Grounding detection device compatible with multiple line power grid systems

Abstract

The invention relates to a grounding detection device compatible with multiple line power grid systems. The grounding detection device comprises a grounding detection circuit and a signal processing circuit. The grounding detection circuit comprises a live wire detection port and a ground wire detection port; the live wire detection port is connected with live wires in different power grid systems, and the ground wire detection port is connected with ground wires in different power grid systems; the grounding detection circuit is connected with the signal processing circuit through a current transformer. The current of the live wire in the power grid system is detected through the live wire detection port, the current of the ground wire in the power grid system is detected through the ground wire detection port, and the signal processing circuit converts a current signal into a voltage signal according to the current of the live wire and the current of the ground wire and outputs the voltage between the live wire and the ground wire based on the voltage signal. The method is beneficial for being compatible with power grid systems of different lines, and solves the problem that the charging pile cannot work normally due to the fact that the charging pile cannot be compatible with the power grid systems of different lines and cannot accurately recognize the real grounding state and misreport a grounding fault.

Description

Technical Field

[0001] The present application relates to the field of circuit detection technology, and in particular to a grounding detection device compatible with multiple line power grid systems. Background Art

[0002] With the rapid development of China's new energy vehicle industry, an increasing number of domestically produced new energy vehicles are being exported to overseas markets such as Europe and America. Significant differences exist in power systems across different countries and regions, such as in power supply phase sequence, voltage levels, and grounding methods. This places higher demands on the electrical compatibility of electric vehicle charging stations.

[0003] In existing technology, AC charging stations for electric vehicles typically determine grounding status by detecting the voltage relationship between the live wire (L), neutral wire (N), and PE (ground wire). In a common L / N / PE power supply system, when the device is properly grounded and a 120V input voltage is applied, the voltage between the live wire (L) and the ground wire (PE) is typically 120V. If the device is not grounded, the voltage between the live wire and the ground wire drops to 0V. Therefore, this method can more accurately determine the grounding status.

[0004] However, in parts of Europe and America, AC power grids often use L / L / PE systems, or L / L / PE (with a center tap). In these systems, due to the prevalence of Y-capacitor ground coupling within the equipment, a voltage of approximately 120V may be measured between the live wire and the PE even if the PE ground wire is not connected. This phantom voltage can easily cause traditional detection circuits to mistakenly interpret a normal ground connection, or falsely report a ground fault when the ground connection is actually established, causing the charging station to malfunction.

[0005] Therefore, existing ground detection methods are not compatible with these various grid systems and cannot accurately identify the true grounding status under different grid conditions. In particular, the lack of a ground detection technology that can be applied to all three grid structures, L / N / PE, L / L / PE, and L / L / PE (center tap), has become a technical challenge that needs to be addressed in the global application of AC charging stations for electric vehicles. Summary of the Invention

[0006] The present application provides a grounding detection device that is compatible with multiple line power grid systems to solve the problem that the existing technology is unable to be compatible with different line power grid systems and cannot accurately identify the true grounding status under different power grid conditions, thereby falsely reporting a ground fault, which causes the charging pile to fail to work properly. The present application detects the current of the live wire in the power grid system through a live wire detection port, and detects the current of the ground wire in the power grid system through a ground wire detection port. The signal processing circuit converts the current signal into a voltage signal based on the current of the live wire and the current of the ground wire, and outputs the voltage between the live wire and the ground wire based on the voltage signal to determine whether different power grid systems are safely grounded. This is conducive to compatibility with power grid systems of different lines and accurately identifying the true grounding status under different power grid conditions, thereby avoiding false alarms.

[0007] In a first aspect, the present application provides a grounding detection device compatible with multiple line power grid systems, the device comprising a grounding detection circuit and a signal processing circuit;

[0008] The ground detection circuit includes a live wire detection port and a ground wire detection port;

[0009] The live wire detection port is connected to the live wire in different power grid systems, and the ground wire detection port is connected to the ground wire in different power grid systems;

[0010] The ground detection circuit is connected to the signal processing circuit via a current transformer;

[0011] The live wire detection port is used to detect the live wire current of the live wire;

[0012] The ground wire detection port is used to detect the ground wire current of the ground wire;

[0013] The signal processing circuit is used to convert the current signal into a voltage signal according to the live wire current and the ground wire current, and to determine whether the power grid system is safely grounded based on the voltage signal.

