Grounding detection method and device based on signal injection technology

Abstract

The invention discloses a grounding detection method and device based on a signal injection technology, and belongs to the technical field of grounding fault detection, and the method comprises the steps: S1, setting a detection signal parameter based on the historical operation data of a to-be-detected circuit, and generating a detection signal through the grounding detection device based on the signal injection technology; s2, adjusting the detection signal based on the detection signal parameter to obtain an optimal detection signal, and inputting the optimal detection signal into the circuit to be detected; s3, after the optimal detection signal is input into the to-be-detected circuit, detection data are collected based on the loop structure of the to-be-detected circuit; s4, performing ground fault analysis based on the detection data, and determining a ground loop in the to-be-detected circuit according to a corresponding relation between the detection data and the loop structure of the to-be-detected circuit and a ground fault analysis result; according to the invention, the problem of low detection result accuracy caused by the fact that the influence of the injection signal frequency on the detection device is not considered in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ground fault detection, and in particular to a ground fault detection method and device based on signal injection technology. Background Art

[0002] The DC system corresponding to the secondary equipment in the substation or power plant may occasionally experience grounding events, and the configured DC power grounding finder can only detect the grounded circuit breaker circuit, and cannot accurately detect the signal circuits under the equipment to which the circuit breaker circuit belongs. In view of this, some scholars have proposed a grounding finder based on signal injection technology to solve the problem of detection accuracy. However, the signal generator of this new finder must use an AC signal to generate a signal that is different from the DC phase. Combined with the DC system, multi-point grounding is strictly prohibited, resulting in a capacitor being connected in series between the signal generator and the DC system to be detected to maintain insulation. If the capacity of the capacitor is too large, it is easy to cause malfunction of the DC system, and if the capacity of the capacitor is too small, the insulation performance is poor. At the same time, due to the influence of the secondary cable distribution of the DC system on the capacitor, the frequency of the injected signal is too high, which makes it easy for the finder to detect false signals, resulting in erroneous detection results. If the frequency of the injected signal is too low, the capacity of the capacitor needs to be increased to maintain the detection effect.

[0003] Chinese patent, publication number: CN118795382A, publication date: October 18, 2024, discloses a substation grounding fault positioning device and method, including: a host end and a handheld end, the host end and the handheld end are communicated with each other, and the host end includes at least the following modules: a characteristic signal module is used to generate a preset test signal and input it into the circuit to be detected; a fault test module is used to detect the response signal in the circuit to be detected; a first main control module is used to execute a preset fault detection algorithm to analyze the response signal and the current signal, determine whether there is an insulation fault in the circuit, and coordinate the work of each module according to the input control instruction; the handheld end includes at least the following modules: a current sampling module is used to measure the current signal after the circuit to be detected inputs the test signal; the second main control module is used to receive the control signal output by the first main control module, and execute the preset logic operation program and control action according to the control signal; however, the invention does not consider the influence of the injection signal frequency on the detection device, resulting in low accuracy of the detection result. Summary of the invention

[0004] The purpose of the present invention is to address the problem that the prior art does not consider the influence of the injection signal frequency on the detection device, resulting in low accuracy of the detection result; a grounding detection method and device based on signal injection technology are proposed, the detection signal is adjusted through the historical operation data of the circuit to be tested to obtain an optimal detection signal, the optimal detection signal is input into the circuit to be tested for detection, and the collected detection data is subjected to fault analysis to determine the grounding loop in the circuit to be tested, which can not only accurately analyze the location of the grounding event in the circuit to be tested, that is, the grounding loop, but also can set the capacitance of the corresponding detection device based on the control of the detection signal frequency, thereby avoiding misjudgment of the grounding fault point caused by the capacitance of the detection device.

[0005] In a first aspect, a technical solution provided in an embodiment of the present invention is a ground detection method based on a signal injection technology, comprising the following steps: S1. Setting detection signal parameters based on historical operation data of the circuit to be tested, and generating a detection signal by a ground detection device based on a signal injection technology; S2, adjusting the detection signal based on the detection signal parameter to obtain an optimal detection signal, and inputting the optimal detection signal into the circuit to be tested; S3, after the optimal detection signal is input into the circuit to be tested, collecting detection data based on the loop structure of the circuit to be tested; S4. Performing a ground fault analysis based on the detection data, and determining a ground loop in the circuit to be tested according to a correspondence between the detection data and a loop structure of the circuit to be tested and a result of the ground fault analysis.

