Anti-misoperation protection unit for circuit breaker

Abstract

The utility model provides a circuit breaker, which 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] The utility model relates to the field of electrical equipment, more particularly to the field of circuit breaker technology of electrical equipment. BACKGROUND

[0002] A circuit breaker is an automatic switching device used to protect electrical circuits, widely used in power systems, industrial automation, building electrical and transportation fields. The main function of the circuit breaker is to detect current abnormalities and quickly cut off the power supply to protect equipment and personnel from the impact of current overload and short circuit faults.

[0003] The circuit breaker usually has two protection functions, MCR protection (Making Current Release) and HSISC protection (High Setting Instantaneous Short-circuit Current).

[0004] Circuit breaker misprotection usually refers to the protection behavior of the circuit breaker incorrectly acting in the case where it should not perform MCR protection or HSISC protection. As an important electrical protection device, the circuit breaker will have a serious impact on the stability of the power grid if misprotection occurs, such as causing unnecessary circuit interruption, affecting normal power supply, and even causing economic losses such as production interruption and data loss. At the same time, due to the tripping of the circuit breaker under non-fault conditions, the stability and reliability of the system will be affected, which may lead to unstable operation of the equipment and further cause greater faults. In addition, frequent misprotection will also cause damage to the circuit breaker itself or related components, increasing maintenance costs and downtime.

[0005] Therefore, it is necessary to optimize the circuit breaker to prevent misprotection of the circuit breaker under interference. SUMMARY

[0006] The utility model aims at overcoming the defects of the prior art, and provides a misprotection prevention unit for a circuit breaker, which comprises:

[0007] A signal acquisition and processing module configured to sample signals of the circuit in which the circuit breaker is located and output the sampled signals;

[0008] An MCR protection threshold module configured to store an MCR protection threshold;

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

[0010] a first pulse width detection circuit, wherein the first pulse width detection circuit continuously detects the pulse width of the first trigger signal and continuously outputs a first pulse width;

[0011] An HSISC protection threshold module is configured to store an HSISC protection threshold;

[0012] a second comparator configured to compare the amplitude of the sampling signal with the HSISC protection threshold; the second comparator continuously outputting a second trigger signal only when the amplitude of the sampling signal is greater than the HSISC protection threshold;

[0013] a second pulse width detection circuit, which continuously detects the pulse width of the second trigger signal and continuously outputs a second pulse width;

[0014] a logic circuit, wherein the logic gate circuit is configured to perform a logic judgment on the first pulse width and the second pulse width, and to issue a third trigger signal when a result of the logic judgment satisfies a specified condition;

[0015] A pulse width modulation circuit is configured to output a driving pulse according to the third trigger signal to drive an actuator of the circuit breaker to cut off the circuit.

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

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

[0018] According to the anti-error protection unit of the present invention, preferably, 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 driving pulse.

[0019] According to the anti-error protection unit of the present invention, preferably, the MCR protection threshold, the HSISC protection threshold and the pulse width threshold are set according to actual circuit parameters.

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

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

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

[0023] According to the anti-error protection unit of the present invention, preferably, the MCR protection threshold module and the HSISC protection threshold module also include 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 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.

[0024] The present invention also provides a method for the above-mentioned anti-mistake 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 a sampling signal, and inputs the sampling signal into the first comparator and the second comparator respectively;

[0026] The first comparator compares the amplitude of the sampling 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 sampling 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 of the first trigger signal and outputs a first pulse width; the second pulse width detection circuit detects the pulse width of the second trigger signal and outputs a second pulse width;

[0028] The logic gate circuit performs logic judgment based on the first pulse width and the second pulse width, and triggers the pulse width modulation circuit to send a driving pulse to cut off the circuit when at least one of the first pulse width and the second pulse width is greater than a pulse width threshold.

[0029] Compared with the existing technology, the advantages of the present invention are: by setting an anti-misprotection unit in the circuit breaker, sampling the signal in the circuit and performing double comparison and judgment, the interference signal is effectively screened out, and the MCR misprotection and HSISC misprotection caused by environmental factors, on-site electromagnetic interference, etc. are prevented, the circuit breaker and circuit load are protected, and the safety, stability and reliability of the system are guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following is a further description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0031] Figure 1Schematic diagram of an anti-misuse protection unit according to an embodiment of the present invention;

[0032] Figure 2 1 is a flowchart of the anti-error protection unit according to an embodiment of the present utility model; DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] For those skilled in the art, circuit breakers typically have two important protection functions: MCR protection and HSISC protection. MCR protection takes effect at the moment the circuit breaker is closed. Its function is to prevent the circuit breaker from being damaged by a current surge exceeding its limit connection capacity when it is connected. MCR protection is suitable for instantaneous high current conditions that may occur when the circuit breaker is closed, such as motor starting. HSISC protection usually takes effect some time after the circuit breaker is closed. When an excessive fault current 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 a short circuit fault in the system after the circuit breaker is closed.

