A distribution box line monitoring device

Abstract

The application provides a distribution box line monitoring device, belonging to the technical field of distribution box monitoring, which comprises a grounding line loop, an excitation output circuit, a sampling circuit and a processing unit. The grounding line loop comprises a first connecting line and a second connecting line, and the first connecting line and the second connecting line form a closed loop. The excitation output circuit is used to provide an excitation voltage to the grounding line loop to generate a loop current on the grounding line loop. The sampling circuit is used to sample the loop current to obtain a loop sampling signal. The processing unit is used to obtain a line monitoring result of the distribution box according to the loop sampling signal. Since the grounding line loop is a closed loop connected between the first grounding end and the second grounding end, even if the second grounding end is not directly grounded, the grounding reliability of the second grounding end in the distribution box can be reflected through the resistance condition on the grounding line loop, so that the grounding condition of the second grounding end which is not directly grounded can be monitored.

Description

Technical Field

[0001] This application relates to the field of grounding monitoring technology, specifically to a distribution box line monitoring device. Background Technology

[0002] Temporary distribution boxes are required at various temporary work sites, such as construction sites, power emergency repair sites, and temporary construction sites, to ensure electrical safety. Temporary distribution boxes usually draw power from the upstream distribution box. However, due to the difficulty and high cost of directly grounding temporary distribution boxes, they are usually not directly grounded. Instead, they are grounded through a grounding wire connected to the upstream distribution box.

[0003] Currently, if it is necessary to test the grounding reliability of a distribution box, a grounding resistance tester is usually used. It uses a weak current sine wave excitation signal to test the grounding resistance of the connection between the grounding point under test and the remote grounding point and the earth to form a loop. However, the above method requires the grounding point under test to be directly grounded, which is not applicable to distribution boxes that are not directly grounded. Utility Model Content

[0004] In view of the shortcomings of the existing technology, this application provides a power distribution box line monitoring device.

[0005] Firstly, this application provides a distribution box line monitoring device, comprising: A grounding loop includes a first connecting line and a second connecting line for connecting a first grounding terminal outside the distribution box and a second grounding terminal inside the distribution box, wherein the first connecting line and the second connecting line form a closed loop; An excitation output circuit, connected to the grounding loop, is used to provide an excitation voltage to the grounding loop so as to generate a loop current in the grounding loop; A sampling circuit, connected to the grounding loop, is used to sample the loop current to obtain a loop sampling signal; The processing unit, connected to the sampling circuit, is used to obtain the line monitoring results of the distribution box based on the loop sampling signal.

[0006] Optionally, the excitation output circuit includes a voltage excitation sub-circuit and a voltage transformer; The excitation sub-circuit is used to receive a square wave signal and output a first voltage divider and a second voltage divider according to the square wave signal; The voltage transformer includes a primary coil connected to the excitation sub-circuit and used to receive the first voltage divider voltage and the second voltage divider voltage, and a secondary coil connected in series to the grounding loop to generate the excitation voltage on the secondary coil.

[0007] Optionally, the voltage excitation sub-circuit includes a first resistor, a switching transistor, and a second resistor; The switching transistor includes a control electrode connected to a first terminal of the first resistor and used to receive the square wave signal, a first electrode connected to a second terminal of the first resistor and a voltage source, and a second electrode connected to a first terminal of the second resistor and used to output the first voltage divider voltage. The second resistor also includes a second terminal for outputting the second voltage divider and grounding.

[0008] Optionally, the sampling circuit includes a current transformer and a sampling sub-circuit; The current transformer includes a primary coil connected in series with the grounding loop and used to receive the loop current, and a secondary coil connected to the sampling sub-circuit. The sampling sub-circuit is used to obtain the loop sampling signal based on the signal on the secondary coil of the current transformer.

[0009] Optionally, the sampling sub-circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, and a gating switch. The gating switch device includes a control terminal connected to the gating control signal, an input terminal connected to the third resistor, the current transformer and the processing unit, a first output terminal connected to the fourth resistor and a second output terminal connected to the fifth resistor; The third resistor is also connected to the voltage source; the fourth and fifth resistors are also connected to the sixth resistor and the processing unit; The seventh resistor includes a first terminal connected to the sixth resistor, the current transformer, and the processing unit, and a second terminal grounded.

[0010] Optionally, the processing unit includes a low-pass filter, a high-pass filter, a metering chip, and a processor; The low-pass filter is connected to the sampling circuit and is used to perform low-pass filtering on the loop sampling signal. The high-pass filter is connected to the sampling circuit and is used to perform high-pass filtering on the loop sampling signal; The metering chip is connected to the low-pass filter and the high-pass filter, and is used to sample the loop sampling signal after the high-pass filtering and the loop sampling signal after the low-pass filtering, respectively, to obtain the power frequency filtered signal and the excitation filtered signal. The processor, connected to the metering chip, is used to obtain the line monitoring results based on the power frequency filter signal and the excitation filter signal.

[0011] Optionally, the high-pass filter includes an eighth resistor and a first capacitor; The first capacitor includes a first terminal connected to the sampling circuit and a second terminal connected to the metering chip and the eighth resistor; The eighth resistor includes a first end connected to the first capacitor and a second end connected to the sampling circuit.

[0012] Optionally, the low-pass filter includes a second capacitor and a ninth resistor; The ninth resistor includes a first terminal connected to the sampling circuit and a second terminal connected to the second capacitor and the metering chip; The second capacitor includes a first terminal connected to the ninth resistor and a second terminal connected to the sampling circuit.

[0013] Optionally, it also includes a enclosure detection circuit for sampling the voltage between the enclosure of the distribution box and the grounding loop to obtain the enclosure voltage value; The enclosure detection circuit includes a measuring current transformer and a tenth resistor; The measuring transformer includes a primary side first terminal connected to the outer casing of the distribution box, a primary side second terminal connected to the grounding loop, a secondary side first terminal connected to the tenth resistor and the processing unit, and a secondary side second terminal connected to the second terminal of the tenth resistor and ground. The secondary side of the measuring transformer is used to output the box voltage value. The processing unit is also used to obtain the line monitoring results based on the voltage value of the enclosure.

