EN
GDHL-100A Intelligent Loop Resistance Tester（100A DC, 0.01μΩ Resolution, Four-Terminal）
GDHL-100A Digital Intelligent High‑Precision Loop (Contact) Resistance Tester with 100A DC Constant Current, Four‑Terminal Sensing, Long‑Duration High Current, for HV Switchgear & Busbar Micro‑Ohm Measurement.
- Description
- Specifications
- Applications
- Advantages
- FAQ
- Recommended Products
Description
GDHL-100A is a professional high‑current micro‑ohmmeter designed for measuring contact/loop resistance of high‑voltage switchgears, circuit breakers, busbars and cable joints in power systems. It strictly complies with DL/T 845.4‑2004, IEC 62271‑100 and GB/T 10230 standards, and outputs 100A DC constant current as required by the latest power equipment preventive test regulations.
Adopting high‑frequency switching power supply + 16‑bit Σ‑Δ ADC technology, the instrument features 0.01μΩ ultra‑high resolution and ±(0.5% reading + 2 digits) accuracy. The four‑terminal Kelvin measurement completely eliminates lead resistance interference. Long‑duration 100A current burns off switch contact oxide films, ensuring true and stable readings.
Specifications
| Parameter | Specification |
|---|---|
| Compliance Standards | DL/T 845.4‑2004, IEC 62271‑100, GB/T 10230 |
| Test Current | DC 100A (constant current, ripple ≤0.1%) |
| Resistance Range | 0–1999.9μΩ (max 99mΩ with extended cables) |
| Resolution | 0.01μΩ (0–99.99μΩ); 0.1μΩ (100–1999.9μΩ) |
| Accuracy | ±(0.5% reading + 2 digits) |
| Open‑Circuit Voltage | ≥10V DC |
| Test Duration | 5s–599s (adjustable) |
| Display | 4.7” color LCD, high brightness, sunlight readable |
| Operation | Touch key, Chinese/English bilingual |
| Data Storage | 1000 groups (with time stamp & ID) |
| Printer | Built‑in thermal printer (57mm width) |
| Interface | USB 2.0 (data export) |
| Power Supply | AC 220V±10%, 50Hz±2Hz, ≤150W |
| Operating Temperature | ‑10℃ ~ +50℃ |
| Humidity | ≤85% RH (non‑condensing) |
| Dimensions (L×W×H) | 290×280×240mm |
| Weight | ~6.5kg |
| Enclosure | Aluminum alloy, IP54 |
Applications
Core Test Objects
- HV circuit breakers: Vacuum, SF6, oil breakers (6–500kV)
- Switchgears: Contact resistance of main contacts & busbar joints
- Cable systems: Conductor resistance & welded joint resistance
- Earthing switches & disconnect switches: Loop resistance verification
Typical Usage Scenarios
- Power companies: Substation preventive maintenance & fault diagnosis
- Switch manufacturers: Factory quality control & type tests
- Power plants: Generator switchgear & auxiliary equipment testing
- Industrial enterprises: High‑current equipment maintenance & safety inspection
Advantages
Compliance with Latest Standards
Fully meets DL/T 845.4‑2004, IEC 62271‑100 → test results are globally recognized
100A True DC Current
100A constant current ensures accurate simulation of actual operating conditions for switch contacts
Four‑Terminal Eliminates Lead Error
Kelvin method removes cable resistance interference → readings are stable and repeatable
Oxide Film Burning
Long‑duration high current burns oxide layers → measures true contact resistance
All‑in‑one Data & Report
Storage, print, USB export & one‑click reports → simplifies on‑site documentation
FAQ
Q: Why 100A instead of lower current?
A: Power industry standards require ≥100A for loop resistance testing. Lower currents (5–10A) cannot break contact oxide films, leading to false high resistance readings.
Q: How does four‑terminal wiring help?
A: The Kelvin method separates current injection and voltage sensing leads, completely eliminating resistance error from test cables (typically 5–50mΩ).
Q: Can it measure very low resistance (≤1μΩ)?
A: Yes. With 0.01μΩ resolution and 100A current, it accurately measures 0.1–1μΩ contact resistance in high‑current switchgear.
