EN
- Description
- Specifications
- Applications
- Advantages
- FAQ
- Recommended Products
Description
The GDDT-40U is a high-current, high-precision intelligent ground continuity tester designed for measuring continuity resistance between grounding down-leads and main grounding grids in 110kV–500kV substations, power plants, and industrial sites. It adopts 40A constant current output and four-wire test method, eliminating contact resistance errors and ensuring accurate measurement of low-resistance connections.
Equipped with a 320×240 65K true-color TFT touch LCD, it provides intuitive graphical operation and clear visibility under strong sunlight. The high-speed MCU control enables fully automatic testing, while intelligent power management minimizes internal heating and extends service life. With 1000 groups of data storage, realtime clock, and RS232/USB communication, it supports data review, U disk export, and PC software analysis. Ideal for periodic maintenance, commissioning, and fault diagnosis of grounding systems to prevent hidden dangers caused by corrosion or poor contact.
Specifications
| Parameter | Specification |
| Test Current | 40A constant (5A/10A/20A optional) |
| Resistance Range | 1–1999mΩ |
| Resolution | 1mΩ |
| Accuracy | ±(1%×reading+1mΩ) |
| Test Method | Fourwire Kelvin |
| Display | 320×240 65K color TFT touch LCD |
| Data Storage | 1000 groups；掉电保存 |
| Communication | RS232 + USB；U disk export |
| Power Supply | AC220V±10%, 50Hz |
| Operating Temperature | 10°C ~ +40°C；Humidity ≤80%RH |
| Protection | Overcurrent, shortcircuit, reverseconnection, thermal shutdown |
| Dimensions (mm) | 300×270×200 |
| Weight | 5kg (excluding accessories) |
| Compliance | DL/T 4752006, JJG 9842004, IEC 610101 CAT IV 600V |
Applications
Core Test Objects
· Substation grounding down-leads: 10kV–500kV;between downleads & main grid
· Power plant grounding systems: thermal/hydro plants;equipment grounding connections
· Transmission tower grounding: 10kV–500kV tower downlead continuity
· Portable grounding wires: short-circuit & personal protection grounding wire resistance
· Industrial grounding grids: petrochemical, metallurgy, data centers
Typical Usage Scenarios
· Preventive maintenance: annual continuity testing of grounding downleads
· Commissioning: new substation/plant grounding system validation
· Fault diagnosis: corrosion, oxidation, loose connection, or broken downleads
· Live-site testing: works in energized substations with proper safety measures
· Compliance inspection: meets DL/T 475 & power industry safety standards
Advantages
40A High Current + 1mΩ Resolution
Penetrates oxide layers;accurate for low-resistance connections → detect hidden corrosion/poor contact
Four-Wire Kelvin Test
Eliminates test lead/contact resistance errors → true value measurement for critical grounding points
TFT Touch LCD + One-Key Operation
Intuitive interface;fast testing;no professional training → improve field efficiency
1000 Data Storage + PC Analysis
On-site record;data traceability;report generation → simplify maintenance & compliance
Compact & Portable
Lightweight;rugged design;field-ready → easy transport & deployment in substations
FAQ
Q: Can it measure rusted or oxidized grounding connections?
A: Yes. 40A high current penetrates oxide layers for accurate readings.
Q: Does it eliminate test lead resistance errors?
A: Yes. Four-wire Kelvin method cancels lead/contact resistance.
Q: How many test records can it store?
A: 1000 groups;supports U disk export and PC analysis.
Q: Is it suitable for live substation testing?
A: Yes;follow safety protocols for energized site operation.
Q: What’s in the standard package?
A: Main unit, 40A test cables (Kelvin clips), power cord, USB flash drive, carry case, manual, calibration certificate.