[0014] Optionally, it also includes a ground detection circuit for sampling the voltage between any phase voltage of the transformer in the distribution box and the voltage of the grounding loop to obtain the ground voltage value; The ground detection circuit includes a diode, an optocoupler, and an eleventh resistor. The diode includes an anode for receiving any one of the phase voltages and a cathode connected to the optocoupler; The optocoupler includes an anode connected to the diode, a cathode connected to the grounding loop, a collector connected to the voltage source, and an emitter connected to the eleventh resistor and the processing unit and used to output the voltage value to ground; the eleventh resistor includes a first end connected to the optocoupler and a second end grounded. The processing unit is also used to obtain the line monitoring results based on the voltage value to ground.

[0015] In summary, this application provides an excitation voltage to the grounding loop through an excitation output circuit. Since the grounding loop has a certain resistance, when an excitation voltage is applied, a loop current flowing throughout the entire grounding loop is generated. Then, a sampling circuit samples the loop current to obtain a loop sampling signal. This signal characterizes the resistance of the grounding loop. Because the grounding loop is a closed loop connecting the first and second grounding terminals, even if the second grounding terminal is not directly grounded, the resistance of the grounding loop can indirectly reflect the grounding reliability of the second grounding terminal within the distribution box. Therefore, the processing unit can obtain the distribution box line monitoring results based on the loop sampling signal, and thus, for the second grounding terminal that is not directly grounded, its grounding status can be monitored. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of a method for monitoring distribution box lines in one embodiment of this application; Figure 2 This is a schematic diagram of a grounding loop in one embodiment of this application; Figure 3 This is a flowchart of a method for generating line monitoring results in one embodiment of this application; Figure 4 This is a schematic diagram of a distribution box line monitoring device in one embodiment of this application; Figure 5 This is a circuit connection diagram of the excitation output circuit in one embodiment of this application; Figure 6 This is a circuit connection diagram of the sampling circuit in one embodiment of this application; Figure 7 This is a circuit connection diagram of the processing unit in one embodiment of this application; Figure 8 This is a circuit connection diagram of the enclosure detection circuit in one embodiment of this application; Figure 9 This is a circuit connection diagram of a ground detection circuit in one embodiment of this application; Figure 10 This is a schematic diagram of an electronic device in one embodiment of this application.

[0018] Explanation of reference numerals in the attached diagram: 1. Grounding loop; 11. First connecting line; 12. Second connecting line; 2. Excitation output circuit; 21. Voltage excitation sub-circuit; 3. Sampling circuit; 31. Sampling sub-circuit; 4. Processing unit; 41. Low-pass filter; 42. High-pass filter; 43. Metering chip; 44. Processor; 5. Enclosure detection circuit; 6. Ground detection circuit. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to implement and use this application. In the following description, details are set forth for illustrative purposes. It should be understood that those skilled in the art will recognize that this application can be implemented without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid unnecessary detail that would obscure the description of this application. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0021] Firstly, such as Figure 1 As shown, in one embodiment, this application provides a method for monitoring distribution box lines, which includes steps S10-S30, and will be described in detail below.

[0022] Step S10: Provide an excitation voltage to grounding loop 1 to generate loop current in grounding loop 1.

[0023] Reference Figure 2The grounding loop 1 includes a first connecting line 11 and a second connecting line 12 for connecting a first grounding terminal outside the distribution box and a second grounding terminal inside the distribution box, wherein the first connecting line 11 and the second connecting line 12 form a closed loop.

[0024] As an example, the first grounding terminal is directly connected to the earth. The first grounding terminal can be an independent grounding point outside the distribution box, or it can be the grounding point of another distribution box outside this distribution box. For example, the first grounding terminal can be the upstream distribution box of this distribution box. If the distribution box is a three-level distribution box, then the second grounding terminal can be the grounding terminal of the three-level distribution box, and the first grounding terminal can be the grounding terminal in a two-level distribution box or a one-level distribution box.

[0025] As an example, the second grounding terminal is not directly grounded. Instead, it is connected to the first grounding terminal by a connecting wire, so that the second grounding terminal is connected to the earth through the connection and the first grounding terminal. One of the first connecting wire 11 and the second connecting wire 12 can be used directly, thus forming a closed loop: first grounding terminal - first connecting wire 11 - second grounding terminal - second connecting wire 12 - first grounding terminal.

[0026] Step S20: Sample the loop current to obtain the loop sampling signal.

[0027] As an example, since the first connecting line 11 and the second connecting line 12 form a closed loop in series, the current on the first connecting line 11 and the second connecting line 12 is equal. When an excitation voltage is provided to the grounding loop 1, the loop current generated in the grounding loop 1 is also equal everywhere. When sampling the loop current, any point on the grounding loop 1 can be selected for sampling.

[0028] Step S30: Obtain the line monitoring results of the distribution box based on the loop sampling signal.

[0029] The loop current includes the excitation current and the leakage current. The excitation current is directly generated by the excitation voltage applied to grounding loop 1. Since grounding loop 1 has a certain resistance, based on Ohm's law, applying an excitation voltage to grounding loop 1 will generate a corresponding excitation current. The leakage current occurs during the actual use of the distribution box. Due to potential insulation aging or damage in the electrical equipment, current leaks from the circuitry within the distribution box to the second grounding terminal, resulting in leakage current in grounding loop 1. Therefore, the loop sampling signal obtained by sampling the loop current can reflect both the resistance of grounding loop 1 and the leakage current in the distribution box, thus providing more accurate line monitoring results.

[0030] In the above embodiment, an excitation voltage is provided to the grounding loop 1. Since the grounding loop 1 has a certain resistance, when the excitation voltage is applied to the grounding loop 1, a loop current flowing throughout the entire grounding loop 1 is generated. Then, the loop current is sampled to obtain a loop sampling signal. The loop sampling signal can characterize the resistance of the grounding loop 1. Since the grounding loop 1 is a closed loop connecting the first grounding terminal and the second grounding terminal, even if the second grounding terminal is not directly grounded, the grounding reliability of the second grounding terminal in the distribution box can be indirectly reflected by the resistance of the grounding loop 1, thereby obtaining the distribution box line monitoring results. Furthermore, for the second grounding terminal that is not directly grounded, its grounding status can be monitored.

