CN110850177A - High-frequency pulse digital ground resistance tester - Google Patents
High-frequency pulse digital ground resistance tester Download PDFInfo
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- CN110850177A CN110850177A CN201911326755.XA CN201911326755A CN110850177A CN 110850177 A CN110850177 A CN 110850177A CN 201911326755 A CN201911326755 A CN 201911326755A CN 110850177 A CN110850177 A CN 110850177A
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- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
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Abstract
The invention discloses a high-frequency pulse digital ground resistance tester, which comprises: the device comprises a power supply, a high-frequency pulse generator, a tested ground resistance loop, an analog-to-digital conversion circuit, an MCU and a display; the power supply is used for supplying power to the tester; the high-frequency pulse generator is used for generating square waves with the frequency of 20KHz and the duty ratio of 50 percent and inputting the square waves into a tested grounding resistance loop; the analog-to-digital conversion circuit is used for converting the test voltage of the tested ground resistance loop into a digital signal and transmitting the digital signal to the MCU for processing; the MCU calculates the received digital signal, calculates the resistance value of the tested grounding resistor, simultaneously displays the square wave waveform of the tested grounding point in the display, and is also used for controlling the analog-digital conversion circuit; the tester can display the voltage waveform of a measured point through the display screen, and further judge the type of the grounding resistance of the measured point; the high-frequency pulse digital ground resistance tester adopts a rechargeable battery for power supply, reduces external interference, and is convenient for field operation, carrying and testing.
Description
Technical Field
The invention relates to the field of ground resistance testers, in particular to a high-frequency pulse digital ground resistance tester.
Background
In power systems, it is often necessary to connect certain parts of the power system and its electrical equipment to ground for operational and safety requirements. The earth contains conductive substances such as water in nature. It is also electrically conductive. When a live conductor is in contact with the ground, a hemispherical ground field centered on the ground point is formed. At this time, the grounding current flows into the ground from the grounding point through the conductor and is dispersed in a hemispherical shape around the conductor. Whether the grounding device is good or not is directly related to the safety of people and equipment, and even relates to the normal and stable operation of the system. The grounding can prevent the human body from being subjected to electric shock, equipment and lines from being damaged, prevent fire and lightning stroke, prevent electrostatic damage and ensure the normal operation of a power system.
For the operation of the power system, the neutral point of the transformer or the generator is often grounded directly or through a special device, and this grounding mode is called as an operation grounding. Its ground resistance should not exceed 10 omega. In order to prevent the danger of electric shock to human body caused by insulation damage of the electrical equipment, the metal shell of the electrical equipment is connected with the grounding body in a good metal manner, so that the protection grounding is called as safety grounding. Its ground resistance should not exceed 4 omega. The ground resistance value of the ground device in the yard is required to be as follows: the ground resistance of the emptying pipe and the lighthouse is less than 10 omega; the grounding resistance of the communication and automatic control equipment is less than 2 omega; the antistatic grounding resistance of the station yard is less than 10 omega; the grounding resistance of the transformer in the distribution room is less than 4 omega; and the grounding resistance is less than 1 omega when the joint grounding is carried out.
Whether the grounding device is good or not is directly related to the safety of people and equipment, and even relates to the normal and stable operation of the system. In actual use, various grounding devices are periodically maintained and checked, and temporary inspection and maintenance are performed according to actual conditions at ordinary times. The period of maintenance inspection of the earthing device is generally: for grounding grids of power transformation and distribution substations or grounding devices of factory workshops, the grounding resistance value is measured once every year to see whether the grounding resistance value meets the requirements or not, and the change of the grounding resistance value is analyzed by comparing with the last measured value. For other earthing devices, measurements are required every two years. The grounding device is subjected to 1-2 times of comprehensive maintenance and inspection every year according to factors such as the scale of the grounding device, seasonal changes of importance in an electrical system and the like.
The existing common ground resistance tester, a shaking table type or a digital type, adopts high-low voltage low-frequency alternating current, high-low voltage high-frequency alternating current, high-low voltage variable frequency alternating current, high-low voltage direct current and the like to flow through a tested body to test the ground resistance value and the impedance, adopts alternating current or direct current, has single frequency, and gradually changes along the rising edge and the falling edge, and cannot well reflect whether the ground impedance is inductive impedance, capacitive impedance or pure resistance impedance.
