Low-voltage transformer area electrical short circuit arc detection processing method and system

Abstract

The invention relates to the technical field of circuit detection, and discloses a low-voltage transformer area electrical short circuit arc detection processing method and system. According to the invention, aiming at the condition that the current abnormity duration is relatively long, even if the voltage and the frequency spectrum do not display typical arc signals, the abnormal conduction state can be confirmed by strictly comparing the time when the current exceeds the normal range, so that misjudgment caused by instantaneous interference is avoided. It is worthy of noticing that due to the fact that the temperature sensor has the problems of response lag and uneven area distribution when monitoring the electric arc, when continuous high current does not have sudden temperature increase and voltage and frequency spectrum abnormity, it is directly judged that the electric arc is not generated, and the processing strategy effectively prevents unnecessary protection actions caused by temperature errors. The advantages of various sensing data are fully integrated, and through a layer-by-layer verification and mutual evidence mode, the short circuit hidden danger can be found in time, and the reliability of fault judgment and the overall safety of the system can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit detection, and in particular to a method and system for detecting and processing electrical short circuit arcs in a low-voltage station area. Background Art

[0002] The low-voltage substation is the area in the power distribution system responsible for the management and distribution of low-voltage electricity. It is mainly responsible for distributing the low-voltage electricity output by the transformer to the end users in a stable and reliable manner through a series of distribution equipment. Its main components include low-voltage switchgear, distribution busbars, outgoing line devices, and supporting protection, automation control and monitoring systems. The low-voltage substation is usually equipped with an incoming line cabinet to receive power from the substation or distribution transformer; then the power is distributed to various users or different areas through the busbars and outgoing line cabinets to achieve load balancing. At the same time, the low-voltage substation is also equipped with the necessary automation system to monitor the operating status of the equipment in real time, quickly detect anomalies and faults, and ensure power supply safety and quality. It is an important link in the power system that directly supplies residential and industrial users.

[0003] Low-voltage substations are critical nodes in the power distribution system, with dense equipment and complex power supply environments. Electrical short-circuit failures are easily accompanied by arc flashes. The high temperature, strong light, and electromagnetic interference generated by arc flashes can not only severely damage the insulation and structure of equipment but can also cause fires or explosions, jeopardizing the overall stable operation of the power supply system and the safety of personnel. By monitoring electrical short-circuit arcs in real time, the detection system can quickly detect abnormal conditions in the early stages of a fault and issue an early warning, prompting operations and maintenance personnel to take timely isolation and repair measures, reducing the risk of the accident spreading. Summary of the Invention

[0004] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method and system for detecting and processing electrical short circuits and arcs in low-voltage substations, so as to detect electrical short circuits and arcs.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: A method for detecting and processing electrical short circuit arcs in a low-voltage substation, comprising: step one, installing a current transformer in the circuit to monitor the current in the circuit, and at the same time, obtaining the working current of the normal operation of the circuit, and setting the current threshold range according to the normal current fluctuation; step two, obtaining the real-time current in the circuit, comparing the real-time current with the current threshold range, if the real-time current falls within the current threshold range, it means that the fluctuation is normal, and the circuit is normal; if the real-time current is less than the minimum value of the current threshold range, it means that the current is lower than the normal value, and there are other faults in the circuit besides short circuit; if the real-time current is greater than the current threshold range, it means that the current is lower than the normal value, and there are other faults in the circuit besides short circuit; The maximum value of the range indicates a surge in current, and a short circuit is preliminarily determined in the circuit; step three, obtaining the real-time voltage through the voltage sensor, and setting the voltage threshold range according to normal voltage fluctuations; step four, comparing the real-time voltage with the voltage threshold range to determine whether the real-time voltage is lower than the minimum value of the voltage threshold range. If the real-time voltage is lower than the minimum value of the voltage threshold range, it indicates a sudden voltage drop, and the preliminarily determined short circuit is confirmed; if the real-time voltage is not lower than the minimum value of the voltage threshold range, it indicates that the voltage has not suddenly dropped, and the preliminarily determined short circuit is not confirmed. For the preliminarily determined short circuit that is not confirmed by the voltage sudden drop, further analysis is performed through spectrum analysis to determine whether it can be confirmed.