[0031] As one implementation of step S10, step S10 includes steps S11-S14, which will be described in detail below.

[0032] Step S11: When the grounding loop 1 is not connected to the excitation voltage, sample the current on the grounding loop 1 to obtain the loop test signal.

[0033] As an example, even when grounding loop 1 is not connected to an excitation voltage, interference signals may still exist on grounding loop 1 due to external noise or other interference factors. For instance, in the ideal case where grounding loop 1 is not connected to an excitation voltage, the current in grounding loop 1 may be zero. The loop test signal obtained by sampling the current on grounding loop 1 is used to reflect the current noise situation on grounding loop 1.

[0034] Step S12: Perform harmonic analysis on the loop test signal to obtain the noise harmonic components at each preset frequency.

[0035] As an example, the preset frequency differs from the power frequency of the power grid in the distribution box, and the significant frequency difference means that the preset frequency and the power frequency are in different frequency bands. For example, if the power frequency of the power grid is 50Hz, which is in the low-frequency band, the preset frequency could be in the high-frequency band such as 1.5kHz, 2.5kHz, or 4kHz.

[0036] Step S13: When the noise harmonic component corresponding to each preset frequency is greater than the preset noise threshold, no excitation voltage is provided, and a prompt message indicating excessive ambient noise is output.

[0037] Step S14: When the noise harmonic component corresponding to any preset frequency is less than or equal to the preset noise threshold, the target frequency is determined from each preset frequency according to the noise harmonic component, and the excitation voltage is output to the grounding loop 1 according to the target frequency.

[0038] As an example, taking preset frequencies including 1.5kHz, 2.5kHz, and 4kHz as an example, we can sequentially determine whether the noise harmonic components corresponding to 1.5kHz, 2.5kHz, and 4kHz are less than or equal to preset noise thresholds. If the noise harmonic component corresponding to 1.5kHz is less than or equal to the preset noise threshold, then 1.5kHz is taken as the target frequency. If the noise harmonic component corresponding to 1.5kHz is greater than the preset noise threshold, and the noise harmonic component corresponding to 2.5Hz is less than or equal to the preset noise threshold, then 2.5kHz is taken as the target frequency. If the noise harmonic component corresponding to 2.5kHz is greater than the preset noise threshold, and the noise harmonic component corresponding to 4Hz is less than or equal to the preset noise threshold, then 4kHz is taken as the target frequency. In this way, a target frequency with better quality can be determined, and the excitation voltage of the output target frequency is sent to ground loop 1 so that the excitation current on ground loop 1 can be accurately sampled at the target frequency.

[0039] In the above embodiment, by sampling the current on the grounding loop 1, a loop test signal is obtained. Analyzing the loop test signal allows for the determination of noise harmonic components at each preset frequency. If the noise harmonic components at each preset frequency are greater than a preset noise threshold, it indicates that the noise at each preset frequency is high. In this case, an accurate excitation current cannot be obtained at each preset frequency, and therefore no excitation voltage is output. Conversely, if the noise harmonic component corresponding to any preset frequency is less than or equal to the preset noise threshold, it indicates that at least one preset frequency has low noise. This preset frequency is then used as the target frequency, and an excitation voltage is output at the target frequency, allowing for the sampling of a more accurate excitation current.

[0040] Reference Figure 3 As one implementation of step S30, step S30 includes steps S31-S34, which will be described in detail below.

[0041] Step S31: Analyze and process the loop sampling signal to obtain the excitation sampling signal at the target frequency and the power frequency sampling signal at the power frequency corresponding to the distribution box.

[0042] Step S32: Obtain the loop resistance value of grounding loop 1 based on the excitation sampling signal.

[0043] As an example, since the frequency of the excitation signal is the target frequency, the excitation sampling signal at the target frequency can characterize the value of the excitation current generated by the excitation signal. Thus, the loop resistance value of grounding loop 1 can be calculated based on Ohm's law using the excitation sampling signal and the excitation voltage.

[0044] Step S33: Obtain the residual current value of grounding loop 1 based on the power frequency sampling signal.

[0045] Step S34: Obtain the line monitoring results of the distribution box based on the loop resistance value and the residual current value.

[0046] In the above implementation, firstly, the loop sampling signal is analyzed and processed to obtain the excitation sampling signal at the target frequency and the power frequency sampling signal. Next, based on the relationship between the excitation sampling signal and the excitation voltage, the loop resistance value of grounding loop 1 is calculated using Ohm's law. The loop resistance value reflects the electrical characteristics of grounding loop 1 itself. Simultaneously, the residual current value of grounding loop 1 is obtained from the power frequency sampling signal. This residual current value reflects whether leakage occurs and the degree of leakage. Finally, by combining the loop resistance value and the residual current value, the line monitoring results of the distribution box can be accurately obtained.

[0047] As one implementation of step S31, step S31 may include steps S311-315, which will be described in detail below.

[0048] Step S311: Perform high-pass filtering on the loop sampling signal to obtain the excitation filter signal.

[0049] As an example, a high-pass filter allows signals above a specific cutoff frequency to pass through while suppressing signals below that cutoff frequency. For instance, if the target frequency of the excitation voltage is 1.5kHz, 2.5kHz, or 4kHz, then the signal generated by the excitation voltage in the loop sampling signal will also be 1.5kHz, 2.5kHz, or 4kHz. In this case, the cutoff frequency of the high-pass filter can be set to 1kHz to separate the signal generated by the excitation voltage in the loop sampling signal, thereby obtaining a high-frequency excitation filter signal.

[0050] Step S312: Perform low-pass filtering on the loop sampling signal to obtain the power frequency filtered signal.

