Ground wire disconnection fault on-line detection system and detection method

Abstract

The invention relates to a ground wire disconnection fault on-line detection system which is characterized by comprising an easy oscillation circuit which is electrically connected with a ground point and is used for being in an oscillation state according to disconnection between the ground point and the ground and being in a stable state according to good connection between the ground point and the ground; the oscillation detection circuit is electrically connected with the easy oscillation circuit and is used for detecting the circuit state of the easy oscillation circuit; the indication circuit is electrically connected with the oscillation detection circuit and is used for indicating a detection result of the oscillation detection circuit; and the power supply switch power supply module is electrically connected with the easy oscillation circuit, the oscillation detection circuit and the indication circuit, and is used for converting the input power frequency alternating current into direct current and supplying power to the easy oscillation circuit, the oscillation detection circuit and the indication circuit. Other test cables are not introduced, the grounding state of the grounding wire is judged according to the state of the easy-to-oscillate circuit by utilizing the anti-interference characteristic of the grounding wire, and the device has the characteristics of simple structure and high detection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular to an online detection system and method for ground wire disconnection fault. Background Art

[0002] Equipment grounding is one of the important measures for electrical safety and normal operation of power systems. It has the following features: ① Safety protection: When electrical equipment fails, such as insulation damage causing the casing to be energized, grounding can quickly guide the leakage current to the ground, triggering the action of the protection device (such as the circuit breaker), cutting off the power supply, and preventing electric shock accidents. ② Stabilizing voltage: In the power system, grounding can provide a stable reference potential for the system, which helps to maintain voltage stability. ③ Reducing interference: Grounding can reduce the impact of electromagnetic interference on electrical equipment and improve the anti-interference ability of the system. ④ Preventing lightning strikes: In thunderstorm weather, the grounding system can effectively guide lightning current into the ground to protect the equipment from damage. ⑤ Improving system reliability: In some power systems, grounding can improve system reliability. For example, when the neutral point of the transformer is grounded, it can reduce the damage caused by a single-phase grounding fault. ⑥ Signal reference: In communication and data processing systems, grounding provides a common reference point, which helps to transmit signals stably. ⑦ Preventing corrosion: For metal equipment, proper grounding can reduce corrosion caused by electrochemical action. ⑧ Fault location: In some cases, the grounding system can help locate the fault point, which is convenient for maintenance and troubleshooting. ⑨. Static discharge: Grounding is a necessary option in anti-static wrist strap socket, anti-static desktop and anti-static tool grounding.

[0003] At present, the detection of grounding conditions can be carried out by periodic detection or real-time online detection of grounding resistance. The implementation principles of real-time monitoring equipment for grounding resistance usually include non-contact online testing of grounding resistance and contact online testing of grounding resistance. The principle of non-contact is to measure the grounding resistance of the grounding loop through the principle of current transformer. The measured grounding resistance needs to form a loop, or an auxiliary lead is used to form a loop. The resistance measurement range is usually around 0.01Ω to 200Ω. The contact online grounding resistance detector measures the resistance between the equipment grounding point and the remote grounding point through the principle of 2-wire, 3-wire or 4-wire method.

[0004] The above two types of grounding resistance online monitoring equipment are usually large in size and are additional equipment independent of the grounding equipment. If each grounding equipment is equipped with a grounding resistance online monitor, it will occupy a large volume. If the wired measurement principle is used, each device needs to be equipped with a wire to connect to the remote grounding point.

[0005] At the same time, there are some application scenarios, such as grounding of anti-static monitoring equipment in anti-static areas and signal reference ground, where the ground wire mainly serves as a static discharge path, anti-interference, signal reference and improving system reliability. When there are many devices in the work area, the ground wire network is more complicated, and there are many connection points between the ground wire networks, which can easily cause breakage and looseness. Therefore, the size of the grounding resistance in these occasions is not the most important concern, but whether the ground wire is disconnected is the primary issue that needs to be monitored.

