This paper presents the new fundamental step-up method for standard voltage transformers (VTs) at the Physikalisch-Technische Bundesanstalt, as well as the setup of the required components. A main component is an active low-voltage capacitor, designed to realize capacitive voltage dividers by means of compressed gas, high-voltage capacitors for rated primary voltages between 5 kV and 800 kV/√ 3. This divider has a negligible voltage dependence and low phase errors at 50/60 Hz. Using the other components, mainly a two-stage VT with integrated inductive voltage divider and a sampling-based voltage comparator, a transfer uncertainty for one build-up step of below 1· 10⁻⁶ (k = 2) has been reached.