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Detection Technology

The DC resistance tester makes a noise

time:2021/2/15   source:华天电力  reading:572 time

The DC resistance tester will produce a continuous "buzzing" sound when it is running. If the sound produced by the instrument is uneven or has other special noises, it should be regarded as an abnormal economic operation of the transformer, and system faults can be found according to different conditions. Analyze and deal with it in a timely and effective manner. The main faults are as follows:

1. When the power grid is over-voltage, single-phase grounding or electromagnetic resonance occurs in the power grid, the sound of the transformer is sharper than usual. When this happens, you can make a comprehensive judgment based on the instructions of the voltmeter.

2. Due to the overload operation of the transformer, the load changes greatly, and the DC resistance test instrument has intermittent "wow" or "creak" sound, and the pointer of the monitoring and measuring instrument swings, the pitch is high, and the volume is loud.

Transformer DC Winding Resistance Tester.png

3. Whether the transformer clips or screws are loose, the sound is louder than usual and there are obvious noises, but there is no obvious abnormality in the current and voltage, it may be caused by the loosening of the internal clips or the screws that press and fix the iron core. Vibration between traditional silicon steel sheets can be increased.

4. The transformer performs partial discharge. If the drop-out fuse or tap changer of the transformer can contact bad society, there will be a "squeaking" discharge sound. If the transformer bushing is dirty, the surface enamel will fall off or cracks Exist, you can hear the "hissing" sound. If the internal partial discharge of the transformer or the electrical connection is poor, the "squeaking" or "cracking" sound will be emitted, and this sound will change with the distance from the fault. At this time, The transformer should be deactivated immediately.

5. The transformer winding is short-circuited, the sound is mixed with the sound of water boiling, and the temperature changes rapidly, and the oil level rises. It should be judged as a short-circuit fault between the transformer windings. If it is severely affected, there will be a huge roar. Then we may Cause a fire, at this time, the transformer should be stopped immediately for analysis and inspection.

6. Flash discharge of the transformer shell. This sound will appear when the high voltage environment of the transformer winding causes the outgoing wires to flashover or discharge to the shell. At this time, a shutdown inspection can be performed for different transformers.

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