[0006] Therefore, there is an urgent need to provide an online detection device for ground wire disconnection fault. Summary of the invention

[0007] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an online detection system and method for ground wire disconnection fault, which has the characteristics of simple structure and high detection efficiency.

[0008] To achieve the above-mentioned purpose, the present invention provides an online detection system for grounding line disconnection fault, comprising:

[0009] an easy-oscillation circuit, electrically connected to the grounding point, for being in an oscillating state when the grounding point is disconnected from the ground, and being in a stable state when the grounding point is well connected to the ground;

[0010] an oscillation detection circuit, electrically connected to the easy-oscillation circuit, and used to detect a circuit state of the easy-oscillation circuit;

[0011] an indicating circuit, electrically connected to the oscillation detection circuit, and used for indicating a detection result of the oscillation detection circuit;

[0012] The power supply switch power supply module is electrically connected to the easy-oscillation circuit, the oscillation detection circuit and the indication circuit, and is used to convert the input industrial frequency alternating current into direct current and supply power to the easy-oscillation circuit, the oscillation detection circuit and the indication circuit.

[0013] According to a technical solution of the present invention, the easy-oscillation circuit comprises:

[0014] A first resistor and a second resistor connected in series, wherein a first end of the first resistor is electrically connected to the positive electrode of the power supply switch power supply module; a second end of the first resistor is electrically connected to a first end of the second resistor, and a second end of the second resistor is electrically connected to the grounding point;

[0015] A flying lead, a first end of which is electrically connected to the positive electrode of the power supply module of the power supply switch;

[0016] A third resistor and a fourth resistor connected in series, wherein a first end of the third resistor is electrically connected to a second end of the flying lead, a second end of the third resistor is electrically connected to a first end of the fourth resistor, and a second end of the fourth resistor is electrically connected to a negative electrode of the power supply switch power supply module;

[0017] The comparison amplifier element is an operational amplifier or a comparator, whose non-inverting input terminal is electrically connected to the second end of the first resistor, whose inverting input terminal is electrically connected to the second end of the third resistor, and whose output terminal outputs a signal S1; whose positive and negative power supply terminals are electrically connected to the positive and negative electrodes of the power supply switch power supply module respectively;

[0018] a fifth resistor and a sixth resistor connected in series, wherein a first end of the fifth resistor is electrically connected to the output end of the operational amplifier, a second end of the fifth resistor is electrically connected to a first end of the sixth resistor, and a second end of the sixth resistor is connected to a negative electrode of the power supply switch power supply module; and a second end of the fifth resistor outputs a signal S2;

[0019] The first resistor and the second resistor are low-value resistors, and their resistance values ​​are both less than 10 kΩ. The third resistor and the fourth resistor are high-value resistors, and their resistance values ​​are both greater than 1 GΩ.

[0020] According to a technical solution of the present invention, the oscillation detection circuit detects the circuit state of the easy-to-oscillate circuit by detecting the count value per unit time of the AC signal in the easy-to-oscillate circuit. The oscillation detection circuit includes a digital processor for receiving the signal S2 from the easy-to-oscillate circuit and outputting an oscillation detection result output signal S3.

[0021] According to a technical solution of the present invention, the oscillation detection circuit detects the circuit state of the easy-to-oscillate circuit by detecting the AC signal component in the easy-to-oscillate circuit. The oscillation detection circuit includes:

[0022] A first capacitor, a first end of which is used to receive the signal S2;

[0023] A first diode, whose anode is electrically connected to the second end of the first capacitor; and whose cathode outputs an oscillation detection result signal S3;

[0024] a second diode, a cathode of which is electrically connected to the second end of the first capacitor, and an anode of which is electrically connected to the negative electrode of the power supply switch power supply module;

[0025] The filtering circuit includes a second capacitor and a seventh resistor, wherein the first ends of the second capacitor and the seventh resistor are electrically connected to the cathode of the first diode, and the second ends of the second capacitor and the seventh resistor are electrically connected and electrically connected to the negative electrode of the power supply switch power supply module.

