Grounding resistance detector and grounding resistance detection system

Abstract

The utility model discloses a ground resistance detector and a ground resistance detection system. The detector specifically comprises a control module; the detection electrode comprises a current electrode, a voltage electrode and a grounding electrode; the current electrode, the voltage electrode and the grounding electrode are all arranged in soil near the lead to be measured, and the voltage electrode is arranged between the current electrode and the grounding electrode; the grounding electrode is electrically connected with the to-be-tested lead; the constant-current module is used for generating constant-current voltage, the current electrode is used for guiding the constant-current voltage into soil near the lead to be measured, and the grounding electrode is used for receiving the constant-current voltage transmitted by the current electrode; the acquisition module is used for acquiring a first voltage signal generated when the constant-current voltage passes through the soil near the voltage electrode; the analog-to-digital conversion module is used for converting the first voltage signal from an analog signal to a digital signal; and the communication module is used for transmitting the first voltage signal to an upper computer. According to the grounding resistance detector provided by the utility model, real-time grounding resistance data can be remotely acquired at any position to be detected.

Description

Technical Field

[0001] The utility model relates to but is not limited to the field of grounding resistance detection, and in particular to a grounding resistance detector and a grounding resistance detection system. Background Art

[0002] The test of grounding resistance is an indispensable part of the completion acceptance of grounding projects and electrical safety inspections. The grounding resistance value is a key indicator to measure the effectiveness and safety of the grounding system, and it is also an important parameter to determine whether the grounding system meets the design standards. If there are defects in the grounding system, electrical equipment may be damaged by lightning strikes in minor cases, and may lose its protective function for personal safety in serious cases, posing a huge threat to national property and human life safety. Therefore, the accuracy of grounding resistance measurement has a direct impact on the lightning protection, working reliability and personal safety protection of electrical equipment. However, the existing grounding resistance test method mainly relies on maintenance personnel to use handheld maintenance equipment for on-site testing. This method can only obtain the grounding resistance data at the time of the test, resulting in data lag. It is impossible to obtain grounding resistance data in real time during non-maintenance periods in order to effectively prevent grounding faults. In view of this, it is particularly urgent to develop a device that can monitor grounding resistance data in real time. Utility Model Content

[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0004] The embodiment of the utility model provides a ground resistance detector, which can obtain ground resistance data within a measurement range in real time.

[0005] In a first aspect, an embodiment of the utility model provides a ground resistance detector, comprising:

[0006] Control module;

[0007] The detection electrode comprises a current electrode, a voltage electrode and a ground electrode; the current electrode, the voltage electrode and the ground electrode are all arranged in the soil near the lead to be tested, the voltage electrode is arranged between the current electrode and the ground electrode; the ground electrode is electrically connected to the lead to be tested;

[0008] A constant current module, wherein the input end of the constant current module is electrically connected to the control module, and the output end of the constant current module is electrically connected to the current electrode; the constant current module is used to generate a constant current voltage, the current electrode is used to introduce the constant current voltage into the soil near the lead to be tested, and the ground electrode is used to receive the constant current voltage transmitted by the current electrode;

[0009] A collection module, used for acquiring a first voltage signal generated when the constant current voltage passes through the soil near the voltage electrode; a first input end of the collection module is electrically connected to the voltage electrode, and a second input end of the collection module is electrically connected to the ground electrode;

[0010] An analog-to-digital conversion module, wherein the output end of the acquisition module is electrically connected to the input end of the analog-to-digital conversion module, and the output end of the analog-to-digital conversion module is electrically connected to the control module; the analog-to-digital conversion module is used to convert the first voltage signal from an analog signal to a digital signal;

[0011] A communication module is electrically connected to the control module; the communication module is used to transmit the first voltage signal to a host computer.

[0012] According to the grounding resistance detector of the first embodiment of the utility model, at least the following beneficial effects are achieved: the current electrode, the voltage electrode and the grounding electrode are arranged near the lead to be measured based on the principle of measuring the grounding resistance by the three-pole method, the constant current voltage output by the constant current module is collected by the voltage electrode after the constant current voltage passes through the soil near the voltage electrode, and the first voltage signal generated is transmitted to the host computer through the communication module, and since the first voltage signal is necessary data for obtaining the grounding resistance of the corresponding lead, it is only necessary to obtain the first voltage signal to obtain the corresponding grounding resistance value according to the first voltage signal. Therefore, according to the grounding resistance detector of the utility model, the first voltage signal can be obtained in real time at any position to be measured and uploaded to the host computer, so that maintenance personnel can remotely obtain the real-time grounding resistance data of the position to be measured.

