MS-300D Ground Grid Earth Resistance Tester Product Use
MS-300D Ground Grid Earth Resistance Tester is suitable for testing various grounding devices, ground grid power frequency grounding impedance, and other power frequency characteristic parameters, as well as soil resistivity in substations of 35kV and below.
It is used in various environments such as substation ground grids, thermal and hydro power plants, microwave stations, and lightning rods (150Ω).
Ground Grid Earth Resistance Tester adopts heterodyne anti-interference technology, which can accurately measure data at 50Hz power frequency under strong interference environments. The output voltage is as high as 400V, with strong load capacity, and the test current is 5A, which will not cause excessive potential rise of the grounding device during testing. It also has strong anti-interference capability, so measurement can be carried out without power outage.
Currently, in the power system, the testing of ground grid grounding resistance mainly uses the power frequency high current three-pole method. In order to prevent power frequency interference generated during grid operation and improve the accuracy of measurement results, the insulation preventive test regulations stipulate that the test current for the power frequency high current method shall not be less than 30A. As a result, problems such as bulky test equipment, complex test procedures, high labor intensity for testers, and long test duration have emerged.
According to industry standard DL/T475-2006 "Guidelines for Measurement of Characteristic Parameters of Grounding Devices (Revised Draft)" and national standard GB/T17949.1-2000:
Power frequency grounding impedance refers to the ratio of the potential difference between the grounding device and the remote zero potential point to the power frequency current flowing into the ground through the grounding device.
Power frequency grounding impedance was previously commonly referred to as "power frequency grounding resistance".
Ground Grid Earth Resistance Tester uses AC current for testing, so the measured value is called grounding impedance, and the previous term "grounding resistance" is no longer used.
The Ground Grid Earth Resistance Tester has the following features:
1. Good power frequency equivalence. The test current waveform is sinusoidal, with a frequency only 5Hz different from the power frequency, using 45Hz and 55Hz for measurement.
2. Strong anti-interference capability. This instrument uses the heterodyne method combined with modern software and hardware filtering technology, giving it high anti-interference performance and stable, reliable test data.
3. High accuracy. The basic error is only 0.005Ω, making it suitable for measuring large ground grids with very small grounding impedance.
4. Powerful functions. It can measure current stake, voltage stake, grounding resistance, step voltage, and touch voltage.
5. Simple operation. Full Chinese menu-based operation, directly displaying measurement results.