[0014] Optionally, the input end of the live wire detection port is connected to the live wire, and the output end is connected to the first input end of the current transformer;

[0015] The input end of the ground detection port is connected to the ground wire, and the output end is connected to the second input end of the current transformer;

[0016] The input end of the live wire detection port is responsive to the live wire current and transmits the live wire current to the first input end of the current transformer;

[0017] The first input terminal of the current transformer is responsive to the live current and transmits the live current to the first output terminal of the current transformer;

[0018] The input end of the ground detection port is responsive to the ground current and transmits the ground current to the second input end of the current transformer;

[0019] The second input terminal of the current transformer is responsive to the ground current and transmits the ground current to the second output terminal of the current transformer.

[0020] Optionally, the signal processing circuit includes an operational amplifier module, a voltage detection module and a processor module;

[0021] The first output terminal and the second output terminal of the current transformer are connected to the input terminal of the operational amplifier module;

[0022] The output end of the operational amplifier module is connected to the input end of the voltage detection module;

[0023] The output end of the voltage detection module is connected to the processor module;

[0024] The input end of the operational amplifier module responds to the live current and the ground current, converts the current signal into a voltage signal according to the live current and the ground current, and transmits the voltage signal to the processor module;

[0025] The processor module outputs a voltage value between the live wire and the ground wire in response to the voltage signal, and determines whether the power grid system is safely grounded based on the voltage value.

[0026] Optionally, the power grid system includes a first line, a second line and a third line;

[0027] The first circuit includes a live wire, a neutral wire, and a ground wire. When detecting the first circuit, the live wire detection port is connected to the live wire, and the ground wire detection port is connected to the ground wire.

[0028] The second circuit includes a first live wire, a second live wire and a ground wire. When detecting the second circuit, the live wire detection port is respectively adapted to be connected to the first live wire or the second live wire, and the ground wire detection port is connected to the ground wire.

[0029] The third circuit includes a first live wire, a second live wire and a middle tap. When detecting the third circuit, the live wire detection port is connected to the first live wire or the second live wire, and the ground wire detection port is connected to the middle tap.

[0030] Optionally, the voltage detection module includes a first sampling resistor and a second sampling resistor, the first sampling resistor responds to the live wire current, and the second sampling resistor responds to the ground wire current, converting the current signals of the live wire current and the ground wire current into voltage signals, wherein the voltage signal is a voltage difference signal between the live wire and the ground wire.

[0031] Optionally, the operational amplifier module includes a low-pass filtering unit, a reference voltage dividing unit, and an amplifying unit;

[0032] The input end of the low-pass filter unit is connected to the output end of the voltage detection module, and the output end is connected to the input end of the reference voltage dividing unit and the input end of the amplifying unit;

[0033] The output end of the reference voltage dividing unit is grounded;

[0034] The output end of the amplifying unit is connected to the processor module.

[0035] Optionally, the low-pass filtering unit includes a first low-pass filtering unit and a second low-pass filtering unit;

[0036] The first low-pass filtering unit includes a first resistor, a second resistor, a first capacitor, and a second capacitor.

[0037] Optionally, the reference voltage dividing unit includes a third resistor, a fourth resistor and a third capacitor.

[0038] Optionally, the amplifying unit includes a fifth resistor, a sixth resistor and an amplifier.

[0039] Optionally, the second low-pass filtering unit includes a seventh resistor and a fourth capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0042] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0043] Figure 1 A circuit diagram of a grounding detection device compatible with multiple line power grid systems provided in an embodiment of the present application;

[0044] Figure 2 Schematic diagram of a power grid system with three lines provided in an embodiment of the present application;

[0045] Figure 3 The power grid system provided in the embodiment of the present application is used as a circuit diagram inside the device. DETAILED DESCRIPTION

[0046] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0047] The disclosure below provides many different embodiments or examples for implementing different configurations of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0048] Figure 1 A circuit diagram of a ground detection device compatible with multiple line power grid systems provided in an embodiment of the present application, the device comprising a ground detection circuit and a signal processing circuit;

