Arc light channel self-checking circuit and method of arc light protection device

Abstract

The invention discloses an arc light channel self-checking circuit and method of an arc light protection device. The arc light channel self-checking circuit comprises a control unit, a light source driving module and a photoelectric detection loop, wherein the light source driving module and the photoelectric detection loop are connected through an optical fiber. The light source driving module is used for emitting light with a set wavelength for self-inspection under the control of the control unit; the photoelectric detection loop is used for receiving an optical signal transmitted through the optical fiber, converting the optical signal into a voltage signal and outputting the voltage signal to the control unit; and the control unit compares the voltage signal with a preset threshold value, and judges whether the arc light channel has a fault or not according to a comparison result. The arc light channel self-checking circuit of the device realizes real-time monitoring and fault detection of the arc light channel under the control of the control unit, so that whether the arc light channel has a fault can be judged in time, the reliability of the arc light protection device is effectively improved, the protection failure risk caused by the channel fault is avoided, and real-time self-checking is realized.

Description

Technical Field

[0001] This invention relates to the field of power system protection technology, and in particular to an arc flash protection device's arc flash channel self-test circuit and method. Background Technology

[0002] Arc flash protection is an important safety protection measure in power distribution systems. It is mainly used to detect arc faults that occur inside equipment and quickly cut off the power supply when a fault occurs to prevent the accident from escalating.

[0003] Existing arc flash protection devices typically rely on fiber optic sensors or arc flash channels to detect ultraviolet light generated by arc discharge. When the device detects ultraviolet light, it triggers a protection action. However, because arc flash protection devices rarely trigger actual protection actions during long-term operation, when protection is truly needed, the sensors or signal channels may fail due to prolonged inactivity, preventing them from performing their protection functions correctly. In such cases, the protection device may be in a "false protection" state, posing a potential risk to the safety of the power distribution system.

[0004] Existing self-testing methods mostly rely on periodic manual inspections, requiring professionals to test each sensor with specialized tools. This is not only labor-intensive and inefficient, but also makes it difficult to guarantee timely fault detection. Furthermore, some devices use electrical signal detection methods, which cannot accurately reflect the transmission status of optical signals, resulting in detection blind spots.

[0005] Furthermore, for multi-channel arc flash protection devices, the lack of an effective fault diagnosis mechanism makes it difficult to accurately determine the fault location when a fault occurs in a certain channel, increasing maintenance difficulty and cost. At the same time, traditional self-testing methods often require interrupting the protection function, affecting the continuous operation of the device. Summary of the Invention

[0006] The purpose of this invention is to provide a self-testing circuit and method for the arc flash channel of an arc flash protection device, thereby providing an effective fault diagnosis mechanism for the arc flash protection device and enhancing the safety of the power distribution system.

[0007] To address the aforementioned technical problems, this invention provides a self-test circuit and method for the arc light channel of an arc light protection device. The self-test circuit for the arc light channel of the arc light protection device includes a control unit, a light source driving module, and a photoelectric detection circuit connected via an optical fiber. The light source driving module emits light of a set wavelength for self-testing under the control of the control unit. The photoelectric detection circuit receives the optical signal transmitted through the optical fiber and converts it into a voltage signal, which is then output to the control unit. The control unit compares the voltage signal with a preset threshold and determines whether a fault exists in the arc light channel based on the comparison result.

[0008] Furthermore, the light source driving module includes an optical fiber transmitter, a transistor, and multiple resistors;

[0009] The collector of the transistor is connected to the first pin of the optical fiber transmitter, the base is connected to the multiple output ports of the control unit through the multiple resistors, and the emitter is grounded.

[0010] The second pin of the fiber optic transmitter is also connected to a power supply.

[0011] Furthermore, the plurality of resistors includes a first resistor, a second resistor, and a third resistor;

[0012] The first resistor is connected between the first output port of the control unit and the base of the transistor;

[0013] The second resistor is connected between the second output port of the control unit and the base of the transistor;

[0014] The third resistor is connected between the power supply and the second pin of the optical fiber transmitter.

