Voltage control in low voltage systems with controlled low voltage transformer (CLVT)

The rapidly growing penetration of Germany´s distribution grids with all forms of DG causes a high pressure on voltage stability according to several normative guidelines. Beside conventional network reinforcements increasing short-circuit-power, new technical alternatives awake interest. One approach is the CLVT, an innovative downsizing of substations voltage regulation. This paper investigates the potential for voltage control of this new technology as well as the possibility to increase the DG connection