[0006] In some embodiments, when a short circuit that has been preliminarily identified is confirmed, the real-time temperature in the circuit is obtained through a temperature sensor. At the same time, a time period is set to obtain the average temperature in the circuit over the past time period, and a temperature threshold range is set based on a normal temperature fluctuation range. The real-time temperature is compared with the temperature threshold range, and whether an arc is generated is determined based on the comparison result.

[0007] In some embodiments, if the real-time temperature is higher than the maximum value of the temperature threshold range, it means that the temperature in the circuit has risen sharply, and it is determined that an arc has been generated in the short-circuit circuit; if the real-time temperature falls within the temperature threshold range or is less than the minimum value of the temperature range threshold, it means that the temperature in the circuit has not increased, and it is determined that no arc has been generated in the short-circuit circuit.

[0008] In some embodiments, during spectrum analysis, the instantaneous waveform of the voltage is captured, and the time domain signal is converted into the frequency domain after transformation to obtain a spectrum diagram of the voltage. The spectrum diagram is compared with the spectrum data under normal conditions, and different responses are obtained based on the comparison results.

[0009] In some embodiments, if there is a sudden increase in energy in the high frequency region of the spectrum graph, the short circuit phenomenon has been confirmed by the spectrum characteristics; if there is no sudden increase in energy in the high frequency region of the spectrum graph, the short circuit phenomenon has not been confirmed.

[0010] In some embodiments, if the short circuit phenomenon cannot be supported by voltage and spectrum characteristics, the time during which the real-time current exceeds the maximum value of the current threshold range is obtained. At the same time, a time-exceeding threshold is set, and the time-exceeding threshold is compared with the time-exceeding threshold. Different responses are obtained based on the comparison results.

[0011] In some embodiments, if the exceeding time is less than or equal to the exceeding time threshold, it means that the real-time current surge is short, and the current surge is determined to be caused by a sudden load change or a switch action switching; if the real-time current surge is long, even if the voltage and spectrum characteristics cannot prove a short circuit, it is still determined that a short circuit occurs in the circuit.

[0012] In some embodiments, when a current surge is initially determined to be a short circuit, but the initial determination cannot be supported by voltage and spectrum characteristics, but the current surge is judged to have lasted for a long time by the timeout period, the temperature is no longer used to determine whether an arc is generated, and it is directly determined that no arc is generated.

[0013] The present invention further provides a low-voltage substation electrical short circuit arc detection and processing system, which is used to execute the above-mentioned method, including: a current acquisition module, which is used to install a current transformer in the circuit to monitor the current in the circuit, and at the same time, obtain the working current of the normal operation of the circuit, and set the current threshold range according to the normal current fluctuation; a current judgment module, which is used to obtain the real-time current in the circuit, compare the real-time current with the current threshold range, if the real-time current falls within the current threshold range, it means that the fluctuation is normal, and the circuit is normal; if the real-time current is less than the minimum value of the current threshold range, it means that the current is lower than the normal value, and the circuit has other faults besides short circuit; if the real-time current is greater than the current threshold range, it means that the current is lower than the normal value, and the circuit has other faults besides short circuit. The maximum value of the voltage indicates a surge in current, and a short circuit is preliminarily determined in the circuit; a voltage acquisition module is used to obtain the real-time voltage through a voltage sensor and set a voltage threshold range according to normal voltage fluctuations; a voltage judgment module is used to compare the real-time voltage with the voltage threshold range to determine whether the real-time voltage is lower than the minimum value of the voltage threshold range. If the real-time voltage is lower than the minimum value of the voltage threshold range, it indicates a sudden voltage drop, and the preliminarily determined circuit short circuit is confirmed; if the real-time voltage is not lower than the minimum value of the voltage threshold range, it indicates that the voltage has not suddenly dropped, and the preliminarily determined circuit short circuit is not confirmed. For the preliminarily determined circuit short circuit that is not confirmed by the voltage sudden drop, further analysis is performed through spectrum analysis to determine whether it can be confirmed.

[0014] The present invention further provides a computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the above-mentioned low-voltage substation electrical short circuit arc detection and processing method.