[0015] Furthermore, the photoelectric detection circuit includes an optical fiber receiver, an operational amplifier, and a fourth resistor;

[0016] The first pin of the fiber optic receiver is connected to the first pin of the operational amplifier, and the second pin of the fiber optic receiver is grounded;

[0017] The second pin of the operational amplifier is connected to the fourth pin of the operational amplifier, the fourth pin of the operational amplifier is also connected to the analog sampling pin of the control unit, the third pin of the operational amplifier is grounded, and the fifth pin of the operational amplifier is connected to the power supply.

[0018] One end of the fourth resistor is connected between the first pin of the optical fiber receiver and the first pin of the operational amplifier, and the other end is grounded.

[0019] Furthermore, an arc light probe is also installed on the optical fiber.

[0020] A self-test method for the arc light channel of an arc light protection device, employing the aforementioned arc light channel self-test circuit, includes:

[0021] S1. The control unit triggers a self-test function at regular intervals and outputs a control signal to the light source driver module;

[0022] S2. Select appropriate first and second resistors so that the transistor operates in amplification mode, and the light source driving module emits light of a set wavelength according to the control signal;

[0023] S3. The light of the set wavelength passes through the optical fiber and the arc probe to the photoelectric detection circuit. The photoelectric detection circuit receives the optical signal and outputs a voltage signal to the analog sampling pin of the control unit.

[0024] S4. The control unit compares the voltage signal with a preset threshold and determines whether there is a fault in the arc channel based on the comparison result.

[0025] Furthermore, S1 specifically includes:

[0026] The control unit outputs different combinations of high and low levels as control signals through the first output port and the second output port to achieve step-by-step control of the light source driving module.

[0027] Furthermore, the control signal includes:

[0028] Both the first output port and the second output port output a low level;

[0029] The first output port outputs a high level, and the second output port outputs a low level.

[0030] The first output port outputs a low level, and the second output port outputs a high level;

[0031] Both the first output port and the second output port output a high level.

[0032] Furthermore, S2 specifically includes:

[0033] When both the first output port and the second output port output a low level, the light source driving module does not emit light;

[0034] When the first output port outputs a high level and the second output port outputs a low level, the light source driving module emits light with intensity L.

[0035] When the first output port outputs a low level and the second output port outputs a high level, the light source driving module emits light with an intensity of 2 times L.

[0036] When both the first output port and the second output port output a high level, the light source driving module emits light with an intensity of 3 times L.

[0037] Furthermore, determining whether there is a fault in the arc channel based on the comparison results includes:

[0038] If the voltage signal is greater than or equal to the preset threshold, then the arc light channel is determined to be intact;

[0039] If the voltage signal is less than the preset threshold or there is no response after a timeout, it is determined that the arc light channel is faulty and corresponding processing is performed.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] The arc light protection device proposed in this invention has an arc light channel self-test circuit. Under the control of the control unit, the light source driving module emits light of a set wavelength for self-testing, and the photoelectric detection circuit receives the returned light signal and converts it into a voltage signal, realizing real-time monitoring and fault detection of the arc light channel. This enables timely detection of faults such as fiber breakage and arc light probe damage, effectively improving the reliability of the arc light protection device, avoiding the risk of protection failure due to channel faults, and achieving real-time self-testing.

[0042] Furthermore, this invention employs stepped light intensity control and infrared light of a set wavelength as a self-test signal, combined with a photoelectric detection circuit, to achieve spectral separation between the self-test signal and the actual arc light signal, avoiding mutual interference and improving the accuracy of the self-test and the reliability of the protection system. Simultaneously, the control unit can promptly issue alarm signals based on the self-test results, facilitating maintenance personnel to quickly locate and handle faults, significantly reducing maintenance costs and downtime risks. Attached Figure Description

[0043] Figure 1 This is a circuit diagram of the arc channel self-test circuit in one embodiment of the present invention;

[0044] Figure 2 This is a flowchart of an arc channel self-testing method in one embodiment of the present invention.

[0045] Reference numerals: U1, fiber optic transmitter; U2, fiber optic receiver; U3, operational amplifier; Q1, transistor; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; VCC, power supply; 1, fiber optic cable; 2, arc light probe. Detailed Implementation

[0046] Based on the teachings of this specification, those skilled in the art can form new technical solutions by combining different implementation methods without creating technical contradictions. Such variations should be considered to fall within the protection scope of this patent.