[0013] In some embodiments of the utility model, the constant current module includes a first push-pull circuit, a second push-pull circuit and a transformer; the first push-pull circuit includes a first switch tube and a second switch tube with opposite conduction directions; the second push-pull circuit includes a third switch tube and a fourth switch tube with opposite conduction directions; the first push-pull circuit and the second push-pull circuit are used to generate a constant current voltage, the input ends of the first push-pull circuit and the second push-pull circuit are respectively electrically connected to the control module, and the output ends of the first push-pull circuit and the second push-pull circuit are respectively electrically connected to the input end of the transformer; the output end of the transformer is electrically connected to the current pole.

[0014] In some embodiments of the present utility model, the acquisition module includes a first amplifier and a second amplifier; the in-phase input terminal of the first amplifier is electrically connected to the voltage electrode and the ground electrode respectively, and the inverting input terminal of the first amplifier is electrically connected to the output terminal of the first amplifier; the output terminal of the first amplifier is also electrically connected to the in-phase input terminal of the second amplifier, the inverting input terminal of the second amplifier is electrically connected to the output terminal of the second amplifier, and the output terminal of the second amplifier is electrically connected to the control module.

[0015] In some embodiments of the utility model, a rectifier module is also arranged between the acquisition module and the analog-to-digital conversion module, and the rectifier module includes a first resistor, a rectifier unit and a third amplifier; the rectifier unit includes a bridge rectifier circuit formed by a combination of a fifth switch tube and a sixth switch tube; the first end of the first resistor is electrically connected to the output end of the second amplifier and the inverting input end of the third amplifier, and the in-phase input end of the third amplifier is grounded; the output end of the third amplifier is electrically connected to the input end of the rectifier circuit, respectively, and the output end of the rectifier circuit is electrically connected to the second end of the first resistor; the output end of the rectifier circuit is also electrically connected to the inverting input end of the third amplifier; the rectifier module is used to convert the first voltage signal from an AC signal into a DC signal.

[0016] In some embodiments of the utility model, a filtering module is further arranged between the acquisition module and the analog-to-digital conversion module, and the filtering module includes a fourth amplifier, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor; the inverting input terminal of the fourth amplifier is electrically connected to the second end of the first resistor, and the non-inverting input terminal of the fourth amplifier is grounded; the output terminal of the fourth amplifier is electrically connected to the first end of the second resistor, and the second end of the second resistor is electrically connected to the first end of the third resistor and the first end of the first capacitor respectively; the second end of the first capacitor is grounded, and the second end of the third resistor is electrically connected to the control module; the output terminal of the fourth amplifier is also electrically connected to the first end of the fourth resistor and the first end of the second capacitor respectively, and the second end of the fourth resistor and the second end of the second capacitor are both electrically connected to the inverting input terminal of the fourth amplifier; the filtering module is used to filter out clutter in the first voltage signal.

[0017] In some embodiments of the utility model, the ground resistance detector also includes a display module and a key module, and the display module and the key module are electrically connected to the control module respectively; the display module is used to display the numerical value of the first voltage signal, and the key module is used to adjust the display content of the display module.

[0018] In some embodiments of the utility model, the ground resistance detector also includes an alarm module, which includes a first optocoupler, a first relay, a fifth switch tube and an alarm; the input end of the first optocoupler is electrically connected to the control module, and the output end of the first optocoupler is electrically connected to the controlled end of the fifth switch tube; the input end of the fifth switch tube is electrically connected to the coil of the first relay, and the contacts at both ends of the first relay are electrically connected to the alarm; the alarm module is used to alarm the ground resistance.

[0019] In a second aspect, an embodiment of the utility model provides a ground resistance detection system, which includes a host computer and a plurality of ground resistance detectors according to the embodiments of the above aspects.

[0020] According to the grounding resistance detection system of the second aspect of the utility model, there are at least the following beneficial effects: the grounding resistance detection system is composed of multiple grounding resistance detectors and a host computer, and maintenance personnel can obtain grounding resistance data of multiple detection points in real time.

