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Detection Technology

Solution of Resistance Tester Inaccurate Reading

time:2019/12/18   source:Huatian Electric Power  reading:996 time

In the earth resistance test, what are the reasons for the inaccurate reading of the earth resistance testeralso known as earth resistance detection deviceand how to solve them?

1. Since the grounding resistance measuring instrument is used to measure the ground resistance of the ground body by transmitting and receiving the current from the iron solder, so if the distance between the two iron solders and the two iron solders are too close to the ground body, interference will occur and error will be generated, therefore, the grounding body, the voltage pole and the current pole should be arranged in sequence during the measurement, and the three points should be arranged in a straight line, 20 meters apart from each other, so as to avoid this problem.

2. The depth of the iron solder should be greater than 1/4 of the length of the iron solder, otherwise, the test error will be generated, so try to drill the iron solder as deep as during the test.

3. Due to the poor insulation or short circuit of the equipment, the grounding device produces a certain ground voltage to the earth, which makes the reading unstable during measurement. At this point, the power should be cut off for detection, or disconnect the disconnect card for detection, to avoid the influence of the ground voltage on the detection.

4. Poor contact is also one of the causes of inaccurate reading, the measured object rust. When testing, it will find the phenomenon of time-off and on-off or large resistance. At this time, the first step is to remove rust. If not, check the conductivity of the testing line with the resistance of the grounding resistance measuring instrument.

5. When testing high-rise buildings, use too long, too thick line, so that line resistance and induced voltage increase and cause measurement error, should use wire resistance is lower, as far as possible to reduce the measurement error.

6. When the test environment has cushion soil layer, the resistivity of the two layers of soil is different, which is easy to cause the measurement error. Make it fully contact with the soil under the cushion or avoid the cushion, reduce the measurement error.

7. When the tested grounding device and metal pipe and other metal objects buried more complex, may change the current direction of each pole of the measuring instrument, resulting in poor or unstable measurement. It is necessary to first understand the layout of the grounding device and metal pipe, and choose the place with relatively small impact for measurement.

8. The surface of the potential difference or strong magnetic field, easy to cause the measurement is not accurate, so the measurement should be as far away from the potential difference or strong magnetic field. If unavoidable, the detection line should be shortened to reduce the measurement error.

9. If not according to the manual operation, grounding resistance tester fault not timely maintenance, earth resistance tester is inaccurate or no appraisal factors such as for a long time, can also cause measurement error, so during the test, the earth resistance tester is in accordance with the manual operation, daily maintenance of the grounding resistance tester is also very important.

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