[0006] In the present solution, setting the detection signal parameters based on the historical operating data of the circuit to be tested can make the detection signal adjusted according to the detection signal parameters more consistent with the actual operating conditions of the circuit to be tested, which helps to improve the accuracy of ground fault detection, effectively avoid false alarms and missed reports of grounding events, and can also increase the scope of application of the corresponding detection device, thereby improving the practicality of the detection device. In addition, adjusting the detection signal based on the detection signal parameters to obtain the best detection signal can ensure that the loss of the detection signal during the transmission process is minimized, thereby improving the utilization rate of the detection signal. By collecting detection data based on the loop structure of the circuit to be tested, comprehensive and accurate detection data can be collected, thereby ensuring the integrity and accuracy of the data. In addition, the correlation between the detection data and the loop structure of the circuit to be tested can be obtained while collecting the data, thereby helping to analyze the specific location where the ground fault occurs. Finally, fault analysis is performed on the collected detection data to determine the grounding loop in the circuit to be tested, thereby accurately analyzing the specific location where the grounding event occurs in the circuit to be tested, thereby significantly improving the accuracy of the detection results.

[0007] Preferably, in S1, the specific process of setting the detection signal parameters based on the historical operation data of the circuit to be tested is: S111, acquiring historical operation data of the circuit to be tested, and cleaning the historical operation data to obtain a complete data set; S112, extracting a frequency variation range, a current variation range, and a voltage variation range based on the complete data set; S113, setting a detection signal frequency range based on the frequency variation range, setting a detection signal current range based on the current variation range, and setting a detection signal voltage range based on the voltage variation range; S114, sorting out the detection signal frequency range, the detection signal current range and the detection signal voltage range to obtain detection signal parameters.

[0008] In this solution, cleaning the historical operation data can eliminate unnecessary or repeated data such as abnormal values ​​and repeated values ​​in the historical operation data. The frequency change range, current change range and voltage change range are extracted based on the cleaned historical operation data, which can reflect the operating characteristics of the circuit to be tested, and thus make the corresponding set detection signal parameters fit the actual working conditions of the circuit to be tested.

[0009] Preferably, in S2, the specific process of adjusting the detection signal based on the detection signal parameter to obtain the optimal detection signal is: adjusting the voltage of the detection signal based on the detection signal voltage range in the detection signal parameter, and determining that the detection signal corresponding to the voltage is a voltage-stabilized signal when the voltage is within the detection signal voltage range; Adjusting the current of the voltage stabilization signal based on the detection signal current range in the detection signal parameter, and determining that the voltage stabilization signal corresponding to the current is a current limiting signal when the current is within the detection signal current range; The frequency of the current limiting signal is adjusted based on the detection signal frequency range in the detection signal parameter, and when the frequency is within the detection signal frequency range, the frequency corresponding current limiting signal is determined to be the optimal detection signal.

[0010] Preferably, in S3, the specific process of collecting the detection data based on the loop structure of the circuit to be tested is: S311, setting detection points based on the loop structure of the circuit to be tested, and sequentially marking the detection points to obtain a detection point set; S312, sequentially detecting the detection points in the detection point set based on the marking order of the detection points to obtain detection data corresponding to the detection points, and arranging the detection data corresponding to the detection points to obtain detection data.

[0011] This scheme collects detection data through detection points set in the circuit to be tested, and can obtain the corresponding relationship between the detection points and the detection data, and then obtain the correlation between the detection data and the loop structure of the circuit to be tested. During the detection, the detection points in the detection point concentration are detected in sequence according to the marking order. The source of the detection data can be quickly tracked according to the marking order, and the traceability and positioning of the detection data can be realized. Secondly, according to the corresponding relationship between the detection points and the detection data, multiple detection data of the same detection point can be longitudinally compared to improve the stability of the detection data.