Disclosure of Invention
The invention provides a high-frequency pulse digital ground resistance tester, and aims to solve the technical problems in the prior art.
The invention adopts low-voltage high-frequency pulse voltage as a test power supply, namely 20KHz square wave voltage with 50% duty ratio, inputs a tested grounding point, the 20KHz square wave current flows back to a tester through a remote ground loop, the grounding resistance of the tested grounding point is calculated by an MCU (microprogrammed control Unit) through testing three-point square wave peak voltage, meanwhile, the voltage waveform of a tested point is displayed through an LCD (liquid crystal display) screen, and the grounding resistance of the tested point is judged to belong to capacitive, inductive or pure resistive through the change of the rising edge and the falling edge of the square wave; and observing the change conditions of the rising edge and the falling edge of the square wave, and roughly judging the size of the stray inductance or the stray capacitance.
The high-frequency pulse digital ground resistance tester adopts a rechargeable battery for power supply, reduces external interference, is convenient for field operation and is convenient to carry.
The high-frequency pulse digital ground resistance tester adopts high-frequency pulses, can not disconnect the ground wire under the condition that adjacent ground points are far away, utilizes the characteristic that line inductance is large to high-frequency impedance, and the far ground point is small in high-frequency pulse current shunt, neglects errors and can directly test the ground resistance to be tested.
In order to achieve the above object, the present invention provides a high-frequency pulse digital ground resistance tester, comprising:
the device comprises a power supply, a high-frequency pulse generator, a tested ground resistance loop, an analog-to-digital conversion circuit, an MCU and a display; the power supply is used for supplying power to the tester; the high-frequency pulse generator is used for generating square waves with the frequency of 20KHz and the duty ratio of 50 percent and inputting the square waves into a tested grounding resistance loop; the analog-to-digital conversion circuit is used for converting the test voltage of the tested ground resistance loop into a digital signal and transmitting the digital signal to the MCU for processing; the MCU calculates the received digital signal, calculates the resistance value of the tested grounding resistor, simultaneously displays the square wave waveform of the tested grounding point in the display, and is also used for controlling the analog-digital conversion circuit.
Preferably, the power supply comprises: lithium cell, charging circuit and electric quantity display module, lithium cell are used for providing DC voltage for the tester, and charging circuit charges for the lithium cell, and electric quantity display module is used for showing the residual capacity of lithium cell.
Preferably, the power supply comprises: transformer T, rectifier module D, filter module C, lithium cell charge and discharge control module, the lithium cell, switch K and battery circuit monitoring display module, transformer T high-voltage side is connected with power AC220V, transformer low-voltage side is connected with rectifier module D, rectifier module D is connected with filter module C, filter module C is connected with lithium cell charge and discharge control module, lithium cell charge and discharge control module is connected with the lithium cell, the lithium cell positive pole is connected with switch K one end, the switch K other end is connected with battery circuit monitoring display module and power positive pole, the lithium cell negative pole is connected with battery circuit monitoring display module and power negative pole.
Preferably, the square wave peak voltage V1, the square wave peak voltage V2 and the perigee square wave peak voltage V3 in the tested grounding resistance loop are all input into the analog-digital conversion circuit.
Preferably, the high frequency pulse generator includes: the current input ends of the first IC, the second IC, the third IC, the resistor R1, the resistor RT, the resistor R2, the capacitor CT, the resistor R3, the field-effect tube Q1 and the field-effect tube Q2 are all connected with the positive pole of a power supply, the source electrode of the field-effect tube Q2 is connected with the 1 st pin of the first IC, the drain electrode of the field-effect tube Q2 is connected with the positive output end of a high-frequency pulse generator, one end of the resistor R1, the 8 th pin of the third IC and one end of the resistor R3 are all connected with the 6 th pin of the first IC, the other end of the resistor R3 and the gate electrode of the field-effect tube Q2 are all connected with the collector electrode of the field-effect tube Q1, the other end of the resistor R1 and one end of the resistor RT are all connected with the 7 th pin of the third IC, the 2 nd pin of the third IC and the other end of the resistor RT are all connected with the positive pole of the capacitor CT, the negative pole of the capacitor CT, the pins of the 2 and the positive and negative pole of the field-effect tube Q, one end of the resistor R2 is connected with the 3 rd pin of the third IC, and the other end of the resistor R2 is connected with the base electrode of the field effect transistor Q1.