[0051] As an example, low-pass filtering allows signals below a specific cutoff frequency to pass through while blocking signals above that cutoff frequency. For instance, if the power grid frequency is 50Hz and the electrical equipment in the distribution box operates in this environment, power frequency current may leak into grounding loop 1. The signal generated by this leakage in the loop sampling signal will also be 50Hz. In this case, the cutoff frequency of the low-pass filter can be set to 100Hz to separate the signal generated by the leakage in the loop sampling signal, thereby obtaining a low-frequency filtered power frequency signal.

[0052] Step S313: Perform harmonic analysis on the loop sampling signal to obtain the excitation harmonic signal at the target frequency and the power frequency harmonic signal at the power frequency.

[0053] As an example, harmonic analysis can be achieved using Fourier transform, converting the time-domain loop sampled signal to the frequency domain to determine the amplitude and phase of each frequency component in the signal. For instance, harmonic analysis can be performed on the loop sampled signal with 50Hz as the fundamental frequency. If the target frequency is 1.5kHz, the excitation harmonic signal is the 30th harmonic component of the loop sampled signal; if the target frequency is 2.5kHz, the excitation harmonic signal is the 50th harmonic component; and if the target frequency is 4kHz, the excitation harmonic signal is the 80th harmonic component.

[0054] Step S314: If the difference between the excitation filter signal and the excitation harmonic signal is less than or equal to the set difference threshold, then the excitation filter signal is used as the excitation sampling signal. If the difference between the excitation filter signal and the excitation harmonic signal is greater than the difference threshold, then the excitation harmonic signal is used as the excitation sampling signal.

[0055] If the difference between the excitation filter signal and the excitation harmonic signal is less than or equal to the set difference threshold, it indicates that the excitation filter signal after high-pass filtering can well represent the characteristics of the excitation signal and is less affected by interference from other frequency band signals. Therefore, it can be directly used as the excitation sampling signal. If the difference between the excitation filter signal and the excitation harmonic signal is greater than the difference threshold, it indicates that the excitation filter signal after high-pass filtering may have an anomaly, such as a possible hardware malfunction in the high-pass filtering process. In this case, the excitation harmonic signal should be used as the excitation sampling signal.

[0056] Step S315: If the power frequency filtered signal is zero and the difference between the power frequency filtered signal and the power frequency sampled signal is greater than a preset difference, then the power frequency harmonic signal is used as the power frequency sampled signal. If the power frequency filtered signal is not zero, then the power frequency filtered signal is used as the power frequency sampled signal.

[0057] If the power frequency filtered signal is zero and the difference between the power frequency filtered signal and the power frequency sampled signal is greater than a preset difference, it indicates that there is current under the power frequency component. However, the power frequency filtered signal after low-pass filtering may be abnormal. Therefore, the power frequency harmonic signal is used as the power frequency sampled signal. If the power frequency filtered signal is not zero, it indicates that the power frequency harmonic signal can be collected normally. In this case, the more accurate power frequency filtered signal can be selected as the power frequency sampled signal.

[0058] As one implementation of step S34, step S34 may include steps S341-S343, which will be described in detail below.

[0059] Step S341: If the loop resistance value is greater than or equal to the preset resistance threshold, the line monitoring result includes a fault in the first connection line 11 or the second connection line 12.

[0060] As an example, under normal circumstances, the first connecting wire 11 and the second connecting wire 12 in grounding loop 1 have relatively stable and low resistance values. When the loop resistance value is greater than or equal to the preset resistance threshold, it indicates that the resistance of grounding loop 1 has increased abnormally. At this time, it is possible that at least one of the first connecting wire 11 and the second connecting wire 12 has a fault such as an open circuit or poor contact. Therefore, the line monitoring results determine that the fault is in the first connecting wire 11 or the second connecting wire 12.

[0061] The preset resistance threshold can be determined based on historical data and actual operating experience. For example, the preset resistance threshold can be set to 4Ω.

[0062] Step S342: If the residual current value is greater than or equal to the preset current threshold, the line monitoring results include a fault where the residual current of the distribution box exceeds the limit.

[0063] As an example, when the distribution box is operating normally, the residual current in grounding loop 1 should be within a relatively stable range. When the residual current value is greater than or equal to the preset current threshold, it indicates that current exceeding the normal range is flowing through grounding loop 1, and the distribution box may have a leakage problem. The preset current threshold can be determined based on historical data and actual operating experience; for example, the preset current threshold can be set to 300mA.

[0064] Step S343: If the loop resistance value is less than the preset resistance threshold and the residual current value is less than the preset current threshold, then the line monitoring results include no fault in the distribution box.

[0065] As a further implementation of the distribution box line monitoring method, the distribution box monitoring method also includes steps S40-S60, which will be described in detail below.

[0066] Step S40: Sample the voltage between the outer casing of the distribution box and the grounding loop 1 to obtain the box voltage value.

[0067] Step S50: If the box voltage value is greater than or equal to the preset box voltage threshold, the line monitoring results include leakage fault in the distribution box.

[0068] Step S60: If the box voltage value is less than the preset box voltage threshold, the line monitoring results include no fault in the distribution box.

[0069] As an example, under normal operating conditions, the distribution box casing is typically not energized. By sampling the voltage between the distribution box casing and grounding loop 1, the potential on grounding loop 1 can be used as a reference circuit to obtain the potential difference between the distribution box casing and grounding loop 1, thereby obtaining the box voltage value.

[0070] The preset enclosure voltage threshold can be set according to actual conditions; for example, it can be set to 50. When the enclosure voltage value is greater than or equal to the preset enclosure voltage threshold, it indicates an abnormal increase in voltage between the distribution box casing and grounding loop 1, indicating current leakage from the inside of the distribution box to the casing, thus creating a large potential difference between the casing and grounding loop 1. In this case, the line monitoring result is determined to be a leakage fault in the distribution box.

[0071] As a further implementation of the distribution box line monitoring method, the distribution box monitoring method also includes steps S70-S90, which will be described in detail below.

[0072] Step S70: Sample the voltage between any phase voltage in the transformer in the distribution box and the voltage of grounding loop 1 to obtain the voltage value to ground.

[0073] In this context, any phase voltage in the transformer can be the voltage of phase A, phase B, or phase C of the transformer.

