1、 Purpose and characteristics of the instrument

The reliable and effective connection between the grounding down lead of power equipment and the grounding grid is the fundamental guarantee for equipment operation. The grounding down lead is the connecting part between the power equipment and the grounding grid. During the long-term operation of the power equipment, the joint may be corroded or even broken due to factors such as moisture, resulting in the increase of the resistance at the connecting point between the grounding down lead and the main grounding grid, which can not meet the requirements of the power regulations, resulting in hidden dangers in the operation of the equipment, In severe cases, it will cause the equipment to lose ground and operate. Therefore, in the 25 key requirements for preventing major accidents in power production, it is clearly proposed that the continuity detection of the down lead of grounding device should be carried out once a year.

The grounding down lead continuity tester is a portable tester with high automation developed by our company, which is used to measure the on resistance between the grounding down leads of various power equipment in the substation. The instrument is controlled by high-performance single chip microcomputer, which can realize the intellectualization of the test process. It has the advantages of small volume, convenient carrying, simple operation, high precision, fast test speed, good retestability and intuitive reading. It is an ideal instrument in line with the requirements of the regulations.

2、 Main technical indicators

U test current: 10a, 5A, 3a, 1a, 0.3A, automatic gear, six gears in total;

U measurement range: 10A: 1.0m Ω ～ 0.6 Ω

5A ：5.0mΩ～2.0Ω    

3A ：10.0mΩ～5.0Ω  

1A ：30.0mΩ～15Ω 

0.3A ：100.0mΩ～50Ω

Automatic gear: 1.0m Ω ～ 50 Ω

U small resolution: 0.0001 μ Ω。

U accuracy: ± (0.2% + 1 μ Ω word).

U display: liquid crystal display, resistance display, and the effective number is 5 digits.

U data storage: 500 groups.

U working environment: ambient temperature: 0 ℃ ~ 40 ℃, relative humidity: < 90% RH, no condensation.

U power supply: built in lithium battery, AC 220V ± 10V, 50Hz ± 1Hz, fuse 2A.

U large power consumption: 80W.

U host size: 243mm long × Width 154mm × Height 103mm

U host weight: instrument: 3.8kg.

U test line box weight: 8.5Kg.

3、 Functional features

L the instrument adopts two power supply modes: ① AC100-240V power supply; ② The instrument is powered by lithium battery, which solves the problem that it cannot be tested on site due to no power supply; Easy to use.

L the instrument has automatic test function (blind test), without selecting current gear;

L the test process is controlled by the host, which automatically completes self calibration, steady current judgment, data processing and resistance value display;

L it has the functions of charging and power display, and adopts high-capacity lithium battery (12.6V / 10A) to meet the needs of field test;

L the instrument is integrated with the test line packaging, with simple operation, fast measurement speed and stable measurement data;

L high precision, anti-interference, shockproof and easy to carry;

L adopt 5.0-inch 65K color LCD screen, intelligent touch, windows menu operation prompt;

L built in large capacity nonvolatile memory, which can store 500 groups of measurement data and can be consulted at any time.

L built in high-precision real-time clock function: date and time calibration;

L with USB flash disk storage function;

L it has the function of regular shutdown;