Transformer Response to System Switching Voltages

A section of an actual power system was modelled on a Transient Network Analyzer for the purpose of defining high frequency transient voltages occuring during switching events. The variety of system switching events which were staged produced oscillatory voltages covering a broad band of frequencies. On a digital model of the system autotransformers it was demonstrated that such oscillatory voltages could excite internal natural frequencies, but none of the actual generated waves coincided closely with the particular transformer natural frequency. However, if the applied waveshapes were frequency-scaled to a closer match, internal response voltages of concern could be developed.