[0026] According to a technical solution of the present invention, the indication circuit includes:

[0027] A signal driving circuit, whose input end is used to receive the oscillation detection result output signal S3;

[0028] The sound and light indication circuit has an input end electrically connected to the output end of the signal driving circuit and is used to send out an alarm signal according to the driving signal; the sound and light indication circuit can be a buzzer or a light emitting diode.

[0029] According to one aspect of the present invention, a detection method based on the above-mentioned ground wire disconnection fault online detection system is provided, which specifically comprises the following steps:

[0030] Step S1, the industrial frequency alternating current supplies power to the easy-oscillation circuit, the oscillation detection circuit and the indication circuit through the power supply switch power supply module;

[0031] Step S2, detecting the state of the easy-to-oscillate circuit by means of the oscillation detection circuit;

[0032] Step S3: If the grounding point is well grounded, the oscillation detection circuit detects that the easy-to-oscillate circuit is in a stable state, and the indication circuit generates a good grounding indication signal; if the grounding point is disconnected from the ground, the oscillation detection circuit detects that the easy-to-oscillate circuit is in an oscillating state, and the indication circuit generates a poor grounding indication signal.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] Compared with periodic calibration and real-time online monitoring equipment for ground resistance, this solution does not require the connection of additional test wires, but only requires the connection of the ground wire to be measured. This solution utilizes the interference suppression characteristics of the ground wire. The ground wire to be measured is connected to the test circuit. The test circuit has two states, one is a stable state and the other is an unstable state. When the ground wire is normally connected to the ground, the ground wire plays an interference suppression role, and the test circuit is in a stable state; when the ground wire is not connected to the ground, the ground wire has no interference suppression effect, and the test circuit is in an unstable state. By observing the different states of the test circuit, it is possible to determine whether the ground wire is well connected to the ground, and when a disconnection fault occurs, an alarm is triggered. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A schematic diagram showing the structure of a ground wire disconnection fault online detection system according to an embodiment of the present invention;

[0037] Figure 2 A schematic diagram showing the structure of an easy-oscillation circuit provided according to an embodiment of the present invention;

[0038] Figure 3 A schematic diagram schematically shows the structure of an oscillation detection circuit provided according to an embodiment of the present invention;

[0039] Figure 4 A schematic diagram schematically shows the structure of an oscillation detection circuit provided according to another embodiment of the present invention;

[0040] Figure 5 The figure schematically shows the structure of an indication circuit provided according to an embodiment of the present invention.

[0041] The corresponding relationship between the reference numerals and component names is as follows:

[0042] 1. Easy oscillation circuit; 2. Oscillation detection circuit; 3. Indication circuit; 4. Power supply switch power supply module. DETAILED DESCRIPTION

[0043] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0044] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0045] like Figure 1 As shown, the present invention provides an online detection system for grounding wire disconnection fault, comprising:

[0046] The easy-oscillation circuit 1 is electrically connected to the grounding point, and is used to be in an oscillating state when the grounding point is disconnected from the ground, and in a stable state when the grounding point is well connected to the ground;

[0047] An oscillation detection circuit 2, electrically connected to the easy oscillation circuit 1, for detecting the circuit state of the easy oscillation circuit 1;

[0048] An indication circuit 3, electrically connected to the oscillation detection circuit 2, and used for indicating the detection result of the oscillation detection circuit 2;

[0049] The power supply switch power supply module 4 is electrically connected to the easy-oscillation circuit 1, the oscillation detection circuit 2 and the indication circuit 3, and is used to convert the input industrial frequency AC current into DC current and supply power to the easy-oscillation circuit 1, the oscillation detection circuit 2 and the indication circuit 3.

