In power systems, the ground resistance test of large ground grids mainly adopts the power frequency high current three-pole method. To prevent power frequency interference 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 must not be less than 30 amperes. As a result, there are many problems such as bulky test equipment, complex test procedures, high labor intensity for test personnel, and long test time.
TPDWC-A Large Ground Grid Earth Resistance Tester is a new intelligent automatic anti-interference ground grid resistance tester launched by Tuopu Electric. This device can measure substation ground grids (4Ω), hydro and thermal power plants, microwave stations (10Ω), and lightning rods (10Ω) as a multi-purpose model. It adopts a new variable frequency AC power supply, and uses microprocessor control and signal processing measures, which effectively solves the anti-interference problem during the test, simplifies the test operation process, improves the accuracy and precision of test results, and greatly reduces the labor intensity and test cost of test personnel.
This instrument adopts heterodyne anti-interference technology, which can accurately measure data at 50Hz power frequency under strong interference environments. The maximum test current is 5A, which will not cause excessive potential rise of the grounding device during testing. At the same time, it has strong anti-interference capability, so measurement can be carried out without power outage.
TPDWC-A Large Ground Grid Earth Resistance Tester is suitable for testing the power frequency grounding impedance, contact voltage, step voltage, and other power frequency characteristic parameters of various grounding devices, as well as soil resistivity.
Features of Automatic Anti-interference Ground Grid Resistance Tester
1. Good power frequency equivalence:
The test current waveform is a sine wave, and the frequency differs from power frequency by only 5Hz. Measurements are made using 45Hz and 55Hz frequencies.
2. Strong anti-interference capability:
This instrument uses the heterodyne method for measurement, combined with modern software and hardware filtering technology, giving the instrument high anti-interference performance and stable and reliable test data.
3. High precision:
The basic error is only 0.005Ω, which can be used to measure large ground grids with very small grounding impedance.
4. Powerful functions:
Can measure current stake, voltage stake, grounding resistance, step voltage, and contact voltage.
5. Simple operation:
Full Chinese menu-based operation, directly displaying measurement results.
6. Low wiring labor, no need for large current cables.
Precautions
1. To ensure smooth testing, please use a multimeter to check whether the contact points between the test leads and ground stakes are intact, and check whether the laid wires have any open circuit before testing.
2. When using the four-pole method, the instrument will automatically eliminate wiring errors.
3. When the cursor is on the current, press the "Confirm" key once, and a printer symbol will appear or disappear in the lower left corner of the screen, indicating the selection or cancellation of the automatic printing function.
Technical Parameters
1. Impedance measurement range: 0～200Ω
2. Resolution: 0.001Ω
3. Measurement error: ±(reading ×2% + 0.005Ω)
4. Anti-power frequency 50Hz voltage interference capability: 10V
5. Test current waveform: sine wave
6. Test current frequency: 45Hz, 55Hz dual frequency
7. Maximum output current: 5A
8. Maximum output voltage: 400V
9. Measurement line requirements: current line copper core cross-sectional area ≥1.5mm2
Voltage line copper core cross-sectional area ≥1.0mm2
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