[0049] The ground detection circuit includes a live wire detection port and a ground wire detection port;

[0050] The live wire detection port is connected to the live wire in different power grid systems, and the ground wire detection port is connected to the ground wire in different power grid systems;

[0051] The ground detection circuit is connected to the signal processing circuit via a current transformer;

[0052] The live wire detection port is used to detect the live wire current of the live wire;

[0053] The ground wire detection port is used to detect the ground wire current of the ground wire;

[0054] The signal processing circuit is used to convert the current signal into a voltage signal according to the live wire current and the ground wire current, and to determine whether the power grid system is safely grounded based on the voltage signal.

[0055] Among them, the live wire (L) is provided by the power grid, and there is voltage (220V / 380V) between the carrier of AC power and the neutral wire or ground wire; the neutral wire (N) is the loop of the current circuit. During normal operation, it carries current but the voltage is 0V (reference ground). After disconnection, the live wire will float; the ground wire (PE) is a protective wire that does not carry normal operating current and provides safety protection for the current in the event of leakage.

[0056] like Figure 2 As shown, Figure 2 Schematic diagram of the power grid system with three lines provided in the embodiment of the present application. The electric vehicle AC charging pile usually determines the grounding status by detecting the voltage relationship between L (live wire), N (neutral wire) and PE (ground wire), where the power grid system types include L / N / PE, L / L / PE, and L / L / PE (with middle tap).

[0057] For example, in a common L / N / PE power supply system, when the device is properly grounded and a 120V input voltage is applied, the voltage between the live wire (L) and the ground wire (PE) is typically 120V. If the device is not grounded, the voltage between the live wire and the ground wire drops to 0V. Therefore, this method allows for a relatively accurate determination of the grounding status.

[0058] However, in parts of Europe and America, AC power grids often use L / L / PE power supply systems, or L / L / PE (with center tap) systems. Figure 3 As shown, Figure 3 The power grid system provided in the embodiments of the present application is used for circuit diagrams inside devices. In these systems, due to the widespread presence of Y capacitor-to-ground coupling within the devices, even if the PE ground wire is not connected, a voltage of approximately 120V may be measured between the live wire and the PE wire, and a voltage of approximately 120V may be measured between the PE wire and the neutral wire. The same is true for L / L / PE (with center tap) systems. Such virtual voltages can easily cause traditional detection circuits to misinterpret a normal ground connection, or misreport a ground fault when the ground connection is actually in effect, causing the charging station to malfunction.

[0059] In view of this, the present application provides a detection device that is compatible with three-line power grid systems by only connecting to the live wire and the ground wire. Under normal grounding conditions, it can accurately detect the voltage between the live wire and the ground wire, avoiding false alarms as grounding faults in the actual grounding state, which may cause the charging pile to fail to work normally.

[0060] Furthermore, the input end of the live wire detection port is connected to the live wire, and the output end is connected to the first input end of the current transformer;

[0061] The input end of the ground detection port is connected to the ground wire, and the output end is connected to the second input end of the current transformer;

[0062] The input end of the live wire detection port is responsive to the live wire current and transmits the live wire current to the first input end of the current transformer;

[0063] The first input terminal of the current transformer is responsive to the live current and transmits the live current to the first output terminal of the current transformer;

[0064] The input end of the ground detection port is responsive to the ground current and transmits the ground current to the second input end of the current transformer;

[0065] The second input terminal of the current transformer is responsive to the ground current and transmits the ground current to the second output terminal of the current transformer.

[0066] In the embodiments of this application, Figure 1 As shown, the circuit included in the device is divided into two parts. The currents of the live wire and the ground wire detected by the detection circuit are transmitted to the signal processing circuit through the current transformer. The detection circuit includes a sensing module. The sensing module includes four resistors R11, R12, R21, and R22. The currents of the live wire and the ground wire are sensed through the four resistors. The current transformer includes four terminals 1 (first input terminal), 2 (second input terminal), 3 (first output terminal), and 4 (second output terminal). Terminals 1 and 2 respond to the current of the live wire and the current of the ground wire, and transmit the current to terminals 3 and 4. Terminals 3 and 4 respond to the current of the live wire and the current of the ground wire and transmit the current to the signal processing circuit.

