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Regular maintenance of DC resistance tester

time:2020/10/4   source:华天电力  reading:218 time

The DC resistance tester is an indispensable test item after the transformer is handed over, overhauled and the tap changer is changed. Under normal circumstances, the traditional method (bridge method and voltage drop method) is used to measure transformer windings and high-power inductance equipment The DC resistance is a time-consuming and labor-intensive work. In order to change this situation, shorten the measurement time and reduce the workload of testers, a rapid DC resistance tester was developed.


Transformer DC Winding Resistance Tester.png


Instructions for use of DC resistance tester:


Check whether the equipment is in good condition before use. And please check the product manual to confirm whether the accessories are complete;


After confirming the power supply voltage of the equipment, power on the equipment for self-check. Check whether the equipment can operate normally;


Refer to the connection method and operating instructions of the manual to conduct corresponding experiments and record the experimental data;


After the experiment, the cables were removed and boxed to clean the equipment. And do regular maintenance;


Note for DC resistance tester:


In the measurement process, in addition to strictly complying with the electrical safety regulations and equipment test regulations, special attention should also be paid to:


1) Measure when the coil temperature is stable. It is required that the temperature difference between the upper and lower parts of the transformer tank should not exceed 3°C;


2) Due to the inductance of the transformer coil, the charging current during measurement is not stable. Be sure to count after the current is stable, and take measures to shorten the charging time if necessary.


3) Minimize the wire contact resistance in the test circuit. The transformer taps in operation are often affected by dirt such as oil film to make their contact poor. Generally, it is necessary to switch several times before measuring, so as not to cause discrimination errors.


4) When measuring the low-voltage side of the transformer, all personnel should keep a proper safe distance from the high-voltage side.


5) The DC resistance tester should avoid strong vibration, direct sunlight and magnetic fields during transportation, storage and work. When storing and storing the instrument, pay attention to the ambient temperature and humidity. It should be placed in a dry, ventilated, and non-corrosive place. It should not be exposed to moisture, rain, or exposure to the sun. When using it, handle it gently, and do not drop it.


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