[0050] The principle of the present invention is as follows:

[0051] The system provided by the present invention is mainly composed of an easy-to-oscillate circuit 1, a power switch power module 4, an external grounding point G1, an oscillation detection circuit 2 and an indication circuit 3. If the grounding point G1 is disconnected from the ground, the easy-to-oscillate circuit 1 is powered by the power switch power module 4, introducing interference, so that the easy-to-oscillate circuit 1 is in an oscillating state. If the grounding point G1 is well connected to the ground, the ground wire has the anti-interference property, and the easy-to-oscillate circuit 1 is in a stable state. By detecting the difference between the two states using the oscillation detection circuit 2, it is possible to determine whether the grounding point G1 is well connected to the ground, and the test result is indicated by the indication circuit 3.

[0052] In the present invention, the grounding point G1 is connected to the earth through a grounding wire. The power input of the detection system is industrial frequency AC power, which is 220VAC in my country and 110VAC in some other countries. The industrial frequency AC power outputs DC through the power supply switch power supply module 4 for use by all other circuits. The 0 potential end of the power supply switch power supply module 4, that is, the reference end, is not connected to the ground wire of the three-core power input wire from the inside, that is, the output reference end of the power supply switch power supply module 4 is isolated from the ground wire of the power input.

[0053] The grounding wire is introduced from G1 and connected to a designated point of the easy-to-oscillate circuit 1, which is usually the reference end of the power supply switch power supply module 4. Of course, it can also be designed to be another point.

[0054] When the grounding point G1 is well electrically connected to the earth, the easy-to-oscillate circuit 1 is in a stable state, and the output signal is a stable DC signal. When the grounding point G1 is not electrically connected to the earth, the easy-to-oscillate circuit 1 is in an oscillating state, and the output signal is an AC signal with oscillating amplitude.

[0055] The oscillation detection circuit 2 can have multiple modes. The first mode is to detect the AC signal component in the signal. The AC component of the DC signal is 0, and the AC component of the AC signal is significantly greater than 0. The second mode is a counter. The AC signal is shaped into an AC signal with a suitable amplitude by a comparator or an operational amplifier, and then passes through a counter. The count value per unit time is significantly greater than 0. After the DC signal is shaped by the comparator, it is still a DC signal, and the count value per unit time is basically equal to 0.

[0056] The result of the oscillation detection circuit 2 needs to be identified and indicated. If it is judged that the grounding is not good, an alarm is given through sound and light when necessary.

[0057] The input of the easy oscillation circuit 1 includes the grounding point G1 and the positive and negative poles of the power supply switch power supply module 4, and its output is a signal. This signal is connected to the oscillation detection circuit 2 as an input. The characteristic of the easy oscillation circuit is that when the grounding point G1 is electrically disconnected from the ground, the output signal is in an oscillating state, and the oscillating state is that the signal continuously jumps between the upper and lower amplitudes. When the grounding point G1 is reliably electrically connected to the ground, the output signal is in a stable state, and the stable state is that the signal basically maintains a constant amplitude. There are many ways to implement an oscillation circuit, and the following example illustrates one of them.

[0058] like Figure 2 As shown, in one embodiment of the present invention, the easy oscillation circuit 1 includes:

[0059] A first resistor R1 and a second resistor R2 are connected in series, wherein a first end of the first resistor R1 is electrically connected to the positive electrode of the power supply switch power supply module 4; a second end of the first resistor R1 is electrically connected to a first end of the second resistor R2, and a second end of the second resistor R2 is electrically connected to a ground point;

[0060] A flying lead L1, a first end of which is electrically connected to the positive electrode of the power supply switch power supply module 4;

[0061] A third resistor R3 and a fourth resistor R4 are connected in series, a first end of the third resistor R3 is electrically connected to the second end of the flying wire L1, a second end of the third resistor R3 is electrically connected to the first end of the fourth resistor R4, and a second end of the fourth resistor R4 is electrically connected to the negative electrode of the power supply switch power supply module 4;

[0062] The comparison amplifier element A1 is an operational amplifier or a comparator, whose non-inverting input terminal is electrically connected to the second end of the first resistor R1, whose inverting input terminal is electrically connected to the second end of the third resistor R3, and whose output terminal outputs the signal S1; whose positive power supply terminal and negative power supply terminal are electrically connected to the positive electrode and negative electrode of the power supply switch power supply module 4 respectively;

