The KGW-5A Large-Scale Ground Grid Ground Resistance Tester is designed to measure power-frequency grounding impedance, touch voltage, step voltage, transferred potential, surface potential gradient across the site area, and soil resistivity of various grounding systems. It can accurately test grounding grids of substations (≤4 Ω), thermal and hydroelectric power plants, microwave stations (≤10 Ω), lightning rods (≤10 Ω), and similar installations.

Employing advanced anti-interference technology with an off-frequency measurement method, the instrument ensures accurate acquisition of 50 Hz power-frequency data even in environments with strong electromagnetic interference.

With a relatively low test current (maximum 3 A), it prevents excessive rise in ground potential during testing. Combined with its exceptional noise immunity, measurements can be performed safely without de-energizing the system.

1. Excellent power-frequency equivalence: The test current waveform is a pure sine wave, with measurement frequencies of 45 Hz and 55 Hz—only 5 Hz away from the standard power frequency (50 Hz)—ensuring high fidelity to actual operating conditions.

2. Strong immunity to ground voltage interference: Utilizing an off-frequency (heterodyne) measurement method combined with advanced digital and analog filtering techniques, the instrument achieves exceptional anti-interference capability, delivering stable and reliable test data even in harsh electromagnetic environments.

3. High accuracy: With a basic error as low as ±0.002 Ω, it is capable of accurately measuring very low grounding impedances of large-scale grounding grids.

4. Comprehensive functionality: Fully compliant with relevant standards, it measures all characteristic parameters of grounding systems—not only grounding impedance but also its resistive and reactive components.

5. User-friendly operation: Features a fully Chinese menu-driven interface that directly displays measurement results for intuitive and straightforward use.

6. Minimal wiring effort: Requires no heavy-gauge high-current cables, significantly reducing setup labor and complexity.

7. Compact and portable: Small in size and lightweight, making it easy to transport and ideal for field applications.

I. Ground Impedance Technical Specifications

1. Impedance Measurement Range: 0 – 200 Ω
2. Resolution: 0.001 Ω
3. Measurement Accuracy: ±2% ±2 digits
4. Immunity to Ground Voltage Interference: A 15 V power-frequency interference voltage introduces an error of only 0.002 Ω
5. Test Current Waveform: Sine wave
6. Test Current Frequencies:
7. Single-frequency options: 45 Hz, 50 Hz, 55 Hz, 60 Hz, 65 Hz
8. Auto dual-frequency modes: 45/55 Hz, 55/65 Hz, 47.5/52.5 Hz
9. Maximum Output Current: Selectable levels: 0.5 A, 1 A, 1.5 A, 2 A, 2.5 A, 3 A, 3.5 A, 4 A, 4.5 A, 5 A
10. Maximum Output Voltage: 400 V
11. Test Lead Requirements:
12. Current leads: copper conductor ≥ 1.5 mm²
13. Voltage leads: copper conductor ≥ 1.0 mm²
14. Power Supply: AC 220 V ±10%, 50 Hz ±1 Hz
15. Operating Environment: Temperature: 0°C – 40°C; Relative Humidity: <90%
16. Dimensions (W × D × H): 440 × 350 × 210 mm
17. Instrument Weight: 8.5 kg

II. Soil Resistivity Technical Specifications

1. Measurement Range: 0 – 1000 Ω·m (ohm-meter)
2. Measurement Accuracy: ±2%
3. Resolution: 0.01 Ω·m