This article introduces exceptional conditions of electronic voltage transformers for New Generation Smart Substation in Anhui among start-up process. By analyzing the recorded data, it is speculated that there are exceptions in voltage converters. Comparing the new waveforms with old ones from the voltage converter, the speculation is demonstrated. With the spectral analysis of waveforms using S-transform, it is further determined that poor performance of voltage converter directly leads to the above exceptions. Finally some reform measures are proposed to prevent this kind of exceptions.