[0047] The arc light channel self-test circuit and method of an arc light protection device according to the present invention will be described in more detail below with reference to the schematic diagram, which illustrates the preferred embodiment of the present invention. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the present invention.

[0048] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0049] Example 1

[0050] like Figure 1 As shown, this embodiment proposes an arc light channel self-test circuit for an arc light protection device. The arc light channel self-test circuit of the arc light protection device includes a control unit, a light source driving module and a photoelectric detection circuit connected through an optical fiber 1.

[0051] Specifically, the light source driving module emits light of a set wavelength for self-testing under the control of the control unit; the photoelectric detection circuit receives the optical signal transmitted through the optical fiber 1 and converts it into a voltage signal, which is then output to the control unit; the control unit compares the voltage signal with a preset threshold and determines whether there is a fault in the arc channel based on the comparison result. The arc channel self-test circuit, through the light source driving module and the photoelectric detection circuit, can monitor the status of the arc channel in real time, promptly detect and respond to possible faults such as wire breakage, aging, or optical path contamination, thereby improving the reliability and safety of the arc protection device. Simultaneously, the automated self-testing process reduces reliance on manual inspection, lowers maintenance costs and workload, and improves the efficiency and accuracy of fault detection.

[0052] In practical application, the control unit can be selected as an MCU control unit with digital signal output pins and analog signal sampling pins. The MCU control unit integrates a processor core, memory, input / output ports, and various peripheral interfaces, thereby realizing complex control logic and data processing to adapt to different application requirements and changes.

[0053] In this example, the light source driving module includes an optical fiber transmitter U1, a transistor Q1, and multiple resistors. The optical fiber transmitter U1 is responsible for emitting light of a set wavelength, typically a light-emitting diode (LED) or a laser diode. The emitted wavelength can be selected as needed to adapt to different detection requirements. The transistor Q1 acts as a switching element, controlling the switching of the optical fiber transmitter U1 on and off. The transistor Q1 can be of NPN or PNP type, selected according to specific requirements. The multiple resistors are used to limit current and divide voltage, ensuring that the transistor Q1 and the optical fiber transmitter U1 operate under safe current and voltage conditions.

[0054] Specifically, the transistor Q1 is an NPN type, and its collector is connected to the first pin of the fiber optic transmitter U1. When the transistor Q1 is turned on, current can flow from the power supply VCC through the fiber optic transmitter U1 to the collector of the transistor Q1, thereby causing the fiber optic transmitter U1 to emit light. The base of the transistor Q1 is connected to multiple output ports of the control unit through multiple resistors, allowing the control unit to control the switching on and off of the transistor Q1. The emitter of the transistor Q1 is grounded, ensuring that the current flow to the fiber optic transmitter U1 is correctly controlled when the transistor Q1 is turned on. The second pin of the fiber optic transmitter U1 is also connected to the power supply VCC, providing the necessary operating voltage for the fiber optic transmitter U1 to emit light when the transistor Q1 is turned on.

[0055] In actual operation, the power supply VCC is 3.3V or 5V, which can be selected according to the needs.

[0056] Furthermore, the plurality of resistors includes a first resistor R1, a second resistor R2, and a third resistor R3.

[0057] The first resistor R1 is connected between the first output port of the control unit and the base of the transistor Q1; the second resistor R2 is connected between the second output port of the control unit and the base of the transistor Q1. The first resistor R1 limits the current flowing into the base of the transistor Q1, protecting it from excessive current damage and ensuring sufficient current to control its conduction state. The second resistor R2 also limits current and stabilizes the operating state of the transistor Q1, working in conjunction with the first resistor R1 to achieve finer current control or provide different base drive conditions.

[0058] The third resistor R3 is connected between the power supply and the second pin of the fiber optic transmitter U1 to limit the current flowing through the fiber optic transmitter U1, prevent excessive current from damaging the fiber optic transmitter U1, and ensure that the fiber optic transmitter U1 can work stably under various power conditions, thereby improving the reliability of the entire device.