Preferably, the ground resistance circuit to be tested includes:
a resistor R4, a resistor R5 and a resistor R6; one end of a resistor R4 is connected with the positive output end of the high-frequency pulse generator, the other end of a resistor R4 is connected with one end of a resistor R6 and one end of a resistor R5, the other end of the resistor R6 is connected with the test point, the other end of a resistor R5 is connected with the negative output end of the high-frequency pulse generator and the far-ground point, one end of a ground resistor RX is connected with the test point, and the other end of the ground resistor RX is connected with the near-ground point and the far-ground point.
Preferably, V1, V2 and V3 are input to an analog-to-digital conversion circuit, the analog-to-digital conversion circuit outputs a/D status and binary digital stream to the MCU, and the MCU outputs clock signals and control signals to the analog-to-digital conversion circuit.
Preferably, binary digits of V1, V2 and V3 after A/D conversion are sent to the MCU, the resistance RX of the tested ground resistor is obtained through the MCU operation, and the calculation formula is as follows:
wherein, RX is the grounding resistance, and I is the test current.
Preferably, the type of the grounding resistance can be judged by the waveform of the square wave peak voltage V2 of the tested grounding point.
Preferably, the types of the ground resistance include: pure resistive ground resistors, capacitive ground resistors, inductive ground resistors, and mixed capacitive and inductive ground resistors.
One or more technical schemes provided by the invention at least have the following technical effects or advantages:
the high-frequency pulse digital ground resistance tester adopts 20KHz square waves with 50% duty ratio as a test power supply, and under the condition that adjacent sites are far away, the ground resistance tester can directly test the ground resistance of a ground wire without untying an electrical ground connection point by utilizing the characteristics of large resistance of line inductance to high-frequency inductance and small shunt of high-frequency pulses and neglecting small errors by utilizing the characteristics of line inductance to high-frequency inductance and small shunt of high-frequency pulses.
The high-frequency square wave current generates high-frequency square wave voltage on the grounding resistor in a loop flowing through the grounding resistor to be detected, and the sizes of the stray inductance and the stray capacitance of the grounding point can be determined by observing the change of the rising edge and the falling edge of the square wave: if the rising edge and the falling edge of the square wave are steep, the stray inductance and the stray capacitance of the grounding point are very small or even none, and the grounding resistance is close to or equal to the pure resistance; if the rising edge of the square wave is changed slowly, the size of the stray inductance is determined slightly through the gradual change of the rising edge, and the stray inductance has a delay effect on high-frequency overshoot voltage, particularly lightning discharge, of the ground resistance with inductive reactance and is harmful to electricity needing ground protection; if the falling edge of the square wave is changed slowly, the fact that the stray capacitance exists when the grounding point grounding wire enters the ground is shown, the size of the stray capacitance can be determined slightly through the gradual change size of the falling edge, and the effect of delaying the discharge of low-frequency overshoot voltage on grounding resistance with capacitive reactance is achieved.
A high-frequency pulse digital ground resistance tester adopts a near-ground and far-ground testing mode, wherein the near-ground is 20 meters and the far-ground is 40 meters, the conductive condition of the ground around a grounding wire entering point of 40 meters and the ground can be measured, if the conductive performance of the ground is poor, the ground resistance of a tested point is large, and the conductive performance of the ground is different along with the change of climate and humidity.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention;
FIG. 1 is a schematic diagram of the high frequency pulse digital ground resistance tester of the present application;
FIG. 2 is a schematic diagram of the power supply components of the present application;
FIG. 3 is a schematic diagram of the high frequency pulse generator composition of the present application;
FIG. 4 is a schematic diagram of a high frequency pulse output test in the present application;
FIG. 5 is a schematic diagram of the A/D connection of the present application;
FIG. 6 is a schematic diagram of MCU connection in the present application;
fig. 7 is a schematic diagram of the types of ground resistors corresponding to different waveforms in the present application.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflicting with each other.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described and thus the scope of the present invention is not limited by the specific embodiments disclosed below.