[0035] Once MCR misprotection or HSISC misprotection occurs, the circuit breaker will malfunction, affecting the safety of the circuit or system.

[0036] According to one embodiment of the present invention, Figure 1 As shown, a mis-protection unit 100 for a circuit breaker is provided, which can effectively reduce mis-protection. Figure 1 FIG. 1 shows a schematic structural diagram of the anti-error protection unit 100 .

[0037] The anti-error 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 of the signal acquisition and processing module 10 is coupled to the first input of the first comparator 30A, and the output of the MCR protection threshold module 20A is coupled to the second input of the first comparator 30A. The second output of the signal acquisition and processing module 10 is coupled to the first input of the second comparator 30B, and the output of the HSISC protection threshold module 20B is coupled to the second input of the second comparator 30B. The output of the first comparator 30A is coupled to the input of the first pulse width detection circuit 40A, and the output of the first pulse width detection circuit 40A is coupled to the first input of the logic gate circuit 50. The output of the second comparator 30B is coupled to the input of the second pulse width detection circuit 40B, and the output of the second pulse width detection circuit 40B is coupled to the second input of the logic gate circuit 50. The output of the logic gate circuit 50 is coupled to the input of the pulse width modulation circuit 60. The output of the pulse width modulation circuit 60 is coupled to the actuator 70 of the circuit breaker.

[0039] The anti-error protection unit 100 is configured to sample the signal of the circuit where the circuit breaker is located to obtain a sampling signal, and then compare the sampling signal with the MCR protection threshold and the HSISC protection threshold respectively, and trigger the pulse width detection when the sampling 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 driving pulse to drive the circuit breaker's actuator to cut off the circuit. Figure 1 , the working process of the anti-error protection unit 100 is described in detail.

[0040] The signal acquisition and processing module 10 is configured to sample the voltage signal of the circuit in which the circuit breaker is located and obtain a 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. 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 issues the first trigger signal S1 only while 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 terminal of the first comparator 30A.

[0042] The first trigger signal S1 triggers the first pulse width detection circuit 40A. The first pulse width detection circuit 40A is configured to continuously detect the pulse width of the first trigger signal S1 and continuously output a first pulse width T1. The first pulse width T1 is input to the first input of the logic gate circuit 50 via the output 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 issues the second trigger signal S2 only while 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 terminal of the second comparator 30B.

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

[0045] The logic gate circuit 50 is configured to perform a logic 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 logic OR judgment on the first pulse width T1 and the second pulse width T2.

[0046] When the logic gate circuit 50's logical determination meets a specified condition, it issues a third trigger signal S3, triggering the 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 a pulse-width threshold Th1. Once triggered, the pulse-width modulation circuit 60 outputs a drive pulse, driving the circuit breaker's actuator 70 to disconnect the circuit. The pulse width of the drive pulse emitted by the pulse-width modulation circuit 60 ensures that the actuator 70 effectively disconnects the circuit. Preferably, the pulse width of the drive pulse is no less than 10 ms.

[0047] The circuit breaker in the above embodiment of the present invention adopts a double comparison judgment, that is, the amplitude and pulse width of the sampling signal are compared and judged respectively, and only when both meet the specified conditions, the actuator is driven to cut off the circuit, so that it can effectively screen out fault interference signals, thereby preventing itself from being affected by environmental factors and electromagnetic interference and causing MCR false protection or HSISC false protection.

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

[0049] In some embodiments of the present invention, the sampling signal S0 sampled and acquired 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 also includes a memory, which is 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] According to the embodiment of the present invention, there is a certain relationship between the pulse widths of the first trigger signal S1 and the second trigger signal S2 and the pulse width of the sampling signal S0.

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

[0053] While the amplitude of the sampled signal S0 exceeds and remains above 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 continuously changes as the first trigger signal S1 is continuously output. Because 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 is triggered and outputs a drive pulse, driving the circuit breaker actuator 70 to disconnect 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 actuator 70 is not 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 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 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, TS is 100ms.

[0055] In some embodiments of the present invention, the MCR protection threshold and HSISC protection threshold can be selected based on actual circuit operating conditions. In some embodiments of the present invention, the user can set the MCR protection threshold and HSISC protection threshold on the circuit breaker. This configuration allows the circuit breaker to more accurately adapt to the circuit, effectively preventing misconfiguration of MCR and HSISC protections.