[0059] In this embodiment, the photoelectric detection circuit includes an optical fiber receiver U2, an operational amplifier U3, and a fourth resistor R4. The optical fiber receiver U2 receives the optical signal returned from the optical fiber 1 and converts it into a current signal. The optical fiber receiver U2 can be a photodiode or a phototransistor. The operational amplifier U3 amplifies the current signal output by the optical fiber receiver U2, making the current signal suitable for processing by the control unit. The fourth resistor R4 samples the current signal passing through the optical fiber receiver U2 and converts it into a voltage signal for further processing by the operational amplifier U3. It also helps to match the output impedance of the optical fiber receiver U2 with the input impedance of the operational amplifier U3, reducing signal reflection and improving signal transmission efficiency.

[0060] The first pin of the fiber optic receiver U2 is connected to the first pin of the operational amplifier U3, allowing the current signal output by the fiber optic receiver U2 to be directly input to the first pin of the operational amplifier U3, which is the inverting input (usually marked "-"), for signal amplification. The second pin of the fiber optic receiver U2 is grounded, providing a stable reference voltage for the fiber optic receiver U2 to operate normally, while also reducing noise and interference.

[0061] The second and fourth pins of operational amplifier U3 are connected to form a negative feedback loop, which helps stabilize the gain of operational amplifier U3 and improve its linearity. The fourth pin of operational amplifier U3 is also connected to the analog sampling pin of the control unit, allowing the amplified voltage signal output from operational amplifier U3 to be directly input to the analog input terminal of the control unit for further analysis and processing. The analog sampling pin is linearly proportional to the light intensity; the magnitude of the analog signal can be converted into the amplitude of the light intensity signal for easy subsequent judgment. The third pin of operational amplifier U3 is grounded, providing a stable reference voltage for normal operation and reducing noise and interference. The fifth pin of operational amplifier U3 is connected to the power supply, providing the necessary operating voltage for signal amplification.

[0062] One end of the fourth resistor R4 is connected between the first pin of the fiber optic receiver U2 and the first pin of the operational amplifier U3, and the other end is grounded. The current signal flowing through the fiber optic receiver U2 is sampled by the fourth resistor R4 to obtain a voltage signal, which is convenient for subsequent processing.

[0063] In this embodiment, an arc detector 2 is also provided on the optical fiber 1. The arc detector 2 can detect the strong light radiation generated by the arc fault, especially in the ultraviolet light region, thereby more accurately locating the location of the arc fault, reducing the harm to personnel and equipment caused by the arc fault, and improving the safety of the power distribution system.

[0064] Example 2

[0065] like Figure 2 As shown, this second embodiment, based on the first embodiment, proposes a self-test method for the arc channel of an arc protection device, specifically including:

[0066] S1. The control unit triggers the self-test function at regular intervals and outputs control signals to the light source drive module, so that the self-test process is automatically executed at predetermined time intervals without manual intervention, thereby improving the timeliness and reliability of the test.

[0067] S2. Select appropriate first resistor R1 and second resistor R2 to ensure that transistor Q1 operates in amplification mode. The light source driving module emits light of a set wavelength according to the control signal. The light of the set wavelength is used to simulate actual arc fault signals in order to test the response capability of the photoelectric detection circuit.

[0068] S3. The light of the set wavelength travels through optical fiber 1 and arc probe 2 to the photoelectric detection circuit. The photoelectric detection circuit receives the optical signal and outputs a voltage signal to the analog sampling pin of the control unit. This simulates the actual optical signal transmission process to verify the integrity of the arc channel and the normal functioning of the photoelectric detection circuit.

[0069] S4. The control unit compares the voltage signal with a preset threshold and determines whether the arc light channel is faulty based on the comparison result. By comparing the voltage signal with the preset threshold, it can be determined whether the arc light channel is intact or faulty.

[0070] The arc light channel self-testing method effectively improves the performance of the arc light protection device and the safety of the power distribution system through an automated testing process. By monitoring the integrity of the arc light sensor and signal transmission link in real time, it can detect faults in a timely manner, thus ensuring the stable operation of the power distribution system.

