5A Ground Resistance Tester

Ground resistance tester solves the anti-interference problem in the test process well, and also simplifying the test operation process, improving the accuracy and accuracy of the test results, and greatly reduces the labor intensity and test cost of the test personnel.

Ground resistance tester is a special instrument to measure the grounding conduction between the grounding resistance and the grounding point. By using frequency conversion and anti-interference technology, the instrument can measure 50 Hz of accurate data in the strong interference environment of substation without high current measurement. The measurement results are displayed by large screen liquid crystal and can be printed and output by micro printer. The instrument can measure the grounding impedance and the grounding resistance at the same time, and can reflect the actual characteristics of the ground grid more truthfully

Hot tags: Ground Network Earth Resistance Tester.

Grounding resistance tester, earth resistance tester,digital earth tester,earth resistance meter

1. The power frequency equivalence of the measurement is good. Test current waveform is sine wave, frequency and power frequency difference of 0.1 Hz, maximum of 10 Hz. which can be used to measure hz 50 or 60 frequencies.

2.Strong anti-interference ability. The instrument is measured by different frequency method, combined with modern software and hardware filtering technology, which makes the instrument have high anti-interference performance and stable and reliable test data.

3.High measurement accuracy. Basic error is only 0.005Ω, which can be used to measure earth grids with very small grounding impedance.

4. Powerful. Measurable current pile, voltage pile, grid impedance, grounding resistance, grounding conduction, soil resistivity, etc

5.Full touch LCD screen, super full graphical interface, each process is very clear. Operators do not need additional professional training to use. You can test the whole process with a touch

6.Equipped with calendar chips and large capacity memory, the results can be saved at any time. You can view history at any time and print output. Current time and storage time can be displayed and printed.

7. Scientific and advanced data management: instrument data can be exported through U disk, can be viewed and managed on any PC machine through special software. Ability to generate reports and test reports

8.Safe and reliable. The instrument has the functions of grounding protection, current limiting and voltage limiting protection, acousto-optic alarm and so on to ensure the safety of test personnel and equipment

9.With vector testing function, can measure the grid impedance and net pure resistance. The impedance angle can be measured

10.Wiring is small, no need for high current

11.Integrated model, with standard resistance and constant current source, easy to field test, reduce field wiring

12.The instrument is easy to operate, and the measurement process is controlled by the microprocessor. As long as the appropriate measurement mode is selected, the data measurement can be completed automatically under the control of the microprocessor

13. When the user needs high current test (such as 30 A), the instrument can be implemented by external power supply.

1.Measuring range ：0～5000Ω（Current pile impedance）

2.Resolution：0.001mΩ

3.measurement error ：±（reading ×2％+0.005Ω）

4.Anti-power frequency 50 Hz voltage interference ability：10V

5.Test current waveform：sine wave

6.Test current frequency：

Single frequency ：40-70Hz resolution ratio 0.1Hz Random settings

double frequency ： from 50±0.1Hz to 50±10.0Hz Random settings

From 60±0.1Hz to 60±10.0Hz Random settings

7. output current ：5A or external power supply 30A

8.Output voltage ：400V or 1000 V External

9.Measuring line requirements：

Cross section of copper core of current line≥1.5mm2

Cross-sectional area of copper core of voltage line≥1.0mm2

10.Test power：Built-in 2 kW frequency conversion power supply or external high power frequency conversion power supply.

11. Power Supply Voltage：AC220V±10％，50Hz

12.dimension：500mm*377mm*330mm Net weight ：20kg

1. In order to make the test go on smoothly, please use a multimeter to check whether the contact point between the test lead and the ground pile is intact, and measure whether the laid line is open.

2. The instrument will automatically eliminate wiring errors during the four-pole measurement.

3. When the cursor is on the current, press the "OK" button, a small printer symbol will appear or disappear in the lower left corner of the screen, representing the selection or cancellation of the automatic printing function

4. If there are other malfunctions in this instrument, please contact our company's after-sales service department directly, please do not disassemble and inspect it privately.

Note: The measuring line is configured by the user according to the size of the ground network

The reliability of the power station grounding design not only affects the safety and normal operation of various electrical equipment in the entire substation, but also affects the personal safety of the staff in the station. Therefore, in order to ensure the safety of the power station operation, the key is to improve the power station grounding design. reliability. The grounding resistance value of a power station is an important technical index of the grounding system of a power station and one of the important parameters to measure the effectiveness and safety of the grounding system. Accurate measurement of grounding resistance is of great significance to the safety evaluation of grounding grids. In order to ensure the safe and reliable operation of the power station, the grounding resistance value is required to be as low as possible. The measurement of the grounding resistance of the geodetic grid of a hydroelectric power station is more difficult because of the large number of environmental interference sources and the influence of the topography.

(1) Calculation principle of grounding resistance

The power frequency grounding resistance is the grounding resistance calculated according to the current passing through the grounding body as the power frequency current. Generally, when not specifically named, the grounding resistance refers to the power frequency grounding resistance.

The principle of grounding resistance measurement is shown in Figure 1. Two grounding bodies A and B are buried in the soil. There is a certain distance between AB. When the current flows through the grounding body and the earth to form a loop, a voltage is generated around the grounding body. The potential distribution has the following characteristics:

The farther away from the grounding bodies A and B, the lower the potential difference. When the distance reaches a certain level, the potential difference approaches zero, forming a zero-potential area CD. At this time, the relationship between voltage and current at each point is:

UAB=UAC+UDB=I(RA+RB) (1)

Where:

UAB—the voltage applied between grounding body A and B;

UAC—Voltage drop between A and C;

UDB—Voltage drop between D and B;

I—The total current generated by the applied voltage;

RA and RB are the grounding resistances of grounding bodies A and B, respectively.

Using the above principle, the ground resistance of A and B grounding bodies can be obtained:

RA= UAC/I (2)

RA= UDB/I (3)

In order to obtain UAC and UDB correctly, there must be a clear zero-potential zone. The smaller the zero-potential zone, the more difficult it is to correctly measure UAC and UDB. The size of the zero potential zone is related to the distance between the grounding body A and B, so the correct choice of the distance between A and B is the key to this measurement method. In addition, after the grounding body passes current, the potential distribution formed is also related to the shape, size and buried depth of the grounding body, which should be paid attention to when measuring. At present, the ground resistance measurement methods commonly used in the field include current and voltmeter method, compensation method and bridge method, etc. In actual measurement, the compensation method (0.618 method) is generally used to test the ground resistance for work.

The reliability of the grounding system of a power station is related to the normal operation of the entire power station. Therefore, when measuring and designing grounding resistance, it is necessary to select the appropriate measurement method and grounding method based on the actual situation. At the same time, the relevant departments cannot pursue convenient maintenance. Ignoring some details not only improves the reliability of the grounding system, but also saves investment costs.

Through the detection and analysis of the large-scale grounding grid of hydroelectric power stations, it is hoped that the analysis conclusion will play a certain guiding role in the detection of large-scale grounding grids in the future.