It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced devices or components must be constructed and operated in a particular orientation and thus are not to be considered limiting.
It is understood that the terms "a" and "an" should be interpreted as meaning that a number of one element or element is one in one embodiment, while a number of other elements is one in another embodiment, and the terms "a" and "an" should not be interpreted as limiting the number.
Referring to fig. 1, an embodiment of the present invention provides a high-frequency pulse digital ground resistance tester, including:
(1) and a power supply: the system consists of a lithium battery, a charging circuit and an electric quantity display, and provides stable direct-current voltage for the system.
(2) And a high-frequency pulse generator: a square wave of 20KHz with a 50% duty cycle is generated.
(3) And high-frequency pulse output test: the high-frequency pulse square wave is output to a tested point through an output circuit, high-frequency pulse current flows into a system through a grounding wire and a system far-ground loop, square wave peak voltage V1, tested ground point square wave peak voltage V2 and near point square wave peak voltage V3 output by the system flow in the high-frequency pulse current loop are tested, and three test voltages V1, V2 and V3 are sent to an A/D (analog/digital) circuit.
(4) And A/D: and the analog-to-digital conversion circuit performs analog-to-digital conversion on the input square wave peak voltages V1, V2 and V3, the resolution is 24bit, and the sampling rate is 1 Msps.
(5) And MCU: and the micro-control processor calculates digital signals of square wave peak voltages V1, V2 and V3, calculates the resistance value of the tested grounding resistor, and simultaneously displays the square wave waveform of V2 back on the LCD screen. And controlling the A/D acquisition circuit and completing man-machine conversation.
(6) And LCD display: the resistance value of the grounding resistor of the tested grounding point is displayed, and the square wave waveform of the V2 point is displayed.
Referring to fig. 2, fig. 2 is a schematic diagram of a power supply, wherein 220V ac is stepped down by a transformer T, rectified by a transformer D, and filtered by a transformer C, and outputs about 15V dc power for a lithium battery charge and discharge control module. And turning on a power switch K, starting the battery power monitoring and displaying module to work, displaying the residual power of the lithium battery, and simultaneously providing a 8-12V direct-current power supply for the system.
Referring to fig. 3, fig. 3 is a schematic diagram of the high frequency pulse generator; the 8-12V direct current is input, the voltage is stabilized by the IC LM7805, the +5V voltage is output to the IC NE555 to generate square waves with 20KHz and 50 percent duty ratio, and the RT and the CT are adjusted to stabilize the frequency of the output square waves at 20 KHz. The square wave signal output by IC NE555 drives Q2 through Q1. The IC MC34063 DC/DC converts the input 8-12V voltage into +28V direct current voltage, and the direct current voltage is chopped into square wave voltage with 20KHz, 50 percent duty ratio and 28V peak-to-peak value by Q2.
Referring to fig. 4, fig. 4 is a schematic diagram of a high frequency pulse output test, wherein a 20KHz square wave voltage with a 50% duty ratio having a peak-to-peak value of 28V is input, flows through a parallel circuit of R4, R5 and R6 RX, and returns to the negative electrode of the system. R4, R5 and R6 are fixed resistors in the high-frequency pulse digital ground resistance tester system, RX is the ground resistance of the tested ground point, and the broken line is a loop formed by the ground. R6 is a precision non-inductive resistor. V1, V2 and V3 are peak voltages of the square wave voltage waveform of the measured point. V1 flows through R6, the ground point to be tested is connected to the ground line, and the earth (dotted line) loop flows back to the negative pole of the system.
Referring to fig. 5, fig. 5 is a schematic diagram of a/D input and output connections, wherein V1, V2, and V3 are sent to IC LTCs 2368-24A/D to perform a/D conversion on V1, V2, and V3 to form binary digits with a resolution of 24 bits, and the converted digital signals are sent to the MCU under the control of the MCU. The IC LTCs 2368-24A/D are 24bit resolution, 1Msps sampling rate.