[0063] A fifth resistor R5 and a sixth resistor R6 are connected in series, a first end of the fifth resistor R5 is electrically connected to the output end of the operational amplifier, a second end of the fifth resistor R5 is electrically connected to the first end of the sixth resistor R6, and a second end of the sixth resistor R6 is connected to the negative electrode of the power supply switch module 4; a second end of the fifth resistor R5 outputs a signal S2;

[0064] The first resistor R1 and the second resistor R2 are low-value resistors, and their resistances are both less than 10 kΩ. The third resistor R3 and the fourth resistor R4 are high-value resistors, and their resistances are both greater than 1 GΩ.

[0065] Among them, the grounding point G1 is connected to the earth, and the positive and negative signals of the power supply switch power supply module 4 are VCC and POW_GND respectively. The basic principle of the circuit is that the operational amplifier compares the voltage values ​​of V1 and V2. The circuit is designed so that the theoretical calculated values ​​of V1 and V2 are close, wherein the theoretical calculated value V1 is greater than V2. According to the theoretical calculated value analysis, the output signal S should be a high level, close to the amplitude of VCC. The signal S1 is converted to a level through the voltage divider of R5 and R6, and is directly received by the oscillation detection circuit 2.

[0066] The input resistance of the comparison amplifier element A1 is selected to be relatively large, generally greater than 1TΩ. The voltage-dividing resistors R1 and R2 are low-value resistors, both of which are less than 10kΩ. The voltage V1 after they divide the voltage is not easily disturbed and maintains a relatively stable value. The third resistor R3 and the fourth resistor R4 are voltage-dividing resistors, both of which are high-value resistors, both of which are greater than 1GΩ. The voltage V2 after they divide the voltage is easily disturbed and fluctuates. In addition, according to the needs of the actual debugging effect, a section of flying wire L1 can be introduced to increase the probability or degree of interference with V2. When the signal V2 fluctuates, the value of V2 is sometimes smaller than V1, and sometimes larger than V1. After comparison by A1, the signal S1 jumps between the high level and the low level, resulting in an oscillating state. Signal S2 also jumps between the digital level of 0 and 1.

[0067] By reasonably selecting the component models and parameters of the above circuit, when the ground point G1 is well connected to the ground GND, the ground GND has a suppressive effect on the interference introduced by the power supply VCC and POW_GND, and the output signal S2 maintains a stable level state (a high level in this embodiment). When the ground point G1 is disconnected from the ground GND, the ground GND cannot suppress the interference introduced by the power supply VCC and POW_GND, and the output signal S2 maintains an oscillating level state.

[0068] According to one embodiment of the present invention, Figure 3 As shown, the oscillation detection circuit 2 includes: a digital processor, which is used to receive the signal S2 from the easy-oscillation circuit and output an oscillation detection result output signal S3.

[0069] Among them, the input of the oscillation detection circuit 2 is the output signal S2 of the previous stage, and the signal S2 can be directly connected to the pin of the digital signal processor, and the digital signal processor can be a chip with counting function and logic operation function such as a single-chip microcomputer, DSP, CPLD or FPGA. The digital signal processor distinguishes whether the upper circuit oscillates by calculating the number of high and low level jumps of the input signal, and then outputs the oscillation detection result output signal S3. When it is judged that the previous stage circuit is in an oscillating state, S3 outputs a high level, and when it is judged that the previous stage circuit is in a stable state, S3 outputs a low level.

[0070] In another embodiment of the present invention, Figure 4 As shown, the oscillation detection circuit 2 includes:

[0071] A first capacitor C1, a first end of which is used to receive a signal S2; the first capacitor C1 is a DC blocking capacitor;

[0072] A first diode D1, whose anode is electrically connected to the second end of the first capacitor C1; whose cathode outputs an oscillation detection result output signal S3;

[0073] A second diode D2, a cathode of which is electrically connected to the second end of the first capacitor C1, and an anode of which is electrically connected to the negative electrode of the power supply switch power supply module;

[0074] The filtering circuit includes a second capacitor C2 and a seventh resistor R7, wherein the first ends of the second capacitor C2 and the seventh resistor R7 are electrically connected to the cathode of the first diode D1, and the second ends of the second capacitor C2 and the seventh resistor R7 are electrically connected to the cathode of the power supply switch power supply module.

