| Transformers play a key role in electric power system. The safe running of transformers is of great importance for ensuring the normal running of electric power system. The rate of transformer failures caused by the winding for deformation remains high. So the on-line monitoring of the condition of transformer windings is of great importance to find out hidden trouble of transformer in time so as to avoid outburst accident and improve safety and reliability of transformer operation.It is shown from the theoretical analysis of transformer that the short-circuit reactance of a transformer is decided by the size and the relative location of its windings. If a running transformer is suffered from short-circuit, the size and the relative location of its windings may vary. The value of the short-circuit reactance vary correspondingly. So the deform extent can be estimated by measuring, computing the short-circuit reactance and comparing its changes.In this paper two kinds of on-line monitoring methods are discussed, which are based on measuring primary, secondary currents and voltages to calculate the short-circuit reactance of windings. Thereby the on-line monitoring the deformation windings of transformer is implemented. The accuracy will not fall when the three phases are unequal, because the methods are based on the voltages and currents of each phase.Based on the theory above, a set of on-line detecting system on power transformer winding deformation using TMS320F206 micro controller unit is developed. The system can perform data acquisition, calculating and displaying the result of measurement, and communication with the PC. The hardware and software design methods of this system was introduced in this paper. The error analysis is also presented. Finally some simulations and calculations are carried out. The results show the methods are of high accuracy, which can meet the demand of the monitoring system. |
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