Referring to fig. 6, fig. 6 is a schematic diagram of MCU connection, wherein binary digits of V1, V2, and V3 after a/D conversion are sent to ICSTC8A4K32S2 MCU, and calculated by MCU software to obtain the resistance RX of the ground resistor under test, the formula is:
wherein, RX is the grounding resistance, and I is the test current.
The man-machine interface sends the required control names, such as: and testing and clearing the command.
When V1-V2 is 0, it indicates that no current flows through the ground path, and the ground point to be tested may be disconnected from the ground line, or the remote ground drill may not be well drilled. The output line and the remote access line of the high-frequency pulse digital tester are respectively connected to two ends of a hinge point of the grounding wire, so that whether the hinge point is in good contact or not can be detected, and if V2-V3 is 0, the contact is good.
Referring to fig. 7, fig. 7 is a schematic diagram of grounding resistance types corresponding to different waveforms, where the LCD display screen is a liquid crystal dot matrix screen, and displays a tested grounding resistance value and a waveform of V2. The magnitude of the stray inductance and the stray capacitance can be determined by displaying the waveform of V2.
The pure-resistance grounding resistor is optimal and has steep rising edge and steep falling edge, which shows that the grounding resistor has good response to high frequency and quick response to the discharge of high and low frequency overvoltage.
The technical scheme of the invention has the following characteristics:
1. the high-frequency pulse digital ground resistance tester adopts a high-frequency pulse wave power supply as a ground resistance testing power supply, and the high-resolution A/D of the peak value of pulse waves can achieve the testing level precision of 0.1 ohm. The size of the near-ground and far-ground drill rod access resistance does not influence the test calculation of the ground resistance of the tested point.
2. The high-frequency pulse digital ground resistance tester adopts a square wave with 20KHz high-frequency pulse and 50% duty ratio as a test power supply, square wave current flows through the ground resistance of a tested point, the generated square wave voltage waveform is displayed on an LCD screen, and the change condition of the rising edge and the falling edge of the square wave is observed. The sizes of stray inductance and stray capacitance of a grounding wire of a tested point and the earth can be estimated approximately, the leakage of high-frequency and low-frequency overvoltage can be influenced by the sizes of the stray inductance and the stray capacitance, and the effect of grounding protection is reduced.
3. The high-frequency pulse digital ground resistance tester adopts an access test method of 20 meters near the ground and 40 meters far from the ground, can measure the conductivity of 40 meters of ground around a tested point, the conductivity of the ground greatly changes with the difference of climate and humidity, the conductivity of the ground around the tested ground point is low, and the ground resistance is increased and even exceeds the standard requirement.
4. The high-frequency pulse digital grounding resistance tester adopts a high-frequency pulse power supply, and if a tested grounding point is far away from an adjacent grounding point, because the impedance of a line inductor to high frequency is large, the flowing high-frequency pulse current is small, and under the condition of neglecting errors, the testing can be directly carried out without unlinking the link between the tested point grounding line and electrical equipment.
5. The high-frequency pulse digital grounding resistance tester connects the output line and the far ground wire to two sides of the hinge point of the grounding wire respectively, and can measure whether the hinge point has contact resistance or broken circuit.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A high frequency pulse digital ground resistance tester, the tester comprising:
the device comprises a power supply, a high-frequency pulse generator, a tested ground resistance loop, an analog-to-digital conversion circuit, an MCU and a display; the power supply is used for supplying power to the tester; the high-frequency pulse generator is used for generating square waves with the frequency of 20KHz and the duty ratio of 50 percent and inputting the square waves into a tested grounding resistance loop; the analog-to-digital conversion circuit is used for converting the test voltage of the tested ground resistance loop into a digital signal and transmitting the digital signal to the MCU for processing; the MCU calculates the received digital signal, calculates the resistance value of the tested grounding resistor, simultaneously displays the square wave waveform of the tested grounding point in the display, and is also used for controlling the analog-digital conversion circuit.
2. The high frequency pulsed digital ground resistance tester of claim 1, wherein the power supply comprises: lithium cell, charging circuit and electric quantity display module, lithium cell are used for providing DC voltage for the tester, and charging circuit charges for the lithium cell, and electric quantity display module is used for showing the residual capacity of lithium cell.