[0075] The AC component of the detection signal S2 is used to determine whether the detection signal S2 oscillates. The DC isolation capacitor C1 isolates the DC signal from being transmitted to the next stage, allowing the AC signal to pass through, and then rectified by the first diode D1, so that the oscillation detection result output signal S3 presents a voltage signal of a certain amplitude.

[0076] If S2 is a DC signal, the voltage of the oscillation detection result output signal S3 is always 0. If S2 is an oscillating signal, it contains an AC component and S3 presents a voltage of a certain amplitude. Therefore, according to the two states of the signal S3, it can be distinguished whether the front-stage output signal S2 is an oscillating signal. The output signal S3 can indicate to the back-stage indication circuit whether the circuit state is a stable state or an oscillating state.

[0077] In one embodiment of the present invention, Figure 4 As shown, the indicating circuit 3 includes:

[0078] A signal driving circuit, whose input end is used to receive the signal S3;

[0079] The sound and light indication circuit has an input end electrically connected to the output end of the signal driving circuit, and is used to send out an alarm signal according to the driving signal; the sound and light indication circuit can be a buzzer and / or a light emitting diode.

[0080] The function of the indication circuit 3 is to indicate when the easy-oscillation circuit 1 is in an oscillation state by means of light-emitting diodes lighting up and buzzer alarming; and to indicate when the easy-oscillation circuit 1 is in a stable state by means of a green light.

[0081] The input of the indication circuit 3 is the oscillation detection output signal S3. When S3 is at a low level, it indicates that the easy oscillation circuit 1 is in a stable state. When S3 is at a high level, it indicates that the easy oscillation circuit 1 is in an oscillating state, which can trigger the sound and light alarm of the subsequent stage. The signal driving circuit can enhance the driving ability of the signal S3 to drive the sound and light indication circuit of the subsequent stage.

[0082] The present invention provides a detection method based on the above-mentioned ground wire disconnection fault online detection system, which specifically includes the following steps:

[0083] Step S1, the industrial frequency alternating current supplies power to the easy-to-oscillate circuit 1, the oscillation detection circuit 2 and the indication circuit 3 through the power supply switch power supply module 4;

[0084] Step S2, detecting the state of the easy-to-oscillate circuit 1 by the oscillation detection circuit 2;

[0085] Step S3, if the grounding point is well grounded, the oscillation detection circuit 2 detects that the easy-to-oscillate circuit 1 is in a stable state, and the indication circuit 3 generates a good grounding indication signal; if the grounding point is disconnected from the ground, the oscillation detection circuit 2 detects that the easy-to-oscillate circuit 1 is in an oscillating state, and the indication circuit 3 generates a poor grounding indication signal.

[0086] It should be noted that the above is a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, once the basic creative concept of the present invention is known, a number of improvements and modifications can be made by a person skilled in the art without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A ground wire disconnection fault online detection system, characterized in that: include: an easy-oscillation circuit, electrically connected to the grounding point, for being in an oscillating state when the grounding point is disconnected from the ground, and being in a stable state when the grounding point is well connected to the ground; an oscillation detection circuit, electrically connected to the easy-oscillation circuit, and used to detect a circuit state of the easy-oscillation circuit; an indicating circuit, electrically connected to the oscillation detection circuit, and used for indicating a detection result of the oscillation detection circuit; The power supply switch power supply module is electrically connected to the easy-oscillation circuit, the oscillation detection circuit and the indication circuit, and is used to convert the input industrial frequency alternating current into direct current and supply power to the easy-oscillation circuit, the oscillation detection circuit and the indication circuit.

