Table of Contents

Product Introduction

The HF-GT-219Variable Frequency Large Ground Grid Resistance Tester (400V) is a high-precision testing instrument used on-site at substations for measuring grounding resistance and related parameters. Equipped with a USB interface, it features compact size, light weight, easy portability, powerful anti-interference performance and high measurement accuracy.

Adopting an integrated structure with a built-in variable frequency power module, its output power supports continuous adjustable frequency (45Hz and 55Hz optional). Built around a high-speed processor core, it applies digital filtering technology to evade interference from power frequency electric fields, fundamentally solving the problem of inaccurate measurement under strong electromagnetic field conditions.

Extensive field tests and user feedback verify that it delivers stable, repeatable measurement data when testing grounding grids in harsh electromagnetic environments of operational substations. It serves as an ideal testing device for parameter measurement of medium and large-scale grounding grids.

Product Features

Full Touch Large-Size LCD Display

Extremely user-friendly operation with a full-touch LCD screen and full-graphic intuitive interface. All testing procedures are clearly displayed, so operators can conduct measurements without professional training. One-touch operation completes the whole test flow, making it an intelligent high-performance measuring device.

Variable Frequency Technology for Precise Measurement

Boasting superior anti-interference capability, the built-in variable frequency power supply provides testing output power at optional frequencies of 45Hz and 55Hz. Combined with digital filtering technology, it filters out all on-site power frequency interference signals to achieve highly accurate, stable and reliable measurement results.

High-Speed DSP Processor

It adopts a professional high-speed DSP digital signal processor as the core computing unit. While guaranteeing measurement precision, it greatly enhances the overall computing and processing efficiency of the instrument.

Fully Automatic Intelligent Control

Supported by the high-performance processing core, the instrument automatically completes all complex procedures including current output, voltage acquisition and frequency conversion throughout the test. It intelligently judges the impedance of the current loop and automatically adjusts the output current of the variable frequency power supply (rated output current: 5A). No manual intervention is required to finish the whole test.
Measurable parameters include total ground impedance Z, pure resistance component R and inductive reactance component X of the grounding grid.

Mass Data Storage Function

Equipped with a calendar chip and large-capacity memory, the instrument stores all test results chronologically. Historical records can be reviewed anytime and printed out on demand.

PC Data Processing via USB Interface

All measured data can be exported via USB flash drive, then viewed, analyzed and managed on a computer with the supporting dedicated software.

Technical Parameters: Variable Frequency Ground Grid Resistance Tester

Item	Technical Specifications
Rated Output Voltage	AC 400V
Rated Output Current	5A
Optional Working Frequency	45Hz / 55Hz (variable frequency anti-power frequency interference)
Measuring Range	Ground grid impedance: 0.01Ω ~ 200Ω
Measurement Accuracy	±2% reading ±1 digit
Measurable Parameters	Total ground impedance Z, resistive component R, inductive reactance X
Processing Core	High-speed DSP digital signal processor
Display Screen	Large full-touch LCD graphic display
Data Storage	Built-in large-capacity memory, chronological recording of test data
Data Export Method	USB flash disk export, supporting PC upper computer software analysis
Operation Mode	Fully automatic intelligent measurement, no manual parameter adjustment needed
Anti-interference Technology	Digital filtering + variable frequency isolation, adapts strong electromagnetic field substation site
Power Supply	Built-in rechargeable lithium battery / AC 220V mains power supply
Overall Structure	Integrated portable aluminum alloy chassis
Ambient Working Temperature	-10℃ ~ +50℃
Relative Humidity	≤85%RH (non-condensing)
Applicable Scenarios	Large & medium substation grounding grid parameter testing

FAQ – Variable Frequency Ground Grid Resistance Tester

Q1: What is a Variable Frequency Ground Grid Resistance Tester used for?

A1: It is specially developed for testing large and medium substation grounding grids. It accurately measures grounding impedance, resistance and reactance under strong electromagnetic interference on live substation sites.

Q2: Why use variable frequency technology instead of power frequency testing?

A2: It adopts 45Hz/55Hz adjustable frequency to avoid 50Hz power frequency interference. Combined with digital filtering, it effectively filters field stray signals and ensures stable and accurate test results in complex high-voltage environments.

Q3: What are the rated voltage and current?

A3: Rated output voltage is AC 400V and rated output current is 5A, which meets the testing requirements for large-scale grounding grids.

Q4: What parameters can this instrument test?

A4: It can measure total grounding impedance (Z), pure resistance component (R) and inductive reactance component (X) of the ground grid.

Q5: What is the measurement range and accuracy?

A5: Measurement range: 0.01Ω～200Ω; Basic accuracy: ±2% reading ±1 digit, fully compliant with international grounding test standards.

Q6: Is professional operation skill required?

A6: No professional training needed. Equipped with full-touch LCD screen and fully automatic testing program, it supports one-key test without manual parameter setting.

Q7: How does the automatic test work?

A7: Built-in high-speed DSP processor automatically controls frequency conversion, current output, signal acquisition and data calculation. It adaptively adjusts output current and completes the whole test intelligently.

Q8: Does the device support data storage and export?

A8: Yes. It supports large-capacity local data storage. Test records can be exported via USB, analyzed by PC software and used for standard test report printing.

Q9: Why are the test readings unstable and jumping?

A9: Unstable data is mainly caused by poor probe contact, loose wiring, damaged cables or strong surrounding electromagnetic interference. Reconnect the wires and test in a less disturbed area.

Q10: Why does the instrument show zero or negative values?

A10: This is normally caused by reversed wiring, low battery or broken test leads, not instrument failure. Please check connection and recharge the device before retesting.

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