[0015] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0016] First, this invention achieves rapid and accurate location and resolution of electrical faults in low-voltage substations by integrating multi-dimensional detection methods, including current, voltage, spectrum, and temperature. Under real-time monitoring by current transformers, a normal current fluctuation range is established based on historical data and equipment parameters. When the actual current exceeds this range, a preliminary fault probability assessment can be quickly made, distinguishing between sudden load changes, switching actuation, and short-circuit faults.

[0017] Secondly, the present invention collects real-time voltage data through a voltage sensor, and compares the current surge with the voltage drop to see if they reach a preset threshold, thereby providing a second level of evidence and greatly improving the accuracy of fault judgment; when the voltage does not drop significantly, a high-speed data acquisition instrument is used to capture the instantaneous waveform, which is converted to the frequency domain through fast Fourier transform, and the high-frequency noise characteristics are analyzed to determine whether there are short-circuit-specific phenomena such as spark discharge.

[0018] Thirdly, for situations where the current anomaly lasts for a long time, the present invention can confirm the abnormal conduction state by strictly comparing the time when the current exceeds the normal range, even if the voltage and spectrum do not show a typical arc signal, thereby avoiding misjudgment due to instantaneous interference. It is worth noting that since temperature sensors have response lags and uneven regional distribution when monitoring arcs, when a continuous high current is not accompanied by a sharp increase in temperature and abnormal voltage and spectrum, it is directly judged that no arc has occurred. This processing strategy effectively prevents unnecessary protection actions caused by temperature errors. This fully integrates the advantages of multiple sensor data, and through layer-by-layer verification and mutual support, it can not only detect short-circuit hazards in a timely manner, but also significantly improve the credibility of fault judgment and the overall safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the method steps of the present invention;

[0020] Figure 2 Schematic diagram of the system module of the present invention. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0023] The present invention provides a low voltage area electrical short circuit arc detection and processing method, such as Figure 1 and Figure 2 Shown, including:

[0024] The first step is to install current transformers in the low-voltage substation circuit system to monitor the circuit current in real time. Simultaneously, the operating current during normal operation is obtained based on historical records and device parameters. A normal current fluctuation range is set for the operating current, and a current threshold range is set based on this current fluctuation range. Current fluctuations within this threshold range are considered normal.

[0025] The second step is to obtain the real-time current in the circuit, compare the real-time current with the current threshold range, and formulate different responses based on the comparison results. If the real-time current falls within the current threshold range, it means that the fluctuation of the operating current is within the normal range. In this case, the circuit is normal. If the real-time current is less than the minimum value of the current threshold range, it means that the operating current is lower than normal. In this case, the circuit has other faults besides short circuits, such as open circuits, poor contact, and reduced load. For other faults besides short circuits, further detection and judgment are carried out, and targeted measures are taken. If the real-time current is greater than the maximum value of the current threshold range, it means that the operating current has increased significantly. In this case, it is preliminarily determined that a short circuit has occurred in the circuit, and the short circuit judgment is further supported by monitoring the voltage.

[0026] The third step is to use a voltage sensor to obtain the real-time voltage in the circuit. A voltage fluctuation range is set, and a voltage threshold range is set based on the voltage fluctuation range. The real-time voltage is compared with the voltage threshold range to determine whether it is below the minimum value of the voltage threshold range. If the real-time voltage is below the minimum value of the voltage threshold range, it indicates that the real-time current in the circuit has suddenly increased while the real-time voltage has suddenly dropped. These two factors corroborate each other, and in this case, a short circuit is determined. Once a short circuit is confirmed, the temperature in the circuit is obtained using a temperature sensor and recorded as the real-time temperature. A time period is set to obtain the average temperature of the circuit over the past period, and a reasonable temperature fluctuation range is set. A temperature threshold range is set based on the temperature fluctuation range. The real-time temperature is compared with the temperature threshold range, and different responses are determined based on the comparison results. If the real-time temperature is higher than the maximum value of the temperature threshold range, it indicates that the temperature in the circuit has increased significantly. In this case, an arc is determined to have occurred in the short circuit. If the real-time temperature falls within the temperature threshold range or is lower than the minimum value of the temperature threshold range, it indicates that the temperature in the circuit has not increased. In this case, no arc is determined to have occurred in the short circuit. If the real-time voltage is not lower than the minimum value of the voltage threshold range, it means that when the real-time current in the circuit suddenly increases, the real-time voltage does not suddenly drop. The short circuit determined by the current cannot be supported by the voltage. In this case, spectrum analysis is used to determine whether the short circuit initially identified can be supported.

