with the MCR protection threshold; the first comparator continuously outputs a first trigger signal only for a period of time when the amplitude of the sampled signal is greater than the MCR protection threshold. The first pulse width detection circuit continuously detects the pulse width of the first trigger signal and continuously outputs the first pulse width. The HSISC protection threshold module is configured to store HSISC protection thresholds. A second comparator is configured to compare the amplitude of the sampled signal with the HSISC protection threshold; the second comparator continuously outputs a second trigger signal only for a period of time during which the amplitude of the sampled signal is greater than the HSISC protection threshold. The second pulse width detection circuit continuously detects the pulse width of the second trigger signal and continuously outputs the second pulse width. The logic circuit is configured to perform a logical judgment on the first pulse width and the second pulse width, and when the logical judgment result meets a specified condition, a third trigger signal is issued. A pulse width modulation circuit, which outputs a drive pulse according to the third trigger signal to drive the actuator of the circuit breaker to cut off the circuit.

2. The anti-misoperation protection unit according to claim 1, wherein the sampling signal is at least one of voltage signal, current signal, power signal or frequency signal.

3. The anti-misoperation protection unit according to claim 1, wherein the logic circuit is an OR gate circuit.

4. The anti-misoperation protection unit according to claim 1, wherein when at least one of the first pulse width and the second pulse width is greater than the pulse width threshold, the pulse width modulation circuit is triggered to output a drive pulse.

5. The anti-misoperation protection unit according to any one of claims 1-4, wherein the first trigger threshold, the second trigger threshold and the pulse width threshold are set according to actual circuit parameters.

6. The anti-misoperation protection unit according to any one of claims 1-4, wherein the pulse width threshold is 5ms.

7. The anti-misoperation protection unit according to any one of claims 1-4, wherein the first pulse width and the second pulse width are related to the pulse width of the sampling signal.

8. The anti-malfunction protection unit according to any one of claims 1-4, wherein the signal acquisition and processing module is further configured to record electrical data when the circuit malfunctions.

9. The anti-misoperation protection unit according to any one of claims 1-4, wherein the MCR protection threshold module and the HSISC protection threshold module further include a microprocessor and a memory, wherein the microprocessor writes the set MCR protection threshold or HSISC protection threshold into the memory, and the digital potentiometer reads the MCR protection threshold or the HSISC protection threshold recorded in the memory when powered on and generates a corresponding MCR protection threshold voltage or HSISC protection threshold voltage output.

10. A method for an anti-misoperation protection unit according to any one of claims 1-9, the method comprising: The signal acquisition and processing module samples the signal of the circuit where the circuit breaker is located to obtain the sampled signal, and inputs it to the first comparator and the second comparator respectively. The first comparator compares the amplitude of the sampled signal with the MCR protection threshold, and issues a first trigger signal when the amplitude is greater than the MCR protection threshold. The second comparator compares the amplitude of the sampled signal with the HSISC protection threshold, and issues a second trigger signal when the amplitude is greater than the HSISC protection threshold. The first pulse width detection circuit detects the pulse width based on the first trigger signal and outputs the first pulse width. The second pulse width detection circuit detects the pulse width based on the second trigger signal and outputs the second pulse width. The logic gate circuit makes a logical judgment based on the first pulse width and the second pulse width. When at least one of the first pulse width and the second pulse width is greater than the pulse width threshold, the pulse width modulation circuit is triggered to issue a driving pulse to cut off the circuit.

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