DC resistance test is a very important test item after transformer handover, overhaul, and tap changer replacement. It refers to the resistance of the buried grounding body and the resistance of soil stray current. In general, using traditional methods (bridge method and voltage drop method) to measure the DC resistance of transformer windings and high-power inductance equipment is time-consuming and labor-intensive. Usually, a tester is used for measurement, which can effectively improve product quality and prevent power supply accidents. It consists of a high-power switching power supply circuit, a precision small-signal measurement circuit, a protection circuit and a high-speed single-chip control circuit. It has the functions of instrument self-checking, signal measurement, data processing, rapid discharge, and printing results.
The application of the ground resistance tester are complex, and scientific applications need to be combined with the actual environment. If the influence of external environmental factors cannot be avoided, it will affect its use effect. For example, in a strong electromagnetic interference environment, it may cause command miscommunication or protection malfunction. Therefore, special attention should be paid to the environmental requirements of the tester.
In short, as the scale of the power system increases, the application range of ground resistance testers is becoming wider and wider. In order to ensure the safe operation of the power system, more attention should be paid to the tester, common faults should be eliminated, and corresponding preventive measures should be taken to reduce the cost of inspection and maintenance, truly guarantee the continuous supply of power energy, and ensure the smooth development of social activities.