3. The high frequency pulsed digital ground resistance tester of claim 1, wherein the power supply comprises: transformer T, rectifier module D, filter module C, lithium cell charge and discharge control module, the lithium cell, switch K and battery circuit monitoring display module, transformer T high-voltage side is connected with power AC220V, transformer low-voltage side is connected with rectifier module D, rectifier module D is connected with filter module C, filter module C is connected with lithium cell charge and discharge control module, lithium cell charge and discharge control module is connected with the lithium cell, the lithium cell positive pole is connected with switch K one end, the switch K other end is connected with battery circuit monitoring display module and power positive pole, the lithium cell negative pole is connected with battery circuit monitoring display module and power negative pole.
4. The high-frequency pulse digital ground resistance tester as claimed in claim 1, wherein the square wave peak voltage V1, the square wave peak voltage V2 of the ground point to be tested and the square wave peak voltage V3 of the perigee in the ground resistance circuit to be tested are all inputted into the analog-to-digital conversion circuit.
5. The high-frequency pulse digital ground resistance tester according to claim 1, wherein the high-frequency pulse generator comprises: the current input ends of the first IC, the second IC, the third IC, the resistor R1, the resistor RT, the resistor R2, the capacitor CT, the resistor R3, the field-effect tube Q1 and the field-effect tube Q2 are all connected with the positive pole of a power supply, the source electrode of the field-effect tube Q2 is connected with the 1 st pin of the first IC, the drain electrode of the field-effect tube Q2 is connected with the positive output end of a high-frequency pulse generator, one end of the resistor R1, the 8 th pin of the third IC and one end of the resistor R3 are all connected with the 6 th pin of the first IC, the other end of the resistor R3 and the gate electrode of the field-effect tube Q2 are all connected with the collector electrode of the field-effect tube Q1, the other end of the resistor R1 and one end of the resistor RT are all connected with the 7 th pin of the third IC, the 2 nd pin of the third IC and the other end of the resistor RT are all connected with the positive pole of the capacitor CT, the negative pole of the capacitor CT, the pins of the 2 and the positive and negative pole of the field-effect tube Q, one end of the resistor R2 is connected with the 3 rd pin of the third IC, and the other end of the resistor R2 is connected with the base electrode of the field effect transistor Q1.
6. The high frequency pulse digital ground resistance tester according to claim 1, wherein the ground resistance circuit under test comprises:
a resistor R4, a resistor R5 and a resistor R6; one end of a resistor R4 is connected with the positive output end of the high-frequency pulse generator, the other end of a resistor R4 is connected with one end of a resistor R6 and one end of a resistor R5, the other end of the resistor R6 is connected with the test point, the other end of a resistor R5 is connected with the negative output end of the high-frequency pulse generator and the far-ground point, one end of a ground resistor RX is connected with the test point, and the other end of the ground resistor RX is connected with the near-ground point and the far-ground point.
7. The high frequency pulse digital ground resistance tester according to claim 4, wherein V1, V2 and V3 are inputted into an analog-to-digital conversion circuit, the analog-to-digital conversion circuit outputs A/D status and binary digital stream to MCU, the MCU outputs clock signal and control signal to the analog-to-digital conversion circuit.
8. The high-frequency pulse digital ground resistance tester as claimed in claim 1, wherein the binary numbers of V1, V2 and V3 after a/D conversion are sent to the MCU, and the resistance RX of the ground resistance to be tested is obtained by the MCU calculation, and the calculation formula is:
wherein, RX is the grounding resistance, and I is the test current.
9. The high frequency pulse digital ground resistance tester according to claim 1, wherein the type of ground resistance can be judged by the waveform of the square wave peak voltage V2 of the ground point to be tested.
10. The high frequency pulsed digital ground resistance tester according to claim 9, characterized in that the types of ground resistance include: pure resistive ground resistors, capacitive ground resistors, inductive ground resistors, and mixed capacitive and inductive ground resistors.
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| CN201911326755.XA CN110850177A (en) | 2019-12-20 | 2019-12-20 | High-frequency pulse digital ground resistance tester |
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Cited By (3)
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