[0027] For example, after arranging current transformers in the low-voltage substation, historical data is used to determine that the normal operating current is 50A±5A, and the current threshold range is set to 45~55A. When the real-time current is stable within this range, it is considered normal. If the real-time current jumps to 80A (exceeding the upper limit), a short circuit fault is initially suspected. At this time, the real-time voltage collected by the voltage sensor is 190V. Assuming that the set voltage threshold range is 215V-225V, 190V is lower than the minimum value of 215V. The two confirm each other and confirm the short circuit. Further, on the premise of confirming the short circuit, the temperature sensor displays a real-time temperature of 65℃. Assuming that the set temperature threshold range is 30-50℃, 65℃ is greater than the maximum value of 50℃, and it is judged that an arc has occurred in the short-circuit circuit. On the contrary, if the real-time voltage does not drop below 215V, spectrum analysis is required to determine whether it is a real short circuit fault.

[0028] When the real-time voltage does not fall below the minimum voltage threshold, a high-speed data acquisition device is used to capture the instantaneous voltage waveform. Fast Fourier transform (FFT) is used to convert the time-domain signal to the frequency domain, resulting in a voltage spectrum. This spectrum is then compared with the spectrum data under normal conditions, and different responses are determined based on the comparison results. If there is a significant energy surge in the high-frequency region of the spectrum, the spectral characteristics confirm a short circuit. If there is no significant energy surge in the high-frequency region of the spectrum, the short circuit is not confirmed. Under normal operating conditions, the voltage signal is primarily concentrated near 50Hz or 60Hz and its lower harmonics. The noise amplitude in high-frequency bands, such as those above 1kHz, is typically low. However, when a short circuit occurs, even if the overall voltage amplitude does not change significantly, abnormal high-frequency noise and harmonics generated at the short circuit due to spark discharges or switching surges can significantly increase the peak amplitude in the 1kHz-3kHz or even higher frequency range. For example, under normal operating conditions, the instantaneous voltage waveform is captured by a high-speed data acquisition instrument at a sampling rate of 20kHz. After FFT transformation, the voltage signal is normally concentrated around 50Hz, and the noise amplitude in the frequency band above 1kHz is usually around 5mV. When the real-time voltage is not lower than the set minimum value of 215V, by comparing the spectrum diagram, if the noise amplitude is observed to jump significantly to above 20mV in the 1kHz~3kHz region, for example, 25mV is measured, it indicates that the high-frequency anomaly is caused by spark discharge or switch impact at the short circuit, which confirms the short circuit phenomenon. On the contrary, if the amplitude of the high-frequency band remains in the range of 5~10mV, it means that there is no abnormal high-frequency energy surge, and the short circuit phenomenon cannot be confirmed by the spectrum characteristics.