[0012] Preferably, in S4, the specific process of performing ground fault analysis based on the detection data is: The detection data is compared with a preset fault threshold. If the detection data is greater than the preset fault threshold, it is determined that a grounding event has occurred in the circuit to be tested corresponding to the detection data, and the detection data greater than the preset fault threshold is marked as grounding fault data. If the detection data is less than or equal to the preset fault threshold, it is determined that a grounding event has not occurred in the circuit to be tested corresponding to the detection data.

[0013] Preferably, in S4, the specific process of determining the ground loop in the circuit to be tested according to the corresponding relationship between the detection data and the circuit loop structure to be tested and the result of the ground fault analysis is: S411, when the ground fault analysis result clearly indicates that a ground fault occurs in the circuit to be tested corresponding to the corresponding detection data, determining a fault detection point according to the ground fault data in the detection data and a detection point corresponding to the detection data; S412, determining the grounding loop according to the corresponding relationship between the detection point and the loop in the circuit to be tested and the fault detection point.

[0014] On the other hand, a technical solution also provided in an embodiment of the present invention is a ground detection device based on a signal injection technology, comprising: a signal generator, a signal current clamp meter, and a coordination filter component; The signal generator is used to generate a detection signal, one end of the signal generator is grounded, and the other end is electrically connected to the input end of the coordination filter component; The coordination filter component is used to adjust the frequency of the detection signal, and the output end of the coordination filter component is electrically connected to the detection end of the circuit to be tested; the signal current clamp meter is used to detect whether there is a detection signal in the circuit to be tested, and the input end of the signal current clamp meter is electrically connected to the tested end of the circuit to be tested.

[0015] In this solution, the coordination filter component can adjust the detection signal generated by the signal generator so that the frequency of the detection signal meets the detection requirements while not affecting the normal operation of the circuit being detected, that is, the circuit to be tested.

[0016] Furthermore, the coordinated filtering component includes: a reactor, a resistor, and a capacitor; The input end of the reactor is electrically connected to the output end of the capacitor, the input end of the reactor is electrically connected to one end of the resistor, the other end of the resistor is electrically connected to the input end of the capacitor, the input end of the capacitor is electrically connected to the signal generator as the input end of the coordinated filtering component, and the output end of the reactor is electrically connected to the detection end of the circuit to be tested as the output end of the coordinated filtering component.

[0017] Furthermore, the reactor is specifically a saturated reactor with a saturated structure.

[0018] In this solution, the saturated reactor with a saturated structure has a certain degree of nonlinearity, which can better damp the transient charging current at the moment of access to the circuit, thereby protecting the circuit to be tested and the electrical components in the coordinated filter assembly.

[0019] Furthermore, the signal generator includes: a protection module, a signal driving module, a power amplifier module, a voltage regulating module, and a field effect current limiting module; One end of the protection module is grounded, the other end of the protection module is electrically connected to the protection end of the voltage regulating module, the input end of the voltage regulating module is electrically connected to the output end of the power amplifier module, the input end of the power amplifier module is electrically connected to the output end of the signal driving module, the output end of the voltage regulating module is electrically connected to the input end of the field effect current limiting module, and the output end of the field effect current limiting module is electrically connected to the input end of the coordination filtering component.

[0020] The present invention has at least the following substantial effects: The present application sets the detection signal parameters based on the historical operation data of the circuit to be tested, so that the detection signal adjusted according to the detection signal parameters can be more consistent with the actual operation status of the circuit to be tested, which is helpful to improve the accuracy of ground fault detection, effectively avoid false alarms and missed ground events, and can also increase the application scope of the corresponding detection device and improve the practicality of the detection device. In addition, adjusting the detection signal based on the detection signal parameters to obtain the best detection signal can ensure that the loss of the detection signal during the transmission process is minimized, thereby improving the utilization rate of the detection signal. By collecting detection data based on the loop structure of the circuit to be tested, comprehensive and accurate detection data can be collected, thereby ensuring the integrity and accuracy of the data, and the detection signal can be collected in the circuit to be tested. By setting detection points in the road, the correspondence between the detection points and the detection data can be obtained, and then the correlation between the detection data and the loop structure of the circuit to be tested can be obtained. By detecting the detection points in sequence according to the marking order, the source of the detection data can be quickly traced according to the marking order, and the traceability and positioning of the detection data can be achieved, which is helpful for analyzing the specific location of the grounding fault. Secondly, according to the correspondence between the detection points and the detection data, multiple detection data of the same detection point can be compared vertically to improve the stability of the detection data. Finally, fault analysis is performed on the collected detection data to determine the grounding loop in the circuit to be tested. The specific location of the grounding event in the circuit to be tested can be accurately analyzed, which significantly improves the accuracy of the detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings. The drawings are only for the purpose of illustrating preferred embodiments and are not to be considered as limiting the present invention. Also, the same reference symbols are used throughout the drawings to represent the same parts.

