The impact of currents harmonics over the voltage transformers from a power group

The paper presents the influence of a distorting element (D) from a power group over the lifetime of some test voltage transformers (T). D is a three phase rectifier fully controlled with thyristors and T are used to monitor the power group and measure the voltages across the main generator terminals. One presents the structure of the monitored power group´s components, focusing on the electric quantities that disturb the operation of T. A short description of the complex data acquisition system specially conceived for this purpose is provided. Recorded quantities corresponding to the voltages and currents from the main generator terminals are presented. Data corresponding to the currents recorded at the excitation transformer terminals are also analyzed. The recorded quantities are processed and the voltage/current harmonic components are presented as graphs or tables. One determined various categories of powers flowing through the main generator and respectively through the primary winding transformer. The power flow is distinctly considered along fundamental and respectively along higher harmonics. Significant conclusions are drawn with respect to their influence over the voltage transformers.