[0021] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by implementing the utility model. The purpose and other advantages of the utility model can be achieved and obtained through the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the technical solution of the utility model and constitute a part of the specification. Together with the embodiments of the utility model, they are used to explain the technical solution of the utility model and do not constitute a limitation on the technical solution of the utility model.

[0023] Figure 1 A module block diagram of a ground resistance detector provided by an embodiment of the utility model;

[0024] Figure 2 is a schematic diagram of the detection electrode position provided by another embodiment of the utility model;

[0025] Figure 3 is a schematic diagram of a control module provided by another embodiment of the utility model;

[0026] Figure 4 This is a schematic diagram of a constant current module provided by another embodiment of the utility model;

[0027] Figure 5 It is a schematic diagram of a collection module provided by another embodiment of the utility model;

[0028] Figure 6 is a schematic diagram of a rectifier module and a filter module provided by another embodiment of the utility model;

[0029] Figure 7 It is a schematic diagram of an alarm module provided by another embodiment of the utility model.

[0030] Reference numerals: first push-pull circuit 1 , second push-pull circuit 2 , rectification module 3 , filtering module 4 . DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] In the description of the utility model, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0034] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0035] It should be noted that the embodiments of the present application do not limit the improvement of any method, and the functions that can be implemented by the device or apparatus are only implemented based on the hardware architecture of the device or apparatus itself.

[0036] The concepts involved in the utility model are explained below:

[0037] RS485: is a serial communication standard that provides a high-speed, long-distance data transmission method. The RS485 communication protocol is based on differential signal transmission, which means that it uses two transmission lines to send data instead of a single line like RS232. This differential signal transmission method can provide higher anti-interference ability and longer transmission distance.

[0038] Push-pull circuit: It is a common electronic circuit design, often used in power management, signal amplification and other fields. In the push-pull circuit, two power transistors (MOSFET) are connected to the positive and negative poles of the power supply respectively to form a symmetrical output terminal. When the input signal is high, the MOSFET on the left is turned on and the MOSFET on the right is turned off; conversely, when the input signal is low, the MOSFET on the left is turned off and the MOSFET on the right is turned on. Through this control method, the push-pull circuit can generate a voltage output opposite to the input signal, and the output voltage is always maintained at a fixed value, that is, constant current voltage.

[0039] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings.

[0040] Reference Figure 1-2 , Figure 1 The module block diagram of the ground resistance detector provided by the embodiment of the utility model, the detector specifically includes the following components: a control module; detection electrodes, including a current electrode C, a voltage electrode P and a ground electrode E; the current electrode C, the voltage electrode P and the ground electrode E are all inserted into the soil near the lead to be tested, and the voltage electrode P is arranged between the current electrode C and the ground electrode E; the ground electrode E is electrically connected to the lead to be tested; a constant current module, the input end of the constant current module is electrically connected to the control module, and the output end of the constant current module is electrically connected to the current electrode C; the constant current module is used to generate a constant current voltage, the current electrode C is used to introduce the constant current voltage into the soil near the lead to be tested, and the ground electrode E is used to receive A constant current voltage transmitted by the current electrode C through the soil near the lead to be tested; an acquisition module, used to obtain a first voltage signal generated after the constant current voltage passes through the soil near the voltage electrode P; a first input end of the acquisition module is electrically connected to the voltage electrode P, and a second input end of the acquisition module is electrically connected to the ground electrode E; an analog-to-digital conversion module, an output end of the acquisition module is electrically connected to an input end of the analog-to-digital conversion module, and an output end of the analog-to-digital conversion module is electrically connected to the control module; the analog-to-digital conversion module is used to convert the first voltage signal from an analog signal to a digital signal; a communication module, electrically connected to the control module; the communication module is used to transmit the first voltage signal to the host computer.