[0074] As an example, a transformer also includes a neutral line, which is usually connected to the ground at the location of the transformer. Therefore, under normal operating conditions, the voltage difference between any phase voltage in the transformer and the voltage of the neutral line is the same as the voltage difference between any phase voltage in the transformer and the grounding loop 1.

[0075] Step S80: If the voltage to ground is less than the preset voltage to ground threshold, the line monitoring results include a grounding loop 1 ungrounded fault.

[0076] Step S90: If the voltage to ground is greater than or equal to the preset voltage to ground threshold, the line monitoring results include no fault in the distribution box.

[0077] The preset ground voltage threshold can be set according to the actual situation; for example, the preset ground voltage threshold can be set to 75V.

[0078] As an example, under normal grounding conditions, since grounding loop 1 is connected to the earth, there will be a certain potential difference between the phase voltage and grounding loop 1. When the voltage to ground is less than the preset voltage to ground threshold, it indicates that the potential difference between the phase voltage and grounding loop 1 is small. This may mean that grounding loop 1 is not effectively connected to the earth, i.e., an ungrounded fault has occurred. Therefore, the line monitoring result determines that grounding loop 1 is ungrounded.

[0079] Secondly, such as Figure 4As shown, in one embodiment, this application provides a distribution box line monitoring device, which includes a grounding loop 1, an excitation output circuit 2, a sampling circuit 3, and a processing unit 4. The grounding loop 1 includes a first connecting line 11 and a second connecting line 12 for connecting a first grounding terminal outside the distribution box and a second grounding terminal inside the distribution box, forming a closed loop. The excitation output circuit 2 is connected to the grounding loop 1 and provides an excitation voltage to the grounding loop 1 to generate a loop current. The sampling circuit 3 is connected to the grounding loop 1 and samples the loop current to obtain a loop sampling signal. The processing unit 4 is connected to the sampling circuit 3 and obtains the distribution box line monitoring result based on the loop sampling signal.

[0080] In the above embodiment, an excitation voltage is provided to the grounding loop 1 through the excitation output circuit 2. Since the grounding loop 1 has a certain resistance, when the excitation voltage is applied to the grounding loop 1, a loop current will be generated flowing throughout the grounding loop 1. Then, the loop current is sampled by the sampling circuit 3 to obtain a loop sampling signal. The loop sampling signal can characterize the resistance of the grounding loop 1. Since the grounding loop 1 is a closed loop connecting the first grounding terminal and the second grounding terminal, even if the second grounding terminal is not directly grounded, the grounding reliability of the second grounding terminal in the distribution box can be indirectly reflected by the resistance of the grounding loop 1. Thus, the processing unit 4 can obtain the distribution box line monitoring results based on the loop sampling signal, and then monitor the grounding status of the second grounding terminal that is not directly grounded.

[0081] Reference Figure 5 As one embodiment of the excitation output circuit 2, the excitation output circuit 2 includes a voltage excitation sub-circuit 21 and a voltage transformer T1. The excitation sub-circuit is used to receive a square wave signal and output a first divided voltage and a second divided voltage according to the square wave signal. The voltage transformer T1 includes a primary coil connected to the excitation sub-circuit and used to receive the first and second divided voltages, and a secondary coil connected in series to the grounding loop 1 to generate an excitation voltage on the secondary coil.

[0082] The square wave signal can be output by processing unit 4 or by an independent pulse width modulation (PWM) generator. The duty cycle of the square wave signal can be 50%, and the frequency can be 1.5kHz, 2.5kHz, or 4kHz. Furthermore, to avoid problems such as overheating and aging of grounding loop 1 due to continuous excitation voltage output, the square wave signal can be output intermittently. Within a test cycle, the square wave signal is output only for a portion of the time; for example, if a test cycle is 5 seconds, the square wave signal can be output for 1 second, and output for the remaining 4 seconds.

[0083] The primary coil of voltage transformer T1 can have 50 turns, and the secondary coil can have 1 turn, so that the secondary coil is connected in series to the grounding loop 1.

[0084] In the above embodiment, the incoming square wave signal is amplified by the excitation sub-circuit, so that the voltage on the primary coil of the voltage transformer T1 is larger, thereby inducing an excitation voltage on the secondary coil of the voltage transformer T1, and directly transmitting the excitation voltage to the grounding loop 1.

[0085] As one embodiment of the voltage excitation sub-circuit 21, the voltage excitation sub-circuit 21 includes a first resistor R1, a switching transistor Q1, and a second resistor R2. The switching transistor Q1 includes a control electrode connected to a first terminal of the first resistor R1 for receiving a square wave signal, a first electrode connected to a second terminal of the first resistor R1 and a voltage source, and a second electrode connected to a first terminal of the second resistor R2 for outputting a first divided voltage. The second resistor R2 also includes a second terminal for outputting a second divided voltage and grounding.

[0086] As an example, when the square wave signal is not output, the switch Q1 is off, and the first and second voltage dividers are zero. When the square wave signal starts to output, the switch Q1 repeatedly turns on and off according to the frequency and duty cycle of the square wave signal, thereby obtaining the first and second voltage dividers across the second resistor R2. At the same time, the second resistor R2 can create a certain voltage difference between the first and second voltage dividers, thus giving the voltage transformer T1 a larger starting voltage initially.

[0087] Reference Figure 6 As one embodiment of sampling circuit 3, sampling circuit 3 includes a current transformer T2 and a sampling sub-circuit 31. The current transformer T2 includes a primary coil connected in series to the ground loop 1 for receiving the loop current, and a secondary coil connected to the sampling sub-circuit 31. Sampling sub-circuit 31 is used to obtain a loop sampling signal based on the signal on the secondary coil of the current transformer T2.

[0088] The primary coil of current transformer T2 can have 1 turn and is connected in series to grounding loop 1. The secondary coil of current transformer T2 can have 500 turns. When the excitation voltage is output to grounding loop 1, a PWM waveform loop current is generated in grounding loop 1 at the frequency corresponding to the excitation voltage. After the loop current flows through the primary coil of current transformer T2, a corresponding signal is generated on the secondary coil of current transformer T2. The sampling sub-circuit 31 samples the signal on the secondary coil of current transformer T2 to obtain the loop sampling signal.

