CN-115856439-B - Ground resistance measurement method

CN115856439BCN 115856439 BCN115856439 BCN 115856439BCN-115856439-B

Abstract

The invention provides a grounding resistance measuring device and a method thereof, wherein the grounding resistance measuring device comprises a grounding resistance measuring meter and two testing wires, the grounding resistance measuring meter is provided with an output electrode and an input electrode, one end of one of the two testing wires is connected with the output electrode, the other end of the other testing wire is connected with a grounding electrode inserted into the ground, one end of the other testing wire is connected with the input electrode, the other end of the other testing wire is connected with the measuring electrode inserted into the ground, a testing loop is formed, the grounding resistance measuring meter is used for measuring the resistivity within a unit distance, and the resistivity is used for calculating the grounding resistance value by combining the distance between the grounding electrode and the measuring electrode. The test of the invention is a two-point test method, and compared with a three-point or four-point test method, the length of the test line can be shortened, the weight of test equipment is reduced, and the test is convenient to detect and carry.

Inventors

ZHAO FAQIANG
LIN ZEBIN
MA JUNJUN
YU CHUNHUAN
LONG HAIBO
FU WEI
LUO HAO
LIU SONG
ZHONG LIANGYU
WU SHITONG

Assignees

深圳供电局有限公司

Dates

Publication Date: 20260512
Application Date: 20221202

Claims (3)

1. The ground resistance measuring device is characterized by comprising a ground resistance measuring meter and two test wires; The ground resistance measuring meter is provided with an output electrode and an input electrode, one end of one of the two test wires is connected with the output electrode, the other end of the one of the two test wires is connected with a ground electrode inserted into the ground, one end of the other of the two test wires is connected with the input electrode, and the other end of the other of the two test wires is connected with the measurement electrode inserted into the ground to form a test loop; The grounding resistance measuring meter comprises a storage battery, a constant voltage circuit, a switch circuit, a resistor, a control chip, a voltage sampling module and a display screen, wherein the storage battery is used for providing a working power supply, the constant voltage circuit is used for outputting voltage U, the control chip is used for controlling the switch circuit to be conducted or cut off the test loop, the voltage sampling module is used for sampling voltages at two ends of the resistor when the test loop is conducted, the control chip is also used for calculating the resistivity within a unit distance according to the voltage sampling result of the voltage sampling module, the display screen is used for displaying the resistivity, and the resistivity is used for calculating a grounding resistance value by combining the distance between two grounding poles; The control chip is specifically used for controlling the switching circuit to periodically turn on or off the test loop; The voltage sampling module is specifically configured to sample voltages at two ends of the output electrode and the input electrode for multiple times in each conduction period of the test loop to obtain voltage sampling results of multiple conduction periods, where the voltage sampling result of each conduction period includes multiple sampling voltage values; The control chip is further configured to calculate an average voltage value U L according to voltage sampling results of the voltage sampling module in a plurality of on periods, calculate I L according to I L =U Flat plate /R L and the average voltage value U L and the resistor R L , and obtain the resistivity R within a unit distance according to r=u-U Flat plate /I L .
2. A ground resistance measurement method, characterized in that it is implemented based on the ground resistance measurement device of claim 1, said method comprising the steps of: One end of one of the two test lines is connected with the output electrode, the other end of the one of the two test lines is connected with the grounding electrode inserted into the ground, one end of the other one of the two test lines is connected with the input electrode, and the other end of the other one of the two test lines is connected with the measuring electrode inserted into the ground to form a test loop; Starting the grounding resistance measuring meter to measure; calculating a grounding resistance value according to the resistivity R in a unit distance displayed by the grounding resistance measuring meter and combining the distance between two actual grounding poles; the calculating the grounding resistance value according to the resistivity R in the unit distance displayed by the grounding resistance measuring meter and combining the distance between the two actual grounding poles comprises the following steps: calculating the multiple of the unit distance and the distance between the grounding electrode and the measuring electrode; Multiplying the resistivity R per unit distance by the multiple gives the ground resistance.
3. The ground resistance measurement method according to claim 2, characterized in that the method further comprises: And taking the grounding electrode as a circle center, enabling the measuring electrode to circularly move around the circle center for a certain distance to one or more other positions, and continuously and repeatedly measuring to obtain one or more corresponding grounding resistivities.

