Primary sources for fast and efficient checking of VT´s and CT´s secondary circuits

The authors detail the method developed and practiced by Eletronorte for checking CT´s and VT´s secondaries through potential and current primary injection when commissioning substations and power plants. The chief aim of the method consists in verifying in a dynamic simultaneous way if the CT´s and VT´s secondary circuits are properly connected, if the AC measuring devices and protection relays are correctly polarized and expeditiously confirm if those devices are operating according to their ranges and settings. To achieve all these features, dynamically and simultaneously, the authentic working and actuating parameters are reproduced. The method also takes into account some alternatives applicable to substations of the Eletronorte network where inherent voltage/current adjusting facilities are not available. In this case, the use of auxiliary transformers, or even diesel generators is proposed