[0022] Figure 1 It is a flow chart of the ground detection method based on the signal injection technology of the present invention; Figure 2 It is a structural schematic diagram of a ground detection device based on a signal injection technology of the present invention; Figure 3 A schematic diagram of the structure of the coordinated filtering component; Figure 4 This is a structural diagram of the signal generator. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation method described herein is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the operations (or steps) as sequential processes, many of the operations (or steps) therein can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the drawings; the process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0025] Embodiment 1: like Figure 1 As shown, this embodiment provides a ground detection method based on signal injection technology, including the following steps: S1. Setting detection signal parameters based on historical operation data of the circuit to be tested, and generating a detection signal based on a grounding detection device using a signal injection technology.

[0026] In one embodiment, the specific process of setting the detection signal parameters based on the historical operation data of the circuit to be tested is: S111, acquiring historical operation data of the circuit to be tested, and cleaning the historical operation data to obtain a complete data set; S112, extracting a frequency variation range, a current variation range, and a voltage variation range based on the complete data set; S113, setting a detection signal frequency range based on the frequency variation range, setting a detection signal current range based on the current variation range, and setting a detection signal voltage range based on the voltage variation range; S114, sorting out the detection signal frequency range, the detection signal current range and the detection signal voltage range to obtain detection signal parameters.

[0027] In this embodiment, a frequency curve graph, a current curve graph and a voltage curve graph of the historical operation data can be plotted to extract the corresponding frequency change range, current change range and voltage change range. A theoretical curve graph of the detection signal parameters can also be plotted, and the theoretical curve graph, frequency curve graph, current curve graph and voltage curve graph can be fitted to observe whether the detection signal parameters are reasonable. Specifically, the voltage peak value in the detection signal parameters does not exceed 30V, and the current peak value does not exceed 3mA, and the frequency is automatically adjusted according to the corresponding electrical components in the grounding detection device based on signal injection technology.

[0028] S2. Adjust the detection signal based on the detection signal parameter to obtain an optimal detection signal, and input the optimal detection signal into the circuit to be tested.

[0029] In one embodiment, the specific process of adjusting the detection signal based on the detection signal parameter to obtain the best detection signal is: adjusting the voltage of the detection signal based on the detection signal voltage range in the detection signal parameter, and determining that the detection signal corresponding to the voltage is a voltage-stabilized signal when the voltage is within the detection signal voltage range; Adjusting the current of the voltage stabilization signal based on the detection signal current range in the detection signal parameter, and determining that the voltage stabilization signal corresponding to the current is a current limiting signal when the current is within the detection signal current range; The frequency of the current limiting signal is adjusted based on the detection signal frequency range in the detection signal parameter, and when the frequency is within the detection signal frequency range, the frequency corresponding current limiting signal is determined to be the optimal detection signal.

[0030] In this embodiment, the voltage, current and frequency of the detection signal need to be adjusted according to the set detection signal parameters. The specific adjustment process needs to be carried out based on the corresponding grounding detection device based on signal injection technology. If the detection signal adjustment electrical components in the grounding detection device based on signal injection technology have a sequence, then the adjustment of the voltage, current and frequency of the detection signal also has a corresponding adjustment sequence. In this embodiment, the sequence of first adjusting the detection signal voltage, then limiting the detection signal current, and finally adjusting the detection signal frequency can be adopted.

[0031] S3. After the optimal detection signal is input into the circuit to be tested, detection data is collected based on the loop structure of the circuit to be tested.