Description

Ground resistance measurement method Technical Field The invention relates to the technical field of electric power, in particular to a ground resistance measurement method. Background The grounding is characterized in that a certain part of equipment is precisely connected with the ground through a grounding device, the grounding in a power network is one of the most widely applied electrical safety measures, different modes and different purposes of grounding measures are adopted for users of high and low voltage power grids, alternating current and direct current power transmission and distribution equipment, the grounding is mainly used for preventing personal electric shock, equipment and lines from being damaged, preventing fire and lightning stroke, preventing electrostatic damage and guaranteeing normal operation of a power system, wherein the grounding resistor is a resistor in which current flows into the ground from the grounding device and then flows to another grounding body through the ground or is spread to a distance, the grounding resistor reflects the contact degree of the electrical device and the ground and reflects the scale of the grounding network, and the grounding resistor is required to meet the standard requirements to play a role in protecting and preventing accidents. The grounding resistance tester adopted at present adopts two types of a megger and a digital type, a three-point wiring method is adopted for measuring the grounding resistance, 3 sections of testing wires which are 5 meters, 20 meters and 40 meters are needed for the current testing method, the resistance value is measured by a voltage adding mode, the grounding resistance is tested by the testing method, the lead wire is too long, time is needed for operation, and the long wire is inconvenient to carry. During the megger test, voltage is unstable, and output voltage is related with hand rotational speed, and measuring result is less accurate. Disclosure of Invention The invention aims to provide a grounding resistance measuring method, which aims to solve the technical problems of how to conveniently measure the grounding resistance and improve the accuracy of a measuring result. The invention provides a ground resistance measuring method, which comprises a ground resistance measuring meter and two test lines; The ground resistance measuring meter is provided with an output electrode and an input electrode, one end of one of the two test wires is connected with the output electrode, the other end of the one of the two test wires is connected with a ground electrode inserted into the ground, one end of the other of the two test wires is connected with the input electrode, and the other end of the other of the two test wires is connected with the measurement electrode inserted into the ground to form a test loop; The grounding resistance measuring meter comprises a storage battery, a constant voltage circuit, a switching circuit, a resistor, a control chip, a voltage sampling module and a display screen, wherein the storage battery is used for providing a working power supply, the constant voltage circuit is used for outputting voltage U, the control chip is used for controlling the switching circuit to be conducted or cut off the test loop, the voltage sampling module is used for sampling voltages at two ends of the resistor when the test loop is conducted, the control chip is further used for calculating and obtaining the resistivity in a unit distance according to the voltage sampling result of the voltage sampling module, the display screen is used for displaying the resistivity, and the resistivity is used for calculating a grounding resistance value by combining the distance between two actual grounding poles. Preferably, the control chip is specifically configured to control the switching circuit to periodically turn on or off the test loop; The voltage sampling module is specifically configured to sample voltages at two ends of the output electrode and the input electrode for multiple times in each conduction period of the test loop to obtain voltage sampling results of multiple conduction periods, where the voltage sampling result of each conduction period includes multiple sampling voltage values; The control chip is further configured to calculate an average voltage value U L according to voltage sampling results of the voltage sampling module in a plurality of on periods, calculate I L according to I L＝U Flat plate /RL and the average voltage value U L and the resistor R L, and obtain the resistivity R within a unit distance according to r=u-U Flat plate /IL. The invention also provides a ground resistance measuring method based on the ground resistance measuring device, which comprises the following steps: One end of one of the two test lines is connected with the output electrode, the other end of the one of the two test lines is connected with the grounding electrode inserted into the ground, one e