[0089] As one embodiment of the sampling sub-circuit 31, the sampling sub-circuit 31 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a gating switch device U1. The gating switch device U1 includes a control terminal connected to a gating control signal, an input terminal connected to the third resistor R3, the current transformer T2, and the processing unit 4, a first output terminal connected to the fourth resistor R4, and a second output terminal connected to the fifth resistor R5. The third resistor R3 is also connected to a voltage source. The fourth resistor R4 and the fifth resistor R5 are also connected to the sixth resistor R6 and the processing unit 4. The seventh resistor R7 includes a first terminal connected to the sixth resistor R6, the current transformer T2, and the processing unit 4, and a second terminal grounded.

[0090] The gating switch U1 is used to control its input terminal to be connected to either the first output terminal or the second output terminal according to the gating control signal. When the input terminal of the gating switch U1 is connected to the first output terminal, the fourth resistor R4 and the sixth resistor R6 form a sampling resistor network to convert the current signal generated on the secondary coil of the current sensor into a voltage signal, thereby obtaining a loop sampling signal. Similarly, when the input terminal of the gating switch U1 is connected to the second output terminal, the fifth resistor R5 and the sixth resistor R6 form a sampling resistor network to convert the current signal generated on the secondary coil of the current sensor into a voltage signal, thereby obtaining a loop sampling signal. The fourth resistor R4 and the fifth resistor R5 are redundantly designed. For example, under normal operating conditions, the input terminal of the gating switch U1 can be controlled to be connected to the first output terminal, and the current signal generated on the secondary coil of the current sensor can be sampled through the fourth resistor R4 and the sixth resistor R6. After a certain period of operation, the input terminal of the gating switch U1 can be controlled to conduct with the second output terminal. The current signal generated on the secondary coil of the current sensor is sampled through the fifth resistor R5 and the sixth resistor R6. The sampling result is compared with the previous sampling result obtained through the fourth resistor R4 and the sixth resistor R6. If the difference between the two sampling results is small, the sampling result of the fourth resistor R4 and the sixth resistor R6 is determined to be accurate. Otherwise, the sampling result of the fourth resistor R4 and the sixth resistor R6 is determined to be abnormal, and the sampling abnormality information is output.

[0091] As an example, the third resistor R3 and the seventh resistor R7 are connected to the voltage source and ground respectively, so that the voltage across the third resistor R3 and the seventh resistor R7 is always positive. At this time, after connecting the two ends of the secondary coil of the current sensor to the third resistor R3 and the seventh resistor R7 respectively, the signal on the secondary coil of the current sensor is raised, so that the final loop sampling signal is a positive signal, so that the subsequent processing module can effectively identify and acquire the loop sampling signal.

[0092] As an example, combined Figure 6 I0_0 and I0_1 are the signals across the secondary coil of current transformer T2. Furthermore, the signal on the secondary coil of current transformer T2 can be scaled by the voltage divider of the seventh resistor R7 to obtain the scaled loop sampling signal II0_2, thus preventing the amplitude of the loop sampling signal from being too high and exceeding the range of the metering chip.

[0093] Reference Figure 7As one embodiment of processing unit 4, processing unit 4 includes a low-pass filter 41, a high-pass filter 42, a metering chip 43, and a processor 44. The low-pass filter 41 is connected to the sampling circuit 3 and is used to perform low-pass filtering on the loop sampling signal. The high-pass filter 42 is connected to the sampling circuit 3 and is used to perform high-pass filtering on the loop sampling signal. The metering chip 43 is connected to the low-pass filter 41 and the high-pass filter 42, and is used to sample the loop sampling signal after high-pass filtering and the loop sampling signal after low-pass filtering, respectively, to obtain a power frequency filtered signal and an excitation filtered signal. The processor 44 is connected to the metering chip 43 and is used to obtain the line monitoring result based on the power frequency filtered signal and the excitation filtered signal.

[0094] As an example, the processor 44 can also directly receive the loop sampling signal, perform harmonic analysis on the loop sampling signal to obtain the power frequency harmonic signal and the excitation harmonic signal, and select one of the power frequency harmonic signal and the power frequency filtered signal as the power frequency sampling signal, and select one of the excitation filtered signal and the excitation harmonic signal as the excitation sampling signal, thereby obtaining the line monitoring result based on the power frequency sampling signal and the excitation sampling signal. For the specific implementation method, please refer to the content of the method embodiment, which will not be repeated here.

[0095] As an example, the method of obtaining the power frequency filtered signal and the excitation filtered signal by the metering chip 43 after filtering by low-pass filter 41 and high-pass filter 42, allows for the direct acquisition of the power frequency filtered signal and the excitation filtered signal after filtering the loop sampling signal within a specific frequency range using low-pass filter 41 and high-pass filter 42. Furthermore, the sampling rate of the metering chip 43 is higher than that of the processor 44, requiring no further signal processing and making it easy to implement. However, low-pass filter 41 and high-pass filter 42 cannot accurately separate various irregular frequency components or harmonics that may exist in the loop signal. If harmonic interference in other frequencies is severe, the final power frequency filtered signal and excitation filtered signal may be inaccurate. On the other hand, the method of directly performing harmonic analysis on the loop sampling signal by the processor 44 to obtain the excitation harmonic signal and the power frequency harmonic signal, while decomposing the loop sampling signal into harmonic components of different frequencies and obtaining the distribution of the loop sampling signal at various frequencies, requires relatively complex mathematical calculations, placing higher demands on the processing power of the processor 44. On the other hand, the acquisition speed of the loop sampling signal by the processor 44 is lower than that of the metering chip 43, which may lead to sampling distortion of the loop sampling signal. Therefore, through mutual verification of the power frequency harmonic signal, the power frequency filtered signal, the excitation filtered signal, and the excitation harmonic signal, a more accurate power frequency sampling signal and excitation sampling signal are finally obtained.