[0032] In one embodiment, the specific process of collecting detection data based on the loop structure of the circuit to be tested is: S311, setting detection points based on the loop structure of the circuit to be tested, and sequentially marking the detection points to obtain a detection point set; S312, sequentially detecting the detection points in the detection point set based on the marking order of the detection points to obtain detection data corresponding to the detection points, and arranging the detection data corresponding to the detection points to obtain detection data.

[0033] In this embodiment, since it is necessary to measure the DC branches, i.e., loops, where grounding events may occur, one by one, and sometimes the same loop is measured multiple times in order to further improve the accuracy of the data, monitoring points are set corresponding to different loops of the circuit to be tested, which facilitates the organization of detection data, and the detection data is matched with the loop of the circuit to be tested. At the same time, the correlation between the detection data and the loop structure of the circuit to be tested can also be obtained.

[0034] S4. Performing a ground fault analysis based on the detection data, and determining a ground loop in the circuit to be tested according to a correspondence between the detection data and a loop structure of the circuit to be tested and a result of the ground fault analysis.

[0035] In one embodiment, the specific process of performing ground fault analysis based on the detection data is as follows: The detection data is compared with a preset fault threshold. If the detection data is greater than the preset fault threshold, it is determined that a grounding event has occurred in the circuit to be tested corresponding to the detection data, and the detection data greater than the preset fault threshold is marked as grounding fault data. If the detection data is less than or equal to the preset fault threshold, it is determined that a grounding event has not occurred in the circuit to be tested corresponding to the detection data.

[0036] In this embodiment, if a grounding event occurs in the loop corresponding to the circuit to be tested, a detection signal can be measured in the corresponding loop; if a grounding event does not occur in the loop corresponding to the circuit to be tested, a detection signal cannot be measured in the corresponding loop; therefore, the fault threshold can be set to 0. When the detection data is greater than 0, it proves that a loop regarding the detection signal is formed in the loop of the circuit to be tested, and thus the detection signal can be measured; when the detection data is less than or equal to 0, it proves that no loop regarding the detection signal is formed in the loop of the circuit to be tested, and thus the detection signal cannot be measured.

[0037] In one embodiment, the specific process of determining the ground loop in the circuit to be tested according to the correspondence between the detection data and the circuit loop structure to be tested and the result of the ground fault analysis is: S411, when the ground fault analysis result clearly indicates that a ground fault occurs in the circuit to be tested corresponding to the corresponding detection data, determining a fault detection point according to the ground fault data in the detection data and a detection point corresponding to the detection data; S412, determining the grounding loop according to the corresponding relationship between the detection point and the loop in the circuit to be tested and the fault detection point.

[0038] On the other hand, Figure 2 As shown, a technical solution also provided in the embodiment of the present invention is a ground detection device based on signal injection technology, comprising: a signal generator, a signal current clamp meter, and a coordination filter component; The signal generator is used to generate a detection signal, one end of the signal generator is grounded, and the other end is electrically connected to the input end of the coordination filter component; The coordination filter component is used to adjust the frequency of the detection signal, and the output end of the coordination filter component is electrically connected to the detection end of the circuit to be tested; the signal current clamp meter is used to detect whether there is a detection signal in the circuit to be tested, and the input end of the signal current clamp meter is electrically connected to the tested end of the circuit to be tested.

[0039] In this embodiment, when the grounding detection device based on signal injection technology is in use, the signal generator will emit a low-voltage and low-frequency AC signal to prevent interference with the corresponding DC system, that is, the operation of the circuit to be tested. The coordination filter component will adjust the AC signal to make the AC signal more consistent with the actual working conditions of the DC system to prevent the AC signal from causing an impact on the DC system at the moment of access. After the AC signal is input into the DC system, it is necessary to use a signal current clamp meter to measure the DC branches one by one. When a grounding event occurs in the DC branch, a loop about the AC signal will be generated due to the connection of the signal current clamp meter, and the AC signal can be measured. Therefore, it is possible to judge whether a grounding event occurs in the corresponding DC branch based on whether the signal current clamp meter displays the AC signal.

[0040] like Figure 3 As shown, the coordinated filtering component includes: a reactor, a resistor, and a capacitor; The input end of the reactor is electrically connected to the output end of the capacitor, the input end of the reactor is electrically connected to one end of the resistor, the other end of the resistor is electrically connected to the input end of the capacitor, the input end of the capacitor is electrically connected to the signal generator as the input end of the coordinated filtering component, and the output end of the reactor is electrically connected to the detection end of the circuit to be tested as the output end of the coordinated filtering component.