[0041] It should be noted that if Figure 2As shown, the detection principle of the grounding resistance in the embodiment of the utility model is the three-pole method. The principle of the three-level method for collecting the grounding resistance is to generate a current I through a constant current source a, and the current I generates a voltage V through the earth and the grounding electrode E. This voltage V flows into the device through the sampling voltage P electrode for data sampling (at this time, there is a voltmeter b in the device to convert the electrical signal into a numerical value), so that the actual resistance value of the grounding resistance can be obtained according to Ohm's theorem Rx=V / I. Based on the detection principle of obtaining the grounding resistance by the three-pole method, the voltage electrode P needs to be set between the current electrode C and the grounding electrode E. When the grounding resistance detector provided by the utility model is actually used, it is only necessary to insert the three electrodes of the current electrode C, the voltage electrode P and the grounding electrode E into the soil near the lead to be measured, and the constant current module is controlled by the control module to generate a constant current voltage with a constant current value and a known value, and then the first voltage signal of the nearby soil is obtained by the voltage electrode P and the acquisition module to obtain the resistance value of the grounding resistance. Since the grounding electrode E is connected to the lead to be measured, the above-mentioned voltage value V will be affected by the grounding resistance value of the lead to be measured, and then the voltage V is associated with the grounding resistance of the lead to be measured. It is understandable that in this process, the detector only needs to transmit the acquired first voltage signal to the host computer, and does not need to be transmitted to the control module for data processing. The function of the control module is only to maintain the normal operation of the detector, that is, to control the constant current module to generate a constant current voltage and upload the first voltage signal to the host computer through the communication module. Furthermore, the control module can be a single-chip microcomputer or other chip that can maintain the operation of the detector; since the constant current voltage output by the constant current source is an analog signal, an analog-to-digital conversion module is required to convert the analog signal into a digital signal that can be recognized by the control module.

[0042] Reference Figure 4 In some embodiments of the utility model, the constant current module includes a first push-pull circuit 1, a second push-pull circuit 2 and a transformer T1; the first push-pull circuit 1 includes a first switch tube Q13 and a second switch tube Q14 with opposite conduction directions; the second push-pull circuit 2 includes a third switch tube Q10Q15 and a fourth switch tube Q11Q16 with opposite conduction directions; the first push-pull circuit 1 and the second push-pull circuit 2 are used to generate a constant current voltage, the input ends of the first push-pull circuit 1 and the second push-pull circuit 2 are respectively electrically connected to the control module, and the output ends of the first push-pull circuit 1 and the second push-pull circuit 2 are respectively electrically connected to the input end of the transformer T1; the output end of the transformer T1 is electrically connected to the current electrode C.

[0043] It should be noted that Figure 4 The input end PWM1 of the first push-pull circuit 1 is the first input end of the constant current module, and the input end PWM2 of the second push-pull circuit 2 is the second input end of the constant current module. The first push-pull circuit 1 and the second push-pull circuit 2 are respectively used as the upper and lower arms of the overall push-pull circuit formed by the constant current module, and PWM1 and PWM2 are respectively connected to Figure 3The 10th and 11th pins of the control module are electrically connected. In the embodiment of the utility model, the 10th and 11th pins of the control module send complementary signals of PWM frequency selection 1KHz and 50% duty cycle to the first push-pull circuit 1 and the second push-pull circuit 2, so that the first switch tube Q13 and the second switch tube Q14, the third switch tube Q15 and the fourth switch tube Q16 are alternately turned on to achieve a stable output of a constant current voltage. Specifically, when the first switch tube Q13 and the third switch tube Q15 are turned on, the second switch tube Q14 and the fourth switch tube Q16 are turned off, and vice versa. This working mode allows current to flow back and forth at both ends of the load, thereby generating an AC signal on the load; further, by adjusting the pulse signal generated by the control module, the on and off time of the transistor can be adjusted, thereby maintaining the constant output current. After the first push-pull circuit 1 and the second push-pull circuit 2 generate a constant current voltage, the parameters such as the size of the constant current voltage are adjusted by the isolation transformer T1 T1, and the parameters are transmitted to the current pole C after adjustment.

[0044] Reference Figure 5 In some embodiments of the utility model, the acquisition module includes a first amplifier U7.1 and a second amplifier U7.2; the non-inverting input terminal of the first amplifier U7.1 is electrically connected to the voltage pole P and the ground pole E respectively, and the inverting input terminal of the first amplifier U7.1 is electrically connected to the output terminal of the first amplifier U7.1; the output terminal U7.1 of the first amplifier is also electrically connected to the non-inverting input terminal of the second amplifier U7.2, the inverting input terminal of the second amplifier U7.2 is electrically connected to the output terminal of the second amplifier U7.2, and the output terminal of the second amplifier U7.2 is electrically connected to the control module.

