At present, in power system, the grounding resistance of large grounding grid is mainly measured by power frequency and large current triode method. In order to prevent power frequency interference and improve the accuracy of measurement results, the rules of insulation preventive test stipulate that the test current of power frequency high current method should not be less than 30 amperes. As a result, many problems arise, such as heavy test equipment, complex test process, high work intensity of test personnel, long test time and so on.

HYG-5A earth grid grounding resistance tester can measure multi-purpose machines of substation grounding network (4), hydrothermal power plant, microwave station (10) and lightning rod (10). A new type of variable frequency AC power supply is adopted, and some measures such as computer processing control and signal processing are adopted to solve the anti-interference problem in the test process, simplify the test operation process and improve the precision of test results. The degree and accuracy greatly reduce the labor intensity and test cost of the test personnel.

This instrument is suitable for testing power frequency characteristic parameters such as power frequency grounding impedance of various grounding devices and soil resistivity. The instrument adopts the technology of anti-interference with different frequencies, and can accurately measure the data at 50Hz power frequency under strong interference environment. The maximum test current of 5A will not cause the grounding device potential to be too high during the test. At the same time, it also has strong anti-interference ability, so it can be measured without power failure.

Main Functional Characteristics

According to the requirements of DL/T475-2006 Guidelines for Measuring the Characteristic Parameters of Grounding Devices, in order to reduce the influence of power frequency current interference in the grounding network, when measuring power frequency current, the test current should be above 50A. Such high current power supply and cable are very heavy, which causes a great deal of invariability to the test. The advantage of frequency conversion measurement is that the anti-interference effect of power frequency interference can be achieved or surpassed by using a small test current by using frequency conversion technology. Therefore, the guideline stipulates that the current measured by frequency conversion can be reduced to 3A. The frequency selective voltmeter and the earth grid grounding resistor produced by us can meet all the test requirements stipulated in the guidelines. The instrument is very portable and can greatly reduce the intensity of field measurement.

The key to realize anti-jamming measurement is to suppress the interference signal. The frequency selective voltmeter adopts high precision adaptive digital notch filter technology, which can automatically track and suppress the interference frequency. The theoretical suppression ability of the algorithm is close to one millionth. Compared with some imported frequency selective voltmeters, the existence of interference can be neglected in frequency selective voltmeters.

Main Technical Indicators

Measuring range: Accuracy of 0-600V: +(Reading x 1%+0.1mV)

Maximum resolution: 0.001 mV

Input impedance: > 500K Human body analog resistance: 1500_+5%

Measuring Frequency: Corresponding to Ground Resistor Instrument of Ground Grid, Interference Suppression Ratio: > 80dB

Battery working time: about 8 hours charging time: about 3 hours >

Charging power supply: 220V + 10%, 50Hz / 60Hz

Weight: 0.5kg

1. The power frequency equivalence of measurement is good. The test current waveform is sinusoidal, and its frequency is only 5 Hz different from that of the power frequency. It is measured by using 45 Hz and 55 Hz frequencies.

2. Strong anti-interference ability. This instrument adopts the different frequency method to measure, and cooperates with the modern software and hardware filtering technology, which makes the instrument have high anti-interference performance and stable and reliable test data.

3. High accuracy. The basic error is only 0.005_, which can be used to measure large-scale grounding network with small grounding impedance.

4. Powerful function. It can measure grounding resistance of current pile, voltage pile, grounding resistance of grounding grid, conduction resistance and soil resistivity. External special frequency selector can measure step voltage and contact voltage. It can also measure surface potential gradient. It has stronger anti-interference ability and higher precision.

5. Simple operation. All Chinese menu operation, directly showing the measurement results.

6. Small amount of wiring work, no need for large current lines.