[0096] In some embodiments, the high-pass filter 42 includes an eighth resistor R8 and a first capacitor C1. The first capacitor C1 includes a first terminal connected to the sampling circuit 3 and a second terminal connected to the metering chip 43 and the eighth resistor R8. The eighth resistor R8 includes a first terminal connected to the first capacitor C1 and a second terminal connected to the sampling circuit 3.

[0097] As an example, the high-pass filter 42 can be configured to have multiple orders depending on the actual situation. For example, if the high-pass filter 42 can be a fifth-order filter, then five sets of eighth resistors R8 and first capacitors C1 are set and the sets are connected in series.

[0098] In some embodiments, the low-pass filter 41 includes a second capacitor C2 and a ninth resistor R9. The ninth resistor R9 includes a first terminal connected to the sampling circuit 3 and a second terminal connected to the second capacitor C2 and the metering chip 43. The second capacitor C2 includes a first terminal connected to the ninth resistor R9 and a second terminal connected to the sampling circuit 3.

[0099] As an example, the low-pass filter 41 can be configured to have multiple orders depending on the actual situation. For example, the low-pass filter 41 can be a second-order filter, in which case two sets of second capacitors C2 and ninth resistors R9 are set and connected in series with each set.

[0100] Reference Figure 8 As a further embodiment of the distribution box line monitoring device, the distribution box line monitoring device also includes a box detection circuit 5, which is used to sample the voltage between the outer shell of the distribution box and the grounding loop 1 to obtain the box voltage value.

[0101] As an example, the enclosure detection circuit 5 includes a measuring transformer T3 and a tenth resistor R10. The measuring transformer T3 includes a primary side first terminal connected to the enclosure of the distribution box, a primary side second terminal connected to the grounding loop 1, a secondary side first terminal connected to the tenth resistor R10 and the processing unit 4, and a secondary side second terminal connected to the second terminal of the tenth resistor R10 and ground. The secondary side of the measuring transformer T3 is used to output the enclosure voltage value. The processing unit 4 is also used to obtain the line monitoring result based on the enclosure voltage value.

[0102] In this method, the turns ratio of the primary and secondary sides of the current transformer T3 can be 1:1. The tenth resistor R10 is the sampling resistor for the secondary side of the current transformer T3. After the secondary side of the current transformer T3 outputs the enclosure voltage value, it is transmitted to the processing unit 4 through the tenth resistor R10. As an example, the specific implementation method for obtaining the line monitoring result based on the enclosure voltage value can be found in the method embodiment, which will not be repeated here.

[0103] Reference Figure 9As a further embodiment of the distribution box line monitoring device, the distribution box line monitoring device also includes a ground detection circuit 6, which is used to sample the voltage between any phase voltage of the transformer in the distribution box and the voltage of the grounding loop 1 to obtain the ground voltage value.

[0104] As an example, the ground detection circuit 6 includes a diode D1, an optocoupler U2, and an eleventh resistor R11. Diode D1 includes an anode for receiving any phase voltage and a cathode connected to the optocoupler U2. Optocoupler U2 includes an anode connected to diode D1, a cathode connected to ground loop 1, a collector connected to a voltage source, and an emitter connected to the eleventh resistor R11 and processing unit 4 for outputting the ground voltage value. The eleventh resistor R11 includes a first terminal connected to the optocoupler U2 and a second terminal grounded. Processing unit 4 is also used to obtain line monitoring results based on the ground voltage value.

[0105] In the above embodiment, the phase voltage is first rectified by diode D1 using half-wave rectification. The phase voltage after half-wave rectification is conducted to the ground loop 1 through the light-emitting diode in optocoupler U2. Since optocoupler U2 operates in the linear region, the greater the voltage difference between the phase voltage and the ground loop 1, the greater the conduction degree of the emitter and collector of optocoupler U2. The voltage difference between the phase voltage and the ground loop 1 can be characterized by the emitter signal of optocoupler U2. Then, the emitter signal of optocoupler U2 is sampled by the eleventh resistor R11 to output the ground voltage value to the processing unit 4, thus realizing the sampling of the ground voltage value.

[0106] Thirdly, in one embodiment, this application provides an electronic device, such as... Figure 10 As shown, it illustrates the structure of the electronic device involved in this application, specifically: The electronic device may include components such as a control processor 401 with one or more processing cores, a memory 402 with one or more computer-readable storage media, a power supply 403, and an input unit 404. Those skilled in the art will understand that... Figure 5 The structure of the electronic device shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, or combine certain components, or have different component arrangements. Wherein: The control processor 401 is the control center of the electronic device. It connects various parts of the electronic device via various interfaces and lines, and performs various functions and processes data by running or executing software programs and / or modules stored in the memory 402, and by calling data stored in the memory 402, thereby providing overall monitoring of the electronic device. Optionally, the control processor 401 may include one or more processing cores; preferably, the control processor 401 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and computer programs, and the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into the control processor 401.

[0107] The memory 402 can be used to store software programs and modules. The control processor 401 executes various functional applications and data processing by running the software programs and modules stored in the memory 402. The memory 402 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, computer programs required for at least one function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the server, etc. In addition, the memory 402 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, the memory 402 may also include a memory controller to provide control processor 401 with access to the memory 402.

[0108] The electronic device also includes a power supply 403 that supplies power to various components. Preferably, the power supply 403 can be logically connected to the control processor 401 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The power supply 403 may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

[0109] The electronic device may also include an input unit 404, which can be used to receive input digital or character information, and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control.

[0110] Although not shown, the electronic device may also include a display unit, etc., which will not be described in detail here. Specifically, in this embodiment, when the electronic device is a model training electronic device, the control processor 401 in the electronic device will load the executable files corresponding to the processes of one or more computer programs into the memory 402 according to the following instructions, and the control processor 401 will run the computer programs stored in the memory 402 to perform the steps of the above method.

[0111] Those skilled in the art will understand that all or part of the steps in any of the methods in the above embodiments can be performed by a computer program or by a computer program controlling related hardware. The computer program can be stored in a computer-readable storage medium and loaded and executed by the control processor 401.

[0112] Fourthly, in one embodiment, this application provides a storage medium storing a plurality of computer programs that can be loaded by a processor to perform the steps of the above-described method.