[0067] Furthermore, the signal processing circuit includes an operational amplifier module, a voltage detection module and a processor module;

[0068] The first output terminal and the second output terminal of the current transformer are connected to the input terminal of the operational amplifier module;

[0069] The output end of the operational amplifier module is connected to the input end of the voltage detection module;

[0070] The output end of the voltage detection module is connected to the processor module;

[0071] The input end of the operational amplifier module responds to the live current and the ground current, converts the current signal into a voltage signal according to the live current and the ground current, and transmits the voltage signal to the processor module;

[0072] The processor module outputs a voltage value between the live wire and the ground wire in response to the voltage signal, and determines whether the power grid system is safely grounded based on the voltage value.

[0073] Furthermore, the voltage detection module includes a first sampling resistor and a second sampling resistor, the first sampling resistor responds to the live wire current, and the second sampling resistor responds to the ground wire current, converting the current signals of the live wire current and the ground wire current into voltage signals, wherein the voltage signal is a voltage difference signal between the live wire and the ground wire.

[0074] In an embodiment of the present application, the signal processing circuit includes a voltage detection module, an operational amplifier module, and a processor module. The voltage detection module converts the current signal into a voltage signal via sampling resistors R1 and R2, and transmits the voltage signal to the operational amplifier module. The operational amplifier module amplifies the voltage signal before transmitting it to the processor module. The processor module calculates the output voltage value, which is the voltage between the live wire and the ground wire. The voltage value is used to determine whether the power grid system is securely grounded.

[0075] In this application, the detection circuit for detecting the live wire and the ground wire uses current detection instead of voltage detection, and then converts the current signal into a voltage signal in the signal processing circuit. The reason for using current detection instead of voltage detection is that the traditional scheme directly measures the L-PE voltage, which is easily affected by the Y capacitor. The present invention instead detects the live wire current and the ground wire current, and indirectly characterizes the grounding state through the current difference, thereby avoiding misjudgment caused by capacitive coupling.

[0076] Furthermore, the power grid system includes a first line, a second line and a third line;

[0077] The first circuit includes a live wire, a neutral wire, and a ground wire. When detecting the first circuit, the live wire detection port is connected to the live wire, and the ground wire detection port is connected to the ground wire.

[0078] The second circuit includes a first live wire, a second live wire and a ground wire. When detecting the second circuit, the live wire detection port is respectively adapted to be connected to the first live wire or the second live wire, and the ground wire detection port is connected to the ground wire.

[0079] The third circuit includes a first live wire, a second live wire and a middle tap. When detecting the third circuit, the live wire detection port is connected to the first live wire or the second live wire, and the ground wire detection port is connected to the middle tap.

[0080] In embodiments of the present application, the circuit can be used to detect three power grid systems. In one possible implementation, the live wire detection port is connected to the live wire L in the American L / N / PE power grid system. In another possible implementation, the live wire detection port is connected to any live wire L in the European L / L / PE power grid system. In yet another possible implementation, the live wire detection port is connected to any live wire L in the L / L / PE (center tap) power grid system. The ground wire detection port is connected to the ground wire PE in the L / N / PE power grid system. In another possible implementation, the ground wire detection port is connected to the ground wire PE in the L / L / PE power grid system. In yet another possible implementation, the ground wire detection port is connected to the ground wire PE in the L / L / PE (center tap) power grid system.

[0081] In the embodiment of the present application, according to the three power grid systems, under the condition of good grounding, there is a common characteristic that there is a voltage between L1 and PE. When the grounding line is broken, the voltage between L1 and PE is close to 0V. The specific data of the three power grid systems are shown in Table 1.

[0082]

[0083] Table 1

[0084] It can be seen from Table 1 that the grounding condition of the power grid system is detected by the circuit of the present application. When the grounding is disconnected, the voltage between the live wire and the ground wire of the three circuit systems is 0V. There is no situation in the prior art where there is still voltage between the live wire and the ground wire due to the presence of the Y capacitor. This is beneficial to avoid causing the traditional detection circuit to misjudge that the grounding is normal, or to misreport a grounding fault in the actual grounding state, thereby causing the charging pile to fail to work normally.

