A Study of Transferred Overvoltages on the Secondary Windings of Station Service Voltage Transformers

Resumo

Station service voltage transformers (SSVTs) are finding increasingly wide application in world practice. One of the key issues of ensuring the reliable operation of the SSVTs is the coordination of their insulation and the protection against high-frequency overvoltage including that induced on the secondary windings. The paper presents the results of measuring the transfer functions and the oscillographic recording of the voltages on the SSVT secondary windings. The transferred overvoltage ratios of unloaded and loaded transformer secondary windings are estimated. Estimated rates of output-voltage increase at resonant frequencies are presented. The transferred overvoltage ratios on the SSVT primary windings under the impact of the damped oscillatory voltage are assessed.