[0071] In this embodiment, S1 specifically includes:

[0072] The control unit outputs different combinations of high and low levels as control signals through the first and second output ports to achieve stepped control of the light source driving module. This stepped control method provides high flexibility and control capability for the self-testing of the arc protection device, enabling the device to adjust the output of the light source according to different test requirements and environmental conditions. This not only improves the accuracy and reliability of self-testing but also helps optimize energy use and enhance the device's fault diagnosis capability.

[0073] Specifically, the control signals include:

[0074] Both the first output port and the second output port output a low level.

[0075] The first output port outputs a high level, and the second output port outputs a low level.

[0076] The first output port outputs a low level, and the second output port outputs a high level;

[0077] Both the first output port and the second output port output a high level.

[0078] In this embodiment, S2 specifically includes:

[0079] When both the first output port and the second output port output a low level, the light source driving module does not emit light, so that the light source driving module does not emit light or is in the lowest power state, which is used to test the response of the arc light channel in the absence of light signal, or to save energy when it is not necessary to emit light.

[0080] When the first output port outputs a high level and the second output port outputs a low level, the light source driving module emits light of intensity L, controlling the light source driving module to emit light at a medium power, providing sufficient light signal to activate the photoelectric detection circuit, but not too strong, so that the response of the arc light channel under medium signal conditions can be tested.

[0081] When the first output port outputs a low level and the second output port outputs a high level, the light source driving module emits light with an intensity of 2 times L. This setting enables the light source driving module to emit light at a different medium power, which can be used for different test conditions or as redundant control, so that the device can work normally under different configurations.

[0082] When both the first output port and the second output port output a high level, the light source driving module emits light with an intensity of 3 times L, causing the light source driving module to emit light at maximum power. This is used for self-test operations that require strong light signals, or to simulate the strongest arc fault signal under set test conditions.

[0083] In this embodiment, the light with the set wavelength is infrared light with a wavelength of 850nm. 850nm infrared light has good penetrating power and can be effectively transmitted through optical fibers. Even if there is some contamination or aging in the optical fiber, the integrity of the optical signal can be maintained relatively well. Furthermore, the infrared light does not overlap with the visible spectrum range of natural light (400-700nm), therefore, it is less affected by natural light interference during the self-test process, improving the accuracy of the self-test.

[0084] In this embodiment, determining whether there is a fault in the arc channel based on the comparison result includes:

[0085] If the voltage signal is greater than or equal to the preset threshold, the arc light channel is considered to be intact. When the optical signal received by the photoelectric detection circuit is strong enough, the converted voltage signal will be higher than the preset threshold, indicating that the arc light channel can transmit optical signals normally without obvious attenuation or blockage. Therefore, the arc light channel can be considered to be in good condition.

[0086] If the voltage signal is less than the preset threshold or there is no response after a timeout, it is determined that there is a fault in the arc light channel, which is determined to be a broken optical fiber or a sensor failure. The fault is then reported to the corresponding processing system for appropriate handling.

[0087] In summary, the arc light channel self-test circuit of the arc light protection device proposed in this invention, under the control of the control unit, emits light of a set wavelength from the light source driving module for self-testing, and uses the photoelectric detection circuit to receive the returned light signal and convert it into a voltage signal, thereby realizing real-time monitoring and fault detection of the arc light channel. This enables timely detection of faults such as fiber breakage and arc light probe damage, effectively improving the reliability of the arc light protection device, avoiding the risk of protection failure due to channel faults, and achieving real-time self-testing.

[0088] Furthermore, this invention employs stepped light intensity control and infrared light of a set wavelength as a self-test signal, combined with a photoelectric detection circuit, to achieve spectral separation between the self-test signal and the actual arc light signal, avoiding mutual interference and improving the accuracy of the self-test and the reliability of the protection system. Simultaneously, the control unit can promptly issue alarm signals based on the self-test results, facilitating maintenance personnel to quickly locate and handle faults, significantly reducing maintenance costs and downtime risks.