[0085] Furthermore, the operational amplifier module includes a low-pass filtering unit, a reference voltage dividing unit, and an amplifying unit;

[0086] The input end of the low-pass filter unit is connected to the output end of the voltage detection module, and the output end is connected to the input end of the reference voltage dividing unit and the input end of the amplifying unit;

[0087] The output end of the reference voltage dividing unit is grounded;

[0088] The output end of the amplifying unit is connected to the processor module.

[0089] In an embodiment of the present application, the operational amplifier module also includes a fifth capacitor C5, which is used to filter the signal so that the signal is transmitted to the low-pass filtering unit. The low-pass filtering unit filters the signal and transmits it to the amplification unit. At the same time, the reference voltage divider unit divides the voltage to protect the electrical equipment. The amplification unit transmits the amplified signal to the processor module to output the voltage value.

[0090] Furthermore, the low-pass filtering unit includes a first low-pass filtering unit and a second low-pass filtering unit;

[0091] The first low-pass filtering unit includes a first resistor, a second resistor, a first capacitor, and a second capacitor.

[0092] In an embodiment of the present application, a low-pass filtering unit is added before the analog signal is sent to the ADC before ADC sampling in order to prevent aliasing distortion caused by high-frequency components. In the present application, a low-pass filtering unit is formed by a first resistor R1, a second resistor R2, a first capacitor C1 and a second capacitor C2.

[0093] Furthermore, the reference voltage dividing unit includes a third resistor, a fourth resistor and a third capacitor.

[0094] In the embodiment of the present application, the reference voltage dividing unit divides the input voltage into a smaller voltage in proportion to protect circuits and electrical equipment. The reference voltage dividing unit includes a third resistor R3, a fourth resistor R4 and a third capacitor C3.

[0095] Furthermore, the amplifying unit includes a fifth resistor, a sixth resistor and an amplifier.

[0096] In the embodiment of the present application, the operational amplifier U1 refers to the process of achieving precise amplification, calculation or conversion of the input signal through the operational amplifier and circuit structure. The amplification unit includes a fifth resistor R5, a sixth resistor R6 and the amplifier U1.

[0097] Furthermore, the second low-pass filtering unit includes a seventh resistor and a fourth capacitor.

[0098] In the embodiment of the present application, after the voltage signal passes through the amplification unit, it also needs to pass through a second low-pass filtering unit before being input to the processor module to filter the signal again. This helps reduce the signal noise input to the processor module and enables the processor module to output a more accurate voltage value. The second low-pass filtering unit includes a seventh resistor R7 and a fourth capacitor C4.

[0099] In this embodiment of the present application, the operational amplifier module employs a dual-channel low-pass filter design, capable of processing the current channels of the live and ground wires separately, improving the stability of the voltage output. The reference voltage divider unit sets the reference voltage, which, combined with the bias structure of the amplifier unit, ensures that the signal output is within the effective recognition range. The processor module can set a warning threshold, triggering an alarm signal or power-off command when it detects that the voltage difference between the live and ground wires exceeds the safe range.

[0100] Compared with the existing technology, the present invention has the following beneficial effects: it is adaptable to various power grid structures and realizes a highly universal grounding detection function through different wiring methods; it uses current transformers to realize current sensing of the live wire and the ground wire, with high detection accuracy; the operational amplifier module combines filtering, voltage division and amplification functions to effectively improve signal processing capabilities and enhance system stability; the judgment logic is based on voltage difference output, with a fast response speed, and is suitable for actual power safety monitoring systems.

[0101] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0102] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0103] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0104] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0105] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0106] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of the above-mentioned various method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0107] The present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed through a computer program product. When the computer program product is run on a terminal device, the terminal device can implement the steps in the above-mentioned method embodiments when executing.

[0108] The above embodiments are intended only to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the above embodiments or replace some of the technical features therein with equivalents; and such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application and should be included within the scope of protection of the present application.