[0045] It should be noted that if Figure 5 As shown, the current electrode C and the grounding electrode E can form a constant current voltage loop, and the voltage electrode P can collect the first voltage signal from the soil near the loop. The acquisition module is used to obtain the first voltage signal from the voltage electrode P and amplify the first voltage signal. The first voltage signal is amplified and processed by the first amplifier U7.1 and the second amplifier U7.2 in turn, and finally output from the capacitor C39. Through the cascade of the two-stage amplifier, the quality of the first voltage signal can be improved, the noise and interference in the original signal can be reduced, and the signal-to-noise ratio of the signal can be improved; and it plays a role of buffering and isolation, preventing signal reflection and interference, and ensuring the stability of signal transmission.

[0046] Reference Figure 6In some embodiments of the utility model, a rectifier module 3 is also arranged between the acquisition module and the control module, and the rectifier module 3 includes a first resistor R19, a rectifier unit and a third amplifier U10.2; the rectifier unit includes a bridge rectifier circuit formed by a fifth switch tube Q10 and a sixth switch tube Q11; the first end of the first resistor R19 is electrically connected to the output end of the second amplifier and the inverting input end of the third amplifier U10.2, and the non-inverting input end of the third amplifier U10.2 is grounded; the output end of the third amplifier U10.2 is electrically connected to the input end of the rectifier circuit respectively, and the output end of the rectifier circuit is electrically connected to the second end of the first resistor R19; the output end of the rectifier circuit is also electrically connected to the inverting input end of the third amplifier U10.2; the rectifier module 3 is used to convert the first voltage signal from an AC signal into a DC signal.

[0047] It should be noted that, since the generated constant current voltage is an AC signal, the first voltage signal is also an AC signal. Before converting the first voltage signal from an analog signal to a digital signal, the AC signal needs to be converted into a DC signal to facilitate the identification of the IO port of the control module. In the embodiment of the utility model, a bridge rectifier circuit formed by the combination of the fifth switch tube Q10 and the sixth switch tube Q11 is used to rectify the first voltage signal, and the inverting input terminal of the third amplifier U10.2 is used as the input terminal to convert the first voltage signal from an AC signal to a DC signal and output it to the subsequent circuit.

[0048] Reference Figure 6 In some embodiments of the utility model, a filter module 4 is further provided between the acquisition module and the control module, and the filter module 4 includes a fourth amplifier U10.1, a second resistor R59, a third resistor R60, a fourth resistor R54, a first capacitor C40 and a second capacitor C12; the inverting input terminal of the fourth amplifier U10.1 is electrically connected to the second end of the first resistor, and the non-inverting input terminal of the fourth amplifier U10.1 is grounded; the output terminal of the fourth amplifier U10.1 is electrically connected to the first end of the second resistor R59, and the second end of the second resistor R59 is electrically connected to the first end of the third resistor R60 and the first end of the first capacitor C40 respectively; the second end of the first capacitor C40 is grounded, and the second end of the third resistor R60 is electrically connected to the control module; the output terminal of the fourth amplifier U10.1 is also electrically connected to the first end of the fourth resistor R54 and the first end of the second capacitor C12 respectively, and the second end of the fourth resistor R54 and the second end of the second capacitor C12 are both electrically connected to the inverting input terminal of the fourth amplifier U10.1; the filter module 4 is used to filter out clutter in the first voltage signal.

[0049] It should be noted that the filter module 4 provided in the embodiment of the utility model can filter out the noise in the first voltage signal through the RC filter circuit formed by the second resistor R59 and the first capacitor C40 and the filter loop formed by the fourth amplifier U10.1, the fourth resistor R54 and the second capacitor C12, and sample the first voltage signal after rectification and filtering through the third resistor R60 and transmit it to the 25th pin of the control module.

[0050] Reference Figure 1 In some embodiments of the utility model, the ground resistance detector also includes a display module and a key module, and the display module and the key module are electrically connected to the control module respectively; the display module is used to display the value of the first voltage signal, and the key module is used to adjust the display content of the display module.

[0051] It should be noted that the display module is used to display the voltage value corresponding to the first voltage signal, as well as the operating parameters related to the detector, such as the power of the detector, etc. The display module can be directly set on the body of the ground resistance detector, or the corresponding display data can be transmitted through the communication module and displayed through the host computer. The key module is used to adjust the content displayed by the display module, such as adjusting the display interface to display the voltage value of the first voltage signal or the parameter model of the detector, etc. It can be on the body of the ground resistance detector, or the corresponding key control can be performed through the host computer.