[0029] If a short circuit cannot be confirmed by voltage and spectral characteristics, the duration that the real-time current exceeds the maximum value of the current threshold range is obtained. A time-of-exceedance threshold is also set and compared with the time-of-exceedance threshold. Different responses are determined based on the comparison result. If the time-of-exceedance threshold is less than or equal to the time-of-exceedance threshold, the real-time current surge is short-lived. In this case, the current surge is determined to be caused by a sudden load change or a switching operation. If the real-time current surge lasts for a long time, a short circuit is still determined even if neither the real-time voltage nor the spectral characteristics confirm a short circuit. This is because the persistent current-threshold-exceedance phenomenon, even when neither the real-time voltage nor the spectral characteristics show abnormalities, is highly reliable. While a sudden current surge can be caused by a sudden load change or a switching operation, if the current increase is brief, it may be a transient fluctuation. However, if the current remains outside the normal range for a long time, even if the voltage does not drop significantly and the spectrum does not capture high-frequency anomalies, it still indicates an abnormal conduction state within the circuit. Some short-circuit faults may not immediately cause voltage drops or high-frequency noise changes in the early stages. For example, due to poor contact, reduced internal impedance, or a partially faulty circuit, the voltage waveform may remain relatively stable. However, persistently high currents indicate an abnormal energy transfer channel in the circuit. By setting a timeout threshold to filter out transient interference, if the timeout persists beyond the preset threshold, a true short-circuit risk can be determined, allowing timely protective measures to be implemented. For example, assuming the current under normal operating conditions is 50A±5A and the current threshold range is 45-55A. When the real-time current suddenly increases to 80A, based on the above example, if the voltage remains stable above 215V and the spectrum amplitude in the 1kHz-3kHz region only remains within the 5-10mV range, it is initially determined that a short circuit cannot be confirmed by the voltage and spectrum. At this time, timeout detection is introduced: the timeout threshold exceeding the maximum current threshold (55A) is set to 2 seconds. If the 80A state only lasts for 1.5 seconds, it can be attributed to a sudden load change or a brief interference caused by the switching action. Conversely, if the 80A state lasts for more than 2 seconds, although the voltage and spectrum do not show obvious abnormalities, the continuous high current may indicate an abnormal conduction channel in the circuit, such as poor contact or reduced internal impedance, and therefore a short circuit must still be determined.

[0030] When a current surge is initially determined to be a short circuit, but the initial judgment cannot be supported by the voltage and spectrum characteristics, but the timeout period determines that the current surge lasts for a long time, the temperature is no longer used to determine whether an arc has occurred, and it is directly determined that no arc has occurred. This is because when the current surge is initially determined to be a short circuit, but the voltage and spectrum characteristics fail to show typical short circuit or arc signals, if the current continues to exceed the threshold for a long time as determined by the timeout period, it means that the abnormality in the circuit is persistent, but the abnormality here is not accompanied by a sudden drop in voltage and a sharp increase in high-frequency noise, which are usually the characteristic signals that must appear in arc discharge; in other words, a real arc phenomenon will not only increase the current abnormality, but also cause a rapid rise in local temperature, a significant voltage drop, and a surge in the high-energy noise band in the spectrum, while the current detected situation is only a persistent high current without Other evidence suggests that temperature changes detected by temperature sensors may only reflect the steady-state thermal effects of normal conduction, rather than the rapid energy release caused by an arc. Furthermore, due to the hysteresis and regional unevenness of temperature response, the actual discharge may not be immediately reflected in the early stages of a short-circuit fault. Relying on temperature data to determine whether an arc has occurred is susceptible to external interference and errors, leading to misjudgment. Therefore, to improve the accuracy of fault diagnosis, if the current exceeds the normal value for a long time and the voltage and spectrum do not show the drastic changes expected for an arc, it can be directly determined that no arc has formed. For example, under normal operating conditions, the current is 50 ± 5A, the voltage is maintained at 220 V ± 5V, and the spectrum is primarily concentrated between 50 and 60 Hz, with no significant high-frequency noise. If the current surges to 90A and remains above the set threshold of 55A for 3 seconds, while the voltage only slightly drops to around 218V and the spectrum lacks high-energy noise above 1kHz, a preliminary short-circuit risk can be determined. Since arc faults are usually accompanied by a sharp drop in voltage, a surge in high-frequency noise, and a rapid rise in temperature, and the current detected situation only manifests as a continuous high current and lacks the above typical arc signals, it can be directly determined that no arc has occurred in this fault state.