Claims

1. A ground detection device compatible with multiple line power grid systems, the device comprising a ground detection circuit and a signal processing circuit; The ground detection circuit includes a live wire detection port and a ground wire detection port; The live wire detection port is connected to the live wire in different power grid systems, and the ground wire detection port is connected to the ground wire in different power grid systems; The ground detection circuit is connected to the signal processing circuit via a current transformer; The live wire detection port is used to detect the live wire current of the live wire; The ground wire detection port is used to detect the ground wire current of the ground wire; The signal processing circuit is used to convert the current signal into a voltage signal according to the live wire current and the ground wire current, and to determine whether the power grid system is safely grounded based on the voltage signal.

2. The grounding detection device according to claim 1, characterized in that: The input end of the live wire detection port is connected to the live wire, and the output end is connected to the first input end of the current transformer; The input end of the ground detection port is connected to the ground wire, and the output end is connected to the second input end of the current transformer; The input end of the live wire detection port is responsive to the live wire current and transmits the live wire current to the first input end of the current transformer; The first input terminal of the current transformer is responsive to the live current and transmits the live current to the first output terminal of the current transformer; The input end of the ground detection port is responsive to the ground current and transmits the ground current to the second input end of the current transformer; The second input terminal of the current transformer is responsive to the ground current and transmits the ground current to the second output terminal of the current transformer.

3. The grounding detection device according to claim 2, characterized in that: The signal processing circuit includes an operational amplifier module, a voltage detection module and a processor module; The first output terminal and the second output terminal of the current transformer are connected to the input terminal of the operational amplifier module; The output end of the operational amplifier module is connected to the input end of the voltage detection module; The output end of the voltage detection module is connected to the processor module; The input end of the operational amplifier module responds to the live current and the ground current, converts the current signal into a voltage signal according to the live current and the ground current, and transmits the voltage signal to the processor module; The processor module outputs a voltage value between the live wire and the ground wire in response to the voltage signal, and determines whether the power grid system is safely grounded based on the voltage value.

4. The grounding detection device according to any one of claims 1 to 3, characterized in that: The power grid system includes a first line, a second line and a third line; The first circuit includes a live wire, a neutral wire, and a ground wire. When detecting the first circuit, the live wire detection port is connected to the live wire, and the ground wire detection port is connected to the ground wire. The second circuit includes a first live wire, a second live wire and a ground wire. When detecting the second circuit, the live wire detection port is respectively adapted to be connected to the first live wire or the second live wire, and the ground wire detection port is connected to the ground wire. The third circuit includes a first live wire, a second live wire and a middle tap. When detecting the third circuit, the live wire detection port is connected to the first live wire or the second live wire, and the ground wire detection port is connected to the middle tap.

5. The grounding detection device according to claim 3, characterized in that: The voltage detection module includes a first sampling resistor and a second sampling resistor, wherein the first sampling resistor responds to the live wire current, and the second sampling resistor responds to the ground wire current, and converts the current signals of the live wire current and the ground wire current into a voltage signal, wherein the voltage signal is a voltage difference signal between the live wire and the ground wire.

6. The grounding detection device according to claim 5, characterized in that: The operational amplifier module includes a low-pass filtering unit, a reference voltage dividing unit, and an amplifying unit; The input end of the low-pass filter unit is connected to the output end of the voltage detection module, and the output end is connected to the input end of the reference voltage dividing unit and the input end of the amplifying unit; The output end of the reference voltage dividing unit is grounded; The output end of the amplifying unit is connected to the processor module.

7. The grounding detection device according to claim 6, characterized in that: The low-pass filtering unit includes a first low-pass filtering unit and a second low-pass filtering unit; The first low-pass filtering unit includes a first resistor, a second resistor, a first capacitor, and a second capacitor.

8. The grounding detection device according to claim 6, characterized in that: The reference voltage dividing unit includes a third resistor, a fourth resistor and a third capacitor.

9. The grounding detection device according to claim 6, characterized in that: The amplifying unit includes a fifth resistor, a sixth resistor and an amplifier.

10. The grounding detection device according to claim 7, characterized in that: The second low-pass filtering unit includes a seventh resistor and a fourth capacitor.

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