[0041] Preferably, the reactor is a saturated reactor having a saturated structure.

[0042] In this embodiment, since the signal generator must use an AC signal and a DC system, that is, the circuit to be tested is strictly prohibited from being grounded at multiple points, the signal generator must be insulated between the ground terminal and the DC system. A capacitor can be connected in series between the signal generator and the DC system. At the same time, due to the influence of the cable distribution of the DC system on the capacitor, the frequency of the AC signal cannot be too high, otherwise the branch in the DC system where no grounding event occurs will also generate a false signal due to the influence of the cable distribution on the capacitor, causing the signal current clamp meter to clamp the false signal and cause misjudgment. If the frequency of the AC signal is too low, the capacity of the capacitor must be increased. If the capacitor carries residual charge at the moment of connection or poor contact causes the residual charge to impact the DC system, the relay in the DC system will malfunction, affecting the normal operation of the DC system. Therefore, a saturated inductor can be connected in series on the basis of the capacitor, and a resistor can be connected in parallel based on the capacitor to obtain a tuned filter circuit, which can not only adjust the frequency of the detection signal output by the signal generator, so that the detection signal power supply is greatly reduced after being affected by the capacitive reactance of the capacitor, but also reduce the capacity of the capacitor, so that the capacity of the capacitor is maintained within tens of microfarads or even ten microfarads.

[0043] like Figure 4 As shown, the signal generator includes: a protection module, a signal driving module, a power amplifier module, a voltage regulating module, and a field effect current limiting module; One end of the protection module is grounded, the other end of the protection module is electrically connected to the protection end of the voltage regulating module, the input end of the voltage regulating module is electrically connected to the output end of the power amplifier module, the input end of the power amplifier module is electrically connected to the output end of the signal driving module, the output end of the voltage regulating module is electrically connected to the input end of the field effect current limiting module, and the output end of the field effect current limiting module is electrically connected to the input end of the coordination filtering component.

[0044] In this embodiment, in order to control the current of the detection signal and prevent the current from increasing when the output end of the signal generator is short-circuited, a field effect tube constant current circuit, that is, a field effect current limiting module, can be connected in series between the transformer, that is, the voltage regulating module and the output end, so that the signal generator is converted from a traditional voltage signal source to a current signal source. In this way, even if a short circuit occurs at the output end, due to the presence of the field effect tube constant current circuit, the current of the detection signal will not change, and the transient impact current at the moment of access can also be eliminated, thereby limiting the current of the detection signal; the field effect tube constant current circuit can use two groups of high-power MOSFETs with a withstand voltage of up to 800V in series, so that even if one MOSFET is broken down, the other MOSFET can also play a perfect current limiting role, thereby minimizing the failure probability of the field effect tube constant current circuit.

[0045] In addition, the ground detection device based on the signal injection technology described in this embodiment should meet the qualification requirements, and the qualification requirements specifically include: 1) Requirements for insulation resistance of signal generator; Use a 500V megohmmeter to test the insulation resistance between the DC bus terminal and the ground terminal of the signal generator. Regardless of polarity, power-on or power-off status, after continuous testing for 1 minute, the insulation resistance should be no less than 1 megohm; 2) About the output characteristics of the signal generator; a. When the signal generator is powered on, the output voltage peak value of the signal generator shall not exceed 30V, and the output current peak value of the signal generator shall not exceed 3mA, and this requirement shall still be met at the moment of power on and off; b corresponds to the power-on state of the signal generator. When the signal generator is connected to the electromagnetic relay coil with an operating power greater than 1w and a coil voltage between 12-220V in the DC system, and the electromagnetic relay does not malfunction after one hour; 3) Requirements for the ground detection device based on signal injection technology after it is connected to the DC system; a corresponds to the power-on state of the signal generator, the ground terminal of the signal generator is connected to the positive bus of the normal DC system, and the bus terminal of the signal generator is connected to the negative bus of the normal DC system. After one hour, the voltage deviation of the DC bus to the ground does not exceed 10V and the insulation detector has no alarm; b corresponds to the power-on state of the signal generator, the ground terminal of the signal generator is in intermittent contact with the positive bus of the normal DC system, the bus terminal of the signal generator is in intermittent contact with the negative bus of the normal DC system, the contact frequency is not less than 1 time / second, the voltage deviation of the DC bus to the ground does not exceed 10V and the insulation detector has no alarm; c. The ground terminal of the signal generator is connected to the positive bus of the normal DC system, and the bus terminal of the signal generator is connected to the negative bus of the normal DC system. The signal generator maintains a switching state at a frequency of not less than 1 time / second, the DC bus voltage deviation to ground does not exceed 10V, and the insulation detector has no alarm; d. Simulate metallic grounding on the positive side of the relay of the hard-contact signal loop of the shut-down secondary equipment. When the signal generator is turned on, the grounding terminal of the signal generator is in intermittent contact with the positive bus of the normal DC system, and the bus terminal of the signal generator is in intermittent contact with the negative bus of the normal DC system. The relay does not malfunction for 5 minutes.

