Research Of A New Type Quickly Measuring Instrument For The DC Resistance Of Transformers' Windings

Transformers are widely used in the power system. The measurement of the DC resistance of transformers' windings has great importance in checking their quality as their being manufactured, finding their defects on the operating spot, and analyzing and deciding faults after they failed. The IEC standards and national standards both have corresponding items about the measurement of DC resistance of transformers' windings.During the measuring of the DC resistance of a transformer's winding, the winding is equivalent to a resistance-inductance series circuit. Because power transformers often have big inductance but small resistance, they usually have big characteristic time. This result in the fact that the traditional measuring methods cost too much time before getting the result, and thus bring about much inconvenience, so quickly measuring method is needed to be found..In this paper, based on the analyzing and comparing of existing measuring methods, according to the inherent characteristics of transformers' windings, from the basic circuit, a new quickly measuring method that calculates the DC resistance of the transformers' windings during the transient process is deduced. The new method is quick, simple and accurate. And then, the design of hardware and software of the MCU centered intelligent instrument solution is prescribed in this paper.The paper is divided into 5 chapters. In cheaper 1, the purpose of measurement of DC resistance of transformers' windings and the work done in this paper are briefly described. The deduction of the new quickly measuring method is described in chapter 2. In chapter 3, the hardware design of the intelligent instrument is described. And the software design of the intelligent instrument is described in cheaper 4. In chapter 5, the work done and the deficiency of the instrument and further work to be done are discussed.