[0031] In summary, the present invention adopts a variety of real-time monitoring methods such as current, voltage, spectrum and temperature, and realizes the rapid judgment and processing of electrical short circuits and arc faults in low-voltage substations by establishing thresholds and fluctuation ranges based on historical records and equipment parameters. First, a current transformer is installed in the circuit to collect current data in real time, and the current threshold is set according to the fluctuation range of normal working conditions (for example, 50A±5A). If the real-time current is within this range, the circuit is considered to be working normally; when the current is lower than the lower limit of the threshold, it indicates that there may be faults such as open circuit, poor contact or load reduction, and further detection is required; and when the current exceeds the upper limit of the threshold, a short circuit fault is initially suspected, and the next step of detection is initiated. Subsequently, the real-time voltage is monitored using a voltage sensor, and a reasonable voltage fluctuation range is set, such as maintaining it at 220V±5V. If the voltage drops sharply (for example, to far below 215V), this will corroborate the current anomaly and confirm a short circuit fault. On this basis, the temperature sensor is used to monitor local temperature changes, comparing the average temperature over a period of time with the set temperature threshold to determine whether an arc has occurred, as an arc can cause the temperature to rise rapidly and the local temperature to significantly exceed the normal range. If the real-time voltage does not drop to the preset critical value, the instantaneous voltage waveform is captured with a high-speed data acquisition instrument, and the spectrum data is obtained using a fast Fourier transform (FFT). The reliability of the short circuit is determined by comparing the normal spectrum with the abnormal surge in high-frequency noise during the short circuit. To filter transient disturbances in this series of tests, the method also incorporates a timeout threshold judgment mechanism. This mechanism detects the duration that the current exceeds the normal value. If the duration is short, it may be a transient fluctuation caused by a sudden load change or switching action. Conversely, if the duration is long, even if the voltage and spectrum do not show the sharp changes characteristic of arcing, it indicates that the circuit is in an abnormal conduction state. In this case, the absence of an arc can be directly determined, thus avoiding misjudgments caused by temperature response delays. Overall, this detection and processing solution achieves accurate identification of electrical short-circuit faults and arcing phenomena in low-voltage substations through multi-sensor data fusion.

[0032] In the embodiments disclosed herein, the processes described above with reference to the flowcharts can be implemented as computer software programs. The embodiments disclosed herein include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for executing the method illustrated in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication component and / or installed from removable media. When the computer program is executed by a central processing unit, the functions defined in the methods of this application are performed. It should be noted that the computer-readable medium referred to herein can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or components, or any combination thereof. More specific examples of computer-readable storage media can include, but are not limited to, an electrical connection having one or more wire segments, a portable computer disk, a hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. Furthermore, in this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, electrical, optical, RF, or any suitable combination thereof.

[0033] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of the systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or portion of code that contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the boxes can also occur in an order different from that marked in the accompanying drawings. For example, two boxes shown in succession can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, as well as combinations of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified functions or operations, or can be implemented using a combination of dedicated hardware and computer instructions.

[0034] Those skilled in the art should understand that the above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered by the scope of protection of the present application.

Claims

1. A method for detecting and processing electrical short circuit arcs in a low voltage substation, characterized in that: include: Step 1: Install a current transformer in the circuit to monitor the current in the circuit, obtain the normal operating current of the circuit, and set the current threshold range according to the normal current fluctuation; Step 2: Obtain the real-time current in the circuit and compare the real-time current with the current threshold range. If the real-time current falls within the current threshold range, it means that the fluctuation is normal and the circuit is normal. If the real-time current is less than the minimum value of the current threshold range, it means that the current is lower than the normal value, and there is a fault other than a short circuit in the circuit; if the real-time current is greater than the maximum value of the current threshold range, it means that the current surges, and it is preliminarily determined that there is a short circuit in the circuit; Step 3: Obtain real-time voltage through a voltage sensor and set a voltage threshold range based on normal voltage fluctuations; Step 4: Compare the real-time voltage with the voltage threshold range to determine whether the real-time voltage is lower than the minimum value of the voltage threshold range. If the real-time voltage is lower than the minimum value of the voltage threshold range, it indicates a voltage drop, and the initially determined circuit short circuit is confirmed. If the real-time voltage is not lower than the minimum value of the voltage threshold range, it means that the voltage has not suddenly dropped, and the initially determined circuit short circuit is not confirmed. For the initially determined circuit short circuit that is not confirmed by the voltage sudden drop, further analysis is performed through spectrum analysis to determine whether it can be confirmed.

2. The low voltage section electrical short circuit arc detection and processing method according to claim 1, characterized in that: When the short circuit that was initially identified is confirmed, the real-time temperature of the circuit is obtained through the temperature sensor. At the same time, a time period is set to obtain the average temperature of the circuit in the past time period, and the temperature threshold range is set according to the normal temperature fluctuation range. The real-time temperature is compared with the temperature threshold range, and it is determined whether an arc is generated based on the comparison result.