[0046] This embodiment has at least the following substantial effects: This embodiment sets the detection signal parameters based on the historical operation data of the circuit to be tested, so that the detection signal adjusted according to the detection signal parameters can be more consistent with the actual operation status of the circuit to be tested, which is helpful to improve the accuracy of ground fault detection, effectively avoid false alarms and missed ground events, and can also increase the application scope of the corresponding detection device and improve the practicality of the detection device. In addition, the detection signal is adjusted based on the detection signal parameters to obtain the best detection signal, which can ensure that the loss of the detection signal during the transmission process is minimized, and the utilization rate of the detection signal is improved. The detection data is collected based on the loop structure of the circuit to be tested, so that comprehensive and accurate detection data can be collected, which ensures the integrity and accuracy of the data, and the detection signal is collected in the circuit to be tested. By setting detection points in the road, the correspondence between the detection points and the detection data can be obtained, and then the correlation between the detection data and the loop structure of the circuit to be tested can be obtained. By detecting the detection points in sequence according to the marking order, the source of the detection data can be quickly traced according to the marking order, and the traceability and positioning of the detection data can be achieved, which is helpful for analyzing the specific location of the grounding fault. Secondly, according to the correspondence between the detection points and the detection data, multiple detection data of the same detection point can be compared vertically to improve the stability of the detection data. Finally, fault analysis is performed on the collected detection data to determine the grounding loop in the circuit to be tested. The specific location of the grounding event in the circuit to be tested can be accurately analyzed, which significantly improves the accuracy of the detection results.

[0047] The above specific embodiments are preferred embodiments of the present invention, and are not intended to limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to the present specific embodiments. All equivalent changes made in accordance with the shape, structure, and method of the present invention are within the protection scope of the present invention.

Claims

1. A ground detection method based on signal injection technology, characterized in that: The method comprises the following steps: S1. Setting detection signal parameters based on historical operation data of the circuit to be tested, and generating a detection signal by a ground detection device based on a signal injection technology; S2, adjusting the detection signal based on the detection signal parameter to obtain an optimal detection signal, and inputting the optimal detection signal into the circuit to be tested; S3, after the optimal detection signal is input into the circuit to be tested, collecting detection data based on the loop structure of the circuit to be tested; S4. Performing a ground fault analysis based on the detection data, and determining a ground loop in the circuit to be tested according to a correspondence between the detection data and a loop structure of the circuit to be tested and a result of the ground fault analysis.

2. The ground detection method based on signal injection technology according to claim 1, characterized in that: In S1, the specific process of setting the detection signal parameters based on the historical operation data of the circuit to be tested is: S111, acquiring historical operation data of the circuit to be tested, and cleaning the historical operation data to obtain a complete data set; S112, extracting a frequency variation range, a current variation range, and a voltage variation range based on the complete data set; S113, setting a detection signal frequency range based on the frequency variation range, setting a detection signal current range based on the current variation range, and setting a detection signal voltage range based on the voltage variation range; S114, sorting out the detection signal frequency range, the detection signal current range and the detection signal voltage range to obtain detection signal parameters.

