QLD-DB Earth Grid Grounding Resistance Tester

Functional Features

1. The power frequency equivalence of the measurement is good. The test current waveform is a sine wave, with a minimum frequency difference of 0.1Hz and a maximum of 10Hz from the power frequency. It can be used for measurement at either 50Hz or 60Hz.
2. Strong anti-interference ability. This instrument adopts the heterofrequency method for measurement and is combined with modern software and hardware filtering technology, which makes the instrument have a very high anti-interference performance and ensures stable and reliable test data.
3. High measurement accuracy. The basic error is only 0.005Ω, which can be used to measure the grounding impedance of large earth grids with very low resistance.
4. Powerful functions. It can measure current poles, voltage poles, ground grid impedance, grounding resistance, grounding conduction, soil resistivity, etc.
5. Full touch LCD screen, large full graphic operation interface, every process is very clear and understandable. Operators can use it without additional professional training. The entire process of testing can be completed with just a gentle touch.
6. It is equipped with a calendar chip and a large-capacity memory inside, which can save the results at any time. Historical records can be viewed at any time and printed out. Both the current time and the storage time can be displayed and printed.
7.  Advanced scientific data management: Instrument data can be exported via a USB flash drive and viewed and managed on any PC through dedicated software. Be capable of generating reports and test reports.
8. Safe and reliable. The instrument is equipped with grounding protection, current and voltage limiting protection, sound and light alarm and other functions to ensure the safety of the test personnel and equipment.
9. It is equipped with a vector testing function and can measure the impedance of the ground grid and the pure resistance of the ground grid. The impedance Angle can be measured.
10. The wiring labor is small, and there is no need for high-current wires.
11. Integrated model, equipped with standard resistors and constant current sources, facilitates on-site testing and reduces on-site wiring.
12. The instrument is easy to operate. 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.
13. When users need to test with a large current (such as 30A), this can be achieved by connecting an external power supply.

Technical Indicators

1. Measurement range: 0 to 5000Ω (including current pile impedance)
2. Resolution: 0.001mΩ
3. Measurement error: ± (reading × 2% +0.005Ω)
4. Resistance to 50Hz power frequency voltage interference: 10V interference suppression ratio: ≥60dB
5. Test current waveform: sine wave
6. Test current frequency: Single frequency: 40-70Hz, resolution 0.1Hz, set freely;Dual-frequency: Freely set from 50±0.1Hz to 50±10.0Hz;It can be set freely from 60±0.1Hz to 60±10.0Hz
7. Output current: 5A or 30A for external power supply
8. Output voltage: 400V or 1000V for external power supply
9. Requirements for the measurement line: The cross-sectional area of the copper core of the current line should be ≥1.5mm ²;The cross-sectional area of the copper core of the voltage wire is ≥1.0mm ²
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: 20kg

Instrument Principle

1. The resistance of the R0 loop is approximately 5 to 200Ω
2. The Rx test resistance is approximately 0 to 200Ω
3. Rf standard resistor
4. Measuring current line D: Its length should be 3 to 5 times that of the diagonal of the grounding grid. Wire diameter: ≥1.5mm ²
5. Measuring voltage line 1: Length 0.618D; Wire diameter: ≥1.0mm ²
6. Measuring voltage line 2: Connect to the grounding grid under test
7. Measure the grounding wire: grounding grid

Panel Introduction

1: Current pole (C1) 2: Voltage pole (P1) 3: Voltage pole (P2) 4: Grounding Grid (C2)
5: Current pole (C11) 6: Voltage Pole (P11) 7: Voltage Pole (P22) 8: Grounding Grid (C22)
9: External AC power supply 10: External AC power supply 11:232 Communication 12: Ground post 13: High-voltage switch 14:220V power socket 15: Power switch 16: USB flash drive Port 17: Printer 18. Liquid crystal screen
Note: Terminals 5,6,7,8,9 and 10 are only used when an external power supply is connected.
When using the internal power supply, just leave it suspended.

Measurement wiring

1. Measuring current line D: Wire diameter ≥1.5mm ², length 3 to 5 times the diagonal length of the grounding grid;
2. Measuring voltage line 1: A current line with a diameter of ≥ 1.0mm ² and a length 0.618 times.
3. Measuring voltage line 2: Connect to a certain down conductor of the grounding grid under test.
4. Measuring the grounding wire: Connect it to a certain down conductor of the grounding grid under test.

5. When using the four-pole method for measurement, two connecting wires are led out from the ground stakes of the ground grid and respectively connected to the voltage pole P2 of the instrument and the two terminals C2 of the ground grid. Then, the test is carried out according to the measurement operation steps.