1、 Instrument Overview

At present, in the power system, the grounding resistance of the earth grid is mainly measured using the power frequency high current three pole method. In order to prevent power frequency interference during the operation of the power grid and improve the accuracy of measurement results, the insulation preventive test regulations stipulate that the test current of the power frequency high current method shall not be less than 30A. As a result, there are many problems such as bulky testing equipment, complex testing processes, high workload of testing personnel, and long testing times.

The grounding resistance tester for the earth network adopts a new type of variable frequency AC power supply and measures such as microcomputer processing control of the earth network grounding impedance tester and signal processing, which effectively solves the anti-interference problem during the testing process, simplifies the experimental operation process, improves the accuracy and precision of the test results, and greatly reduces the labor intensity and testing cost of the testing personnel.

The grounding impedance tester for the earth network is a specialized instrument used to measure the grounding resistance of the grounding network and the grounding continuity between the grounding points. The instrument adopts frequency conversion anti-interference technology, which does not require high current measurement and can accurately measure 50Hz data in strong interference environments of substations. The measurement results are displayed on a large LCD screen and come with a built-in micro printer for printing and output. The instrument can measure both grounding impedance and grounding resistance simultaneously, which can better reflect the actual characteristics of the grounding grid

2、 Functional Features

1. The measured power frequency equivalence is good. The test current waveform is a sine wave, with a minimum frequency difference of 0.1Hz and a maximum frequency difference of 10Hz from the power frequency. Can be used for measurement at two frequencies of 50Hz or 60Hz.

2. Strong anti-interference ability. This instrument adopts the frequency difference method for measurement, combined with modern software and hardware filtering technology, making the instrument have high anti-interference performance and stable and reliable test data.

3. High measurement accuracy. The basic error is only 0.005 Ω, which can be used to measure the earth network with very small grounding impedance.

4. Powerful functionality. It can measure current piles, voltage piles, ground grid impedance, grounding resistance, grounding conductivity, soil resistivity, etc.

5. Full touch LCD display screen, super comprehensive graphical operation interface, every process is very clear and understandable. Operators do not require additional professional training to use it. The entire testing process can be completed with a gentle touch.

6. Equipped with a calendar chip and large capacity memory, it can save results at any time. You can view the historical records at any time and print them out Both the current time and storage time can be displayed and printed.

7. Scientific and advanced data management: Instrument data can be exported through a USB flash drive, and can be viewed and managed on any PC through dedicated software. Capable of generating reports and experimental reports

8. Safe and reliable. The instrument has functions such as grounding protection, current and voltage limiting protection, and sound and light alarm to ensure the safety of testing personnel and equipment.

9. Equipped with vector testing function, capable of measuring ground impedance and ground pure resistance Impedance angle can be measured.

10. Low wiring workload, no need for high current wires.

11. Integrated model, equipped with standard resistors and constant current source for easy on-site testing and reducing on-site wiring.

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

When users need high current testing (such as 30A), this instrument can be implemented by connecting an external power supply.

3、 Technical indicators

1. Measurement range: 0-5000 Ω (including current pile impedance)

2. Resolution: 0.001m Ω

3. Measurement error: ± (reading x 2%+0.005 Ω)

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

5. Test current waveform: sine wave

6. Test current frequency: Single frequency: 40-70Hz Resolution: 0.1Hz, freely set

Dual frequency: freely set from 50 ± 0.1Hz to 50 ± 10.0Hz

Set freely from 60 ± 0.1Hz to 60 ± 10.0Hz

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

8. Output voltage: 400V or external power supply 1000V

9. Measurement line requirement: The cross-sectional area of the copper core of the current wire should be ≥ 1.5mm2

Voltage wire copper core cross-sectional area ≥ 1.0mm2

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

11. Power supply: AC220V ± 10%, 50Hz

12. Dimensions: 500mm * 377mm * 330mm Instrument weight: 20k