2. The ground wire disconnection fault online detection system according to claim 1, characterized in that: The easy-oscillation circuit comprises: A first resistor and a second resistor connected in series, wherein a first end of the first resistor is electrically connected to the positive electrode of the power supply switch power supply module; a second end of the first resistor is electrically connected to a first end of the second resistor, and a second end of the second resistor is electrically connected to the grounding point; A flying lead, a first end of which is electrically connected to the positive electrode of the power supply module of the power supply switch; A third resistor and a fourth resistor connected in series, wherein a first end of the third resistor is electrically connected to a second end of the flying lead, a second end of the third resistor is electrically connected to a first end of the fourth resistor, and a second end of the fourth resistor is electrically connected to a negative electrode of the power supply switch power supply module; The comparison amplifier element is an operational amplifier or a comparator, whose non-inverting input terminal is electrically connected to the second end of the first resistor, whose inverting input terminal is electrically connected to the second end of the third resistor, and whose output terminal outputs a signal S1; whose positive and negative power supply terminals are electrically connected to the positive and negative electrodes of the power supply switch power supply module respectively; a fifth resistor and a sixth resistor connected in series, wherein a first end of the fifth resistor is electrically connected to the output end of the operational amplifier, a second end of the fifth resistor is electrically connected to a first end of the sixth resistor, and a second end of the sixth resistor is connected to a negative electrode of the power supply switch power supply module; and a second end of the fifth resistor outputs a signal S2; The first resistor and the second resistor are low-value resistors, and their resistance values ​​are both less than 10 kΩ. The third resistor and the fourth resistor are high-value resistors, and their resistance values ​​are both greater than 1 GΩ.

3. The grounding wire disconnection fault online detection system according to claim 2, characterized in that: The oscillation detection circuit detects the circuit state of the easy-to-oscillate circuit by detecting the count value per unit time of the AC signal in the easy-to-oscillate circuit. The oscillation detection circuit includes a digital processor for receiving the signal S2 from the easy-to-oscillate circuit and outputting an oscillation detection result output signal S3.

4. The ground wire disconnection fault online detection system according to claim 2, characterized in that: The oscillation detection circuit detects the circuit state of the easy-to-oscillate circuit by detecting the AC signal component in the easy-to-oscillate circuit. The oscillation detection circuit includes: A first capacitor, a first end of which is used to receive the signal S2; A first diode, an anode of which is electrically connected to the second end of the first capacitor; and a cathode of which outputs an oscillation detection result output signal S3; a second diode, a cathode of which is electrically connected to the second end of the first capacitor, and an anode of which is electrically connected to the negative electrode of the power supply switch power supply module; The filtering circuit includes a second capacitor and a seventh resistor, wherein the first ends of the second capacitor and the seventh resistor are electrically connected to the cathode of the first diode, and the second ends of the second capacitor and the seventh resistor are electrically connected and electrically connected to the negative electrode of the power supply switch power supply module.

5. The ground wire disconnection fault online detection system according to claim 2, characterized in that: The indicating circuit comprises: A signal driving circuit, whose input end is used to receive the oscillation detection result output signal S3; The sound and light indication circuit has an input end electrically connected to the output end of the signal driving circuit and is used to send out an alarm signal according to the driving signal; the sound and light indication circuit can be a buzzer or a light emitting diode.

6. A detection method based on the ground wire disconnection fault online detection system according to any one of claims 1 to 5, characterized in that: The specific steps include: Step S1, the industrial frequency alternating current supplies power to the easy-oscillation circuit, the oscillation detection circuit and the indication circuit through the power supply switch power supply module; Step S2, detecting the state of the easy-to-oscillate circuit by means of the oscillation detection circuit; Step S3: If the grounding point is well grounded, the oscillation detection circuit detects that the easy-to-oscillate circuit is in a stable state, and the indication circuit generates a good grounding indication signal; if the grounding point is disconnected from the ground, the oscillation detection circuit detects that the easy-to-oscillate circuit is in an oscillating state, and the indication circuit generates a poor grounding indication signal.

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