3. The low voltage section electrical short circuit arc detection and processing method according to claim 2, characterized in that: If the real-time temperature is higher than the maximum value of the temperature threshold range, it means that the temperature in the circuit has risen sharply, and it is determined that an arc has occurred in the short-circuit circuit; if the real-time temperature falls within the temperature threshold range or is lower than the minimum value of the temperature range threshold, it means that the temperature in the circuit has not increased, and it is determined that no arc has occurred in the short-circuit circuit.

4. The low voltage section electrical short circuit arc detection and processing method according to claim 3, characterized in that: During spectrum analysis, the instantaneous waveform of the voltage is captured, and the time domain signal is converted into the frequency domain after transformation to obtain the voltage spectrum diagram. The spectrum diagram is compared with the spectrum data under normal conditions, and different responses are obtained based on the comparison results.

5. The low voltage section electrical short circuit arc detection and processing method according to claim 4, characterized in that: If there is a sudden increase in energy in the high-frequency region of the spectrum graph, the short circuit phenomenon has been confirmed by the spectrum characteristics; if there is no sudden increase in energy in the high-frequency region of the spectrum graph, the short circuit phenomenon has not been confirmed.

6. The low voltage section electrical short circuit arc detection and processing method according to claim 5, characterized in that: If the short circuit phenomenon cannot be confirmed by the voltage and spectrum characteristics, the time when the real-time current exceeds the maximum value of the current threshold range is obtained. At the same time, the exceeding time threshold is set, and the exceeding time is compared with the exceeding time threshold. Different responses are obtained based on the comparison results.

7. The low voltage section electrical short circuit arc detection and processing method according to claim 6, characterized in that: If the exceeding time is less than or equal to the exceeding time threshold, it means that the real-time current surge is short, and the current surge is judged to be caused by a sudden load change or a switch action. If the real-time current surge is long, even if the voltage and spectrum characteristics cannot support a short circuit, it is still judged that a short circuit exists in the circuit.

8. The low voltage section electrical short circuit arc detection and processing method according to claim 7, characterized in that: When a current surge is initially determined to be a short circuit, but the initial determination cannot be supported by voltage and spectrum characteristics, but the current surge is judged to have lasted for a long time based on the timeout period, the temperature is no longer used to determine whether an arc has occurred, and it is directly determined that no arc has occurred.

9. A low-voltage substation electrical short circuit arc detection and processing system, which is used to execute the method according to any one of claims 1 to 8, characterized in that: include: A current acquisition module is used to install a current transformer in the circuit to monitor the current in the circuit. At the same time, it obtains the normal operating current of the circuit and sets the current threshold range according to normal current fluctuations; The current judgment module is used to obtain the real-time current in the circuit and compare the real-time current with the current threshold range. If the real-time current falls within the current threshold range, it means that the fluctuation is normal and the circuit is normal; If the real-time current is less than the minimum value of the current threshold range, it means that the current is lower than the normal value, and there is a fault other than a short circuit in the circuit; if the real-time current is greater than the maximum value of the current threshold range, it means that the current surges, and it is preliminarily determined that there is a short circuit in the circuit; A voltage acquisition module is used to obtain real-time voltage through a voltage sensor and set a voltage threshold range based on normal voltage fluctuations; A voltage judgment module is used to compare the real-time voltage with the voltage threshold range to determine whether the real-time voltage is lower than the minimum value of the voltage threshold range. If the real-time voltage is lower than the minimum value of the voltage threshold range, it indicates a voltage drop, and the initially determined circuit short circuit is confirmed; If the real-time voltage is not lower than the minimum value of the voltage threshold range, it means that the voltage has not suddenly dropped, and the initially determined circuit short circuit is not confirmed. For the initially determined circuit short circuit that is not confirmed by the voltage sudden drop, further analysis is performed through spectrum analysis to determine whether it can be confirmed.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement a low-voltage substation electrical short circuit arc detection and processing method as described in any one of claims 1 to 8.

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