3. The ground detection method based on signal injection technology according to claim 1, characterized in that: In S2, the specific process of adjusting the detection signal based on the detection signal parameter to obtain the optimal detection signal is: adjusting the voltage of the detection signal based on the detection signal voltage range in the detection signal parameter, and determining that the detection signal corresponding to the voltage is a voltage-stabilized signal when the voltage is within the detection signal voltage range; Adjusting the current of the voltage stabilization signal based on the detection signal current range in the detection signal parameter, and determining that the voltage stabilization signal corresponding to the current is a current limiting signal when the current is within the detection signal current range; The frequency of the current limiting signal is adjusted based on the detection signal frequency range in the detection signal parameter, and when the frequency is within the detection signal frequency range, the frequency corresponding current limiting signal is determined to be the optimal detection signal.

4. The ground detection method based on signal injection technology according to claim 1, characterized in that: In S3, the specific process of collecting detection data based on the loop structure of the circuit to be tested is: S311, setting detection points based on the loop structure of the circuit to be tested, and sequentially marking the detection points to obtain a detection point set; S312 , detecting the detection points in the detection point set in sequence based on the marking order of the detection points to obtain detection data corresponding to the detection points, and arranging the detection data corresponding to the detection points to obtain detection data.

5. The ground detection method based on signal injection technology according to claim 1, characterized in that: In S4, the specific process of performing ground fault analysis based on the detection data is as follows: The detection data is compared with a preset fault threshold. If the detection data is greater than the preset fault threshold, it is determined that a grounding event has occurred in the circuit to be tested corresponding to the detection data, and the detection data greater than the preset fault threshold is marked as grounding fault data. If the detection data is less than or equal to the preset fault threshold, it is determined that a grounding event has not occurred in the circuit to be tested corresponding to the detection data.

6. The ground detection method based on signal injection technology according to claim 5, characterized in that: In S4, the specific process of determining the ground loop in the circuit to be tested according to the corresponding relationship between the detection data and the circuit loop structure to be tested and the result of the ground fault analysis is: S411, when the ground fault analysis result clearly indicates that a ground fault occurs in the circuit to be tested corresponding to the corresponding detection data, determining a fault detection point according to the ground fault data in the detection data and a detection point corresponding to the detection data; S412, determining the grounding loop according to the corresponding relationship between the detection point and the loop in the circuit to be tested and the fault detection point.

7. A grounding detection device based on signal injection technology, applicable to a grounding detection method based on signal injection technology as claimed in any one of claims 1 to 6, characterized in that: Including: signal generator, signal current clamp meter, coordination filter components; The signal generator is used to generate a detection signal, one end of the signal generator is grounded, and the other end is electrically connected to the input end of the coordination filter component; The coordination filter component is used to adjust the frequency of the detection signal, and the output end of the coordination filter component is electrically connected to the detection end of the circuit to be tested; the signal current clamp meter is used to detect whether there is a detection signal in the circuit to be tested, and the input end of the signal current clamp meter is electrically connected to the tested end of the circuit to be tested.

8. The ground detection device based on signal injection technology according to claim 7, characterized in that: The coordinated filtering components include: reactors, resistors, and capacitors; The input end of the reactor is electrically connected to the output end of the capacitor, the input end of the reactor is electrically connected to one end of the resistor, the other end of the resistor is electrically connected to the input end of the capacitor, the input end of the capacitor is electrically connected to the signal generator as the input end of the coordinated filtering component, and the output end of the reactor is electrically connected to the detection end of the circuit to be tested as the output end of the coordinated filtering component.

9. The ground detection device based on signal injection technology according to claim 8, characterized in that: The reactor is specifically a saturated reactor having a saturated structure.

10. The ground detection device based on signal injection technology according to claim 7, characterized in that: The signal generator includes: a protection module, a signal driving module, a power amplifier module, a voltage regulating module, and a field effect current limiting module; One end of the protection module is grounded, the other end of the protection module is electrically connected to the protection end of the voltage regulating module, the input end of the voltage regulating module is electrically connected to the output end of the power amplifier module, the input end of the power amplifier module is electrically connected to the output end of the signal driving module, the output end of the voltage regulating module is electrically connected to the input end of the field effect current limiting module, and the output end of the field effect current limiting module is electrically connected to the input end of the coordination filtering component.

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