[0113] It will be understood by those skilled in the art that any references to memory, storage, database, or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), Synchlink, DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0114] Since the computer program stored in the storage medium can execute the steps in the distribution box line monitoring device in any embodiment of the present application, the beneficial effects that the distribution box line monitoring device in any embodiment of the present application can achieve can be realized. For details, please refer to the previous embodiments, which will not be repeated here.

[0115] For details on the implementation of each of the above operations, please refer to the previous examples, which will not be repeated here.

[0116] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the detailed descriptions of other embodiments above, which will not be repeated here.

[0117] The above provides a detailed description of a power distribution box line monitoring device provided in this application. Specific examples have been used to illustrate the principle and implementation of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this application. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this application. Therefore, the content of this specification should not be construed as a limitation of this application.

[0118] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A power distribution box line monitoring device, characterized in that, include: A grounding loop includes a first connecting line and a second connecting line for connecting a first grounding terminal outside the distribution box and a second grounding terminal inside the distribution box, wherein the first connecting line and the second connecting line form a closed loop; An excitation output circuit, connected to the grounding loop, is used to provide an excitation voltage to the grounding loop so as to generate a loop current in the grounding loop; A sampling circuit, connected to the grounding loop, is used to sample the loop current to obtain a loop sampling signal; The processing unit, connected to the sampling circuit, is used to obtain the line monitoring results of the distribution box based on the loop sampling signal.

2. The distribution box line monitoring device according to claim 1, characterized in that, The excitation output circuit includes a voltage excitation sub-circuit and a voltage transformer; The excitation sub-circuit is used to receive a square wave signal and output a first voltage divider and a second voltage divider according to the square wave signal; The voltage transformer includes a primary coil connected to the excitation sub-circuit and used to receive the first voltage divider voltage and the second voltage divider voltage, and a secondary coil connected in series to the grounding loop to generate the excitation voltage on the secondary coil.

3. The distribution box line monitoring device according to claim 2, characterized in that, The voltage excitation sub-circuit includes a first resistor, a switching transistor, and a second resistor. The switching transistor includes a control electrode connected to a first terminal of the first resistor and used to receive the square wave signal, a first electrode connected to a second terminal of the first resistor and a voltage source, and a second electrode connected to a first terminal of the second resistor and used to output the first voltage divider voltage. The second resistor also includes a second terminal for outputting the second voltage divider and grounding.

4. The distribution box line monitoring device according to claim 1, characterized in that, The sampling circuit includes a current transformer and a sampling sub-circuit; The current transformer includes a primary coil connected in series with the grounding loop and used to receive the loop current, and a secondary coil connected to the sampling sub-circuit. The sampling sub-circuit is used to obtain the loop sampling signal based on the signal on the secondary coil of the current transformer.

5. The distribution box line monitoring device according to claim 4, characterized in that, The sampling sub-circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, and a gating switch. The gating switch device includes a control terminal that receives the gating control signal, an input terminal connected to the third resistor, the current transformer and the processing unit, a first output terminal connected to the fourth resistor and a second output terminal connected to the fifth resistor; The third resistor is also connected to a voltage source; the fourth and fifth resistors are also connected to the sixth resistor and the processing unit; The seventh resistor includes a first terminal connected to the sixth resistor, the current transformer, and the processing unit, and a second terminal grounded.

6. The distribution box line monitoring device according to claim 1, characterized in that, The processing unit includes a low-pass filter, a high-pass filter, a metering chip, and a processor; The low-pass filter is connected to the sampling circuit and is used to perform low-pass filtering on the loop sampling signal. The high-pass filter is connected to the sampling circuit and is used to perform high-pass filtering on the loop sampling signal; The metering chip is connected to the low-pass filter and the high-pass filter, and is used to sample the loop sampling signal after the high-pass filtering and the loop sampling signal after the low-pass filtering, respectively, to obtain the power frequency filtered signal and the excitation filtered signal. The processor, connected to the metering chip, is used to obtain the line monitoring results based on the power frequency filter signal and the excitation filter signal.

7. The distribution box line monitoring device according to claim 6, characterized in that, The high-pass filter includes an eighth resistor and a first capacitor; The first capacitor includes a first terminal connected to the sampling circuit and a second terminal connected to the metering chip and the eighth resistor; The eighth resistor includes a first end connected to the first capacitor and a second end connected to the sampling circuit.

8. The distribution box line monitoring device according to claim 6, characterized in that, The low-pass filter includes a second capacitor and a ninth resistor; The ninth resistor includes a first terminal connected to the sampling circuit and a second terminal connected to the second capacitor and the metering chip; The second capacitor includes a first terminal connected to the ninth resistor and a second terminal connected to the sampling circuit.

9. The distribution box line monitoring device according to claim 1, characterized in that, It also includes a housing detection circuit, used to sample the voltage between the housing of the distribution box and the grounding loop to obtain the housing voltage value; The enclosure detection circuit includes a measuring current transformer and a tenth resistor; The measuring transformer includes a primary side first terminal connected to the outer casing of the distribution box, a primary side second terminal connected to the grounding loop, a secondary side first terminal connected to the tenth resistor and the processing unit, and a secondary side second terminal connected to the second terminal of the tenth resistor and ground. The secondary side of the measuring transformer is used to output the box voltage value. The processing unit is also used to obtain the line monitoring results based on the voltage value of the enclosure.

10. The distribution box line monitoring device according to claim 1, characterized in that, It also includes a ground detection circuit, used to sample the voltage between any phase voltage in the transformer in the distribution box and the voltage between the grounding loop to obtain the ground voltage value; The ground detection circuit includes a diode, an optocoupler, and an eleventh resistor. The diode includes an anode for receiving any one of the phase voltages and a cathode connected to the optocoupler; The optocoupler includes an anode connected to the diode, a cathode connected to the grounding loop, a collector connected to the voltage source, and an emitter connected to the eleventh resistor and the processing unit and used to output the voltage value to ground; the eleventh resistor includes a first end connected to the optocoupler and a second end grounded. The processing unit is also used to obtain the line monitoring results based on the voltage value to ground.

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