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

[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 that generates a corresponding MCR protection threshold voltage or HSISC protection threshold voltage according to 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 when powered on, the digital potentiometer reads the MCR protection threshold or HSISC protection threshold recorded in the memory and generates a 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, Figure 2 As shown, a method for preventing malfunction of a circuit breaker is provided, comprising the following steps:

[0061] In step 110, the signal acquisition and processing module 10 samples the signal of the circuit where the circuit breaker is located to obtain a sampled signal S0. The 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] In 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 issues 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 issues the second trigger signal S2. Otherwise, the circuit breaker does not operate (step 200).

[0063] In step 130 , the first trigger signal S1 triggers the first pulse width detection circuit 40A to continuously detect and output the first pulse width T1 ; the second trigger signal S2 triggers the second pulse width detection circuit 40B to continuously detect and output the second pulse width T2 .

[0064] In step 140, logic gate circuit 50 performs a logical evaluation on the first pulse width T1 and the second pulse width T2 outputted by first pulse width detection circuit 40A and second pulse width detection circuit 40B, respectively, in step 130. If either first pulse width T1 or second pulse width T2 exceeds pulse width threshold Th1, pulse width modulation circuit 60 is triggered to generate a drive pulse. Otherwise, the circuit breaker does not operate (step 200).

[0065] Step 150: The driving pulse drives the actuator 70 of the circuit breaker, and the actuator 70 operates to cut off the circuit.

[0066] Through the specific embodiments of the utility model described above, the problem of circuit breaker misprotection can be effectively solved.

[0067] By setting up an anti-misprotection unit in the circuit breaker, sampling the signals in the circuit and performing double comparison and judgment, the interference signals can be effectively screened out, preventing MCR misprotection and HSISC misprotection 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.

[0068] In the above embodiments of the present invention, although MCR protection and HSISC protection are used for explanation, the technical solution proposed by the present invention is not limited to the above two types of protection. In actual applications, other types of protection can also be set according to working conditions.

[0069] Although the present invention has been described through preferred embodiments, the present invention is not limited to the embodiments described herein, and includes various changes and modifications that may be made without departing from the scope of the present invention.

Claims

1. A circuit breaker anti-error protection unit, characterized in that: The anti-error protection unit includes: a signal acquisition and processing module, configured to sample the signal of the circuit where the circuit breaker is located and output a sampled signal; An MCR protection threshold module is configured to store an MCR protection threshold; a first comparator configured to compare the amplitude of the sampling signal with the MCR protection threshold; the first comparator continuously outputting a first trigger signal only when the amplitude of the sampling signal is greater than the MCR protection threshold; a first pulse width detection circuit, wherein the first pulse width detection circuit continuously detects the pulse width of the first trigger signal and continuously outputs a first pulse width; An HSISC protection threshold module is configured to store an HSISC protection threshold; a second comparator configured to compare the amplitude of the sampling signal with the HSISC protection threshold; the second comparator continuously outputting a second trigger signal only when the amplitude of the sampling signal is greater than the HSISC protection threshold; a second pulse width detection circuit, which continuously detects the pulse width of the second trigger signal and continuously outputs a second pulse width; a logic circuit configured to perform a logic judgment on the first pulse width and the second pulse width, and to issue a third trigger signal when a result of the logic judgment satisfies a specified condition; A pulse width modulation circuit is configured to output a driving pulse according to the third trigger signal to drive an actuator of the circuit breaker to cut off the circuit.

2. The anti-error protection unit according to claim 1, characterized in that: The sampling signal is at least one of a voltage signal, a current signal, a power signal or a frequency signal.

3. The anti-error protection unit according to claim 1, characterized in that: The logic circuit is an OR gate circuit.

4. The anti-error protection unit according to claim 1, characterized in that: When at least one of the first pulse width and the second pulse width is greater than a pulse width threshold, the pulse width modulation circuit is triggered to output a driving pulse.

5. The anti-error protection unit according to claim 4, characterized in that: The MCR protection threshold, the HSISC protection threshold, and the pulse width threshold are set according to actual circuit parameters.

6. The anti-error protection unit according to any one of claims 1 to 4, characterized in that: The pulse width threshold is 5 ms.

7. The anti-error protection unit according to any one of claims 1 to 4, characterized in that: The first pulse width and the second pulse width are related to a pulse width of the sampling signal.

8. The anti-error protection unit according to any one of claims 1 to 4, characterized in that: The signal acquisition and processing module is further configured to record electrical data when a fault occurs in the circuit.

9. The anti-error protection unit according to any one of claims 1 to 4, characterized in that: The MCR protection threshold module and the HSISC protection threshold module also 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 a corresponding MCR protection threshold voltage or HSISC protection threshold voltage output.

10. The anti-error protection unit according to any one of claims 1 to 4, characterized in that: The circuit breaker is an air circuit breaker.

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