[0089] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A self-test circuit for the arc light channel of an arc light protection device, characterized in that, It includes a control unit, and a light source drive module and a photoelectric detection circuit connected via optical fiber; The light source driving module is used to emit light of a set wavelength for self-testing under the control of the control unit; the photoelectric detection circuit is used to receive the optical signal transmitted through the optical fiber and convert it into a voltage signal and output it to the control unit; the control unit compares the voltage signal with a preset threshold and determines whether there is a fault in the arc light channel based on the comparison result.

2. The arc light channel self-test circuit of the arc light protection device as described in claim 1, characterized in that, The light source driving module includes an optical fiber transmitter, a transistor, and multiple resistors; The collector of the transistor is connected to the first pin of the optical fiber transmitter, the base is connected to the multiple output ports of the control unit through the multiple resistors, and the emitter is grounded. The second pin of the fiber optic transmitter is also connected to a power supply.

3. The arc light channel self-test circuit of the arc light protection device as described in claim 2, characterized in that, The plurality of resistors includes a first resistor, a second resistor, and a third resistor; The first resistor is connected between the first output port of the control unit and the base of the transistor; The second resistor is connected between the second output port of the control unit and the base of the transistor; The third resistor is connected between the power supply and the second pin of the optical fiber transmitter.

4. The arc light channel self-test circuit of the arc light protection device as described in claim 1, characterized in that, The photoelectric detection circuit includes an optical fiber receiver, an operational amplifier, and a fourth resistor; The first pin of the fiber optic receiver is connected to the first pin of the operational amplifier, and the second pin of the fiber optic receiver is grounded; The second pin of the operational amplifier is connected to the fourth pin of the operational amplifier, the fourth pin of the operational amplifier is also connected to the analog sampling pin of the control unit, the third pin of the operational amplifier is grounded, and the fifth pin of the operational amplifier is connected to the power supply. One end of the fourth resistor is connected between the first pin of the optical fiber receiver and the first pin of the operational amplifier, and the other end is grounded.

5. The arc light channel self-test circuit of the arc light protection device as described in claim 1, characterized in that, An arc light probe is also installed on the optical fiber.

6. A method for self-testing the arc light channel of an arc light protection device, employing the arc light channel self-testing circuit according to any one of claims 1-5, characterized in that, include: S1. The control unit triggers a self-test function at regular intervals and outputs a control signal to the light source driver module; S2. Select appropriate first and second resistors so that the transistor operates in amplification mode, and the light source driving module emits light of a set wavelength according to the control signal; S3. The light of the set wavelength passes through the optical fiber and the arc probe to the photoelectric detection circuit. The photoelectric detection circuit receives the optical signal and outputs a voltage signal to the analog sampling pin of the control unit. S4. The control unit compares the voltage signal with a preset threshold and determines whether there is a fault in the arc channel based on the comparison result.

7. The arc light channel self-test method of the arc light protection device as described in claim 6, characterized in that, S1 specifically includes: The control unit outputs different combinations of high and low levels as control signals through the first output port and the second output port to achieve step-by-step control of the light source driving module.

8. The arc light channel self-test method of the arc light protection device as described in claim 7, characterized in that, The control signals include: Both the first output port and the second output port output a low level; The first output port outputs a high level, and the second output port outputs a low level. The first output port outputs a low level, and the second output port outputs a high level; Both the first output port and the second output port output a high level.

9. The arc light channel self-test method of the arc light protection device as described in claim 8, characterized in that, S2 specifically includes: When both the first output port and the second output port output a low level, the light source driving module does not emit light; When the first output port outputs a high level and the second output port outputs a low level, the light source driving module emits light with intensity L. When the first output port outputs a low level and the second output port outputs a high level, the light source driving module emits light with an intensity of 2 times L. When both the first output port and the second output port output a high level, the light source driving module emits light with an intensity of 3 times L.

10. The arc light channel self-test method of the arc light protection device as described in claim 6, characterized in that, The step of determining whether the arc channel is faulty based on the comparison results includes: If the voltage signal is greater than or equal to the preset threshold, then the arc light channel is determined to be intact; If the voltage signal is less than the preset threshold or there is no response after a timeout, it is determined that the arc light channel is faulty and corresponding processing is performed.

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