[0052] Reference Figure 7 In some embodiments of the utility model, the ground resistance detector also includes an alarm module, which includes a first optocoupler U3, a first relay K1, a fifth switch tube Q12 and an alarm DZ4; the input end of the first optocoupler U3 is electrically connected to the control module, and the output end of the first optocoupler U3 is electrically connected to the controlled end of the fifth switch tube Q12; the input end of the fifth switch tube Q12 is electrically connected to the coil of the first relay K1, and the contacts at both ends of the first relay K1 are electrically connected to the alarm DZ4; the alarm module is used to issue an alarm for ground resistance.

[0053] It should be noted that the first optocoupler U3 of the alarm module is composed of a transmitter, a receiver and an isolation barrier. When the input signal voltage is added to the base of the first optocoupler U3 transmitter, the transmitter generates current and converts the electrical signal into an optical signal through the photodiode of the first optocoupler U3, which is then transmitted to the first optocoupler U3 and then converted back into an electrical signal. Due to the existence of the isolation barrier of the first optocoupler U3, the electrical signal at the output end is completely isolated from the input end, thereby realizing the transmission and isolation of the alarm control signal. The control module controls the on and off of the first relay K1 through the first optocoupler U3, and then controls the alarm DZ4. Furthermore, in one embodiment of the utility model, when the value of the first voltage signal obtained by the control module is lower than or higher than a preset threshold, a corresponding alarm will be issued.

[0054] In some embodiments of the present utility model, the embodiments of the present utility model further include a whole machine power supply module, and the whole machine power supply module is used to supply power to the ground resistance detector.

[0055] In a second aspect, an embodiment of the utility model provides a ground resistance detection system, the system comprising a host computer and a plurality of ground resistance detectors according to the embodiments of the above aspects.

[0056] It should be noted that the ground resistance detection system includes ground resistance detectors set at any number and any detection points and a host computer connected to the above-mentioned detectors. Maintenance personnel can obtain real-time ground resistance data of each detection point through the host computer, and can perform fault prevention work on the corresponding detection points based on the real-time ground resistance data.

[0057] A specific embodiment is given below.

[0058] Reference Figure 1 The ground resistance detector mainly includes a control module, a display module, a key module, a communication module, a whole machine power module, an acquisition module, a rectifier module 3, a filter module 4 and an alarm module. The whole machine power module provides a stable power supply for the whole machine, wherein the display module can display the measured ground resistance value, soil resistivity and ground voltage through the control module. The key module can be implemented as an input button, and the user can input a control signal to the key module through the input button to realize the customized monitoring of the ground resistance. The alarm module can respond when detecting the alarm signal, such as setting, resetting and resetting the basic data of the ground resistance detector. The communication module can use RS485 to enable the control module and the host computer to exchange data and control in real time. The host computer can remotely control the monitoring system to perform operations such as re-measurement and data setting by analyzing the uploaded data or status information. The acquisition module mainly realizes the acquisition of the first voltage signal by combining the external current electrode C, the voltage electrode P and the ground electrode E. The host computer can obtain the measurement of relevant data such as ground resistance data, soil resistivity data and ground voltage data according to the first voltage signal. Before the acquisition module uploads the first voltage signal to the control module, the acquisition module needs to process the first voltage signal through the rectification module 3 and the filtering module 4 so that the control module can recognize it.

[0059] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A ground resistance detector, characterized in that: include: Control module; Detection electrodes, including a current electrode, a voltage electrode and a ground electrode; The current electrode, the voltage electrode and the ground electrode are all arranged in the soil near the lead to be tested, the voltage electrode is arranged between the current electrode and the ground electrode; the ground electrode is electrically connected to the lead to be tested; A constant current module, wherein an input end of the constant current module is electrically connected to the control module, and an output end of the constant current module is electrically connected to the current electrode; The constant current module is used to generate a constant current voltage, the current electrode is used to introduce the constant current voltage into the soil near the lead to be tested, and the ground electrode is used to receive the constant current voltage transmitted by the current electrode; An acquisition module, used for acquiring a first voltage signal generated when the constant current voltage passes through the soil near the voltage pole; The first input terminal of the acquisition module is electrically connected to the voltage electrode, and the second input terminal of the acquisition module is electrically connected to the ground electrode; An analog-to-digital conversion module, wherein the output end of the acquisition module is electrically connected to the input end of the analog-to-digital conversion module, and the output end of the analog-to-digital conversion module is electrically connected to the control module; the analog-to-digital conversion module is used to convert the first voltage signal from an analog signal to a digital signal; A communication module is electrically connected to the control module; the communication module is used to transmit the first voltage signal to a host computer.

2. The ground resistance detector according to claim 1, characterized in that: The constant current module includes a first push-pull circuit, a second push-pull circuit and a transformer; the first push-pull circuit includes a first switch tube and a second switch tube with opposite conduction directions; the second push-pull circuit includes a third switch tube and a fourth switch tube with opposite conduction directions; the first push-pull circuit and the second push-pull circuit are used to generate a constant current voltage, the input ends of the first push-pull circuit and the second push-pull circuit are respectively electrically connected to the control module, and the output ends of the first push-pull circuit and the second push-pull circuit are respectively electrically connected to the input end of the transformer; the output end of the transformer is electrically connected to the current electrode.

3. The ground resistance detector according to claim 1, characterized in that: The acquisition module includes a first amplifier and a second amplifier; the in-phase input terminal of the first amplifier is electrically connected to the voltage electrode and the ground electrode respectively, and the inverting input terminal of the first amplifier is electrically connected to the output terminal of the first amplifier; the output terminal of the first amplifier is also electrically connected to the in-phase input terminal of the second amplifier, the inverting input terminal of the second amplifier is electrically connected to the output terminal of the second amplifier, and the output terminal of the second amplifier is electrically connected to the control module.

4. The ground resistance detector according to claim 3, characterized in that: A rectifier module is also arranged between the acquisition module and the analog-to-digital conversion module, and the rectifier module includes a first resistor, a rectifier unit and a third amplifier; the rectifier unit includes a bridge rectifier circuit formed by a fifth switch tube and a sixth switch tube; the first end of the first resistor is electrically connected to the output end of the second amplifier and the inverting input end of the third amplifier, and the non-inverting input end of the third amplifier is grounded; the output end of the third amplifier is electrically connected to the input end of the rectifier circuit, respectively, and the output end of the rectifier circuit is electrically connected to the second end of the first resistor; the output end of the rectifier circuit is also electrically connected to the inverting input end of the third amplifier; the rectifier module is used to convert the first voltage signal from an AC signal into a DC signal.

5. The ground resistance detector according to claim 4, characterized in that: A filtering module is also arranged between the acquisition module and the analog-to-digital conversion module, and the filtering module includes a fourth amplifier, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor; the inverting input terminal of the fourth amplifier is electrically connected to the second end of the first resistor, and the non-inverting input terminal of the fourth amplifier is grounded; the output terminal of the fourth amplifier is electrically connected to the first end of the second resistor, and the second end of the second resistor is electrically connected to the first end of the third resistor and the first end of the first capacitor respectively; the second end of the first capacitor is grounded, and the second end of the third resistor is electrically connected to the control module; the output terminal of the fourth amplifier is also electrically connected to the first end of the fourth resistor and the first end of the second capacitor respectively, and the second end of the fourth resistor and the second end of the second capacitor are both electrically connected to the inverting input terminal of the fourth amplifier; the filtering module is used to filter out clutter in the first voltage signal.

6. The ground resistance detector according to claim 1, characterized in that: The ground resistance detector also includes a display module and a key module, and the display module and the key module are electrically connected to the control module respectively; the display module is used to display the value of the first voltage signal, and the key module is used to adjust the display content of the display module.

7. The ground resistance detector according to claim 1, characterized in that: The ground resistance detector also includes an alarm module, which includes a first optocoupler, a first relay, a fifth switch tube and an alarm; the input end of the first optocoupler is electrically connected to the control module, and the output end of the first optocoupler is electrically connected to the controlled end of the fifth switch tube; the input end of the fifth switch tube is electrically connected to the coil of the first relay, and the contacts at both ends of the first relay are electrically connected to the alarm; the alarm module is used to issue an alarm for ground resistance.

8. A ground resistance detection system, characterized in that: The system comprises a host computer and a plurality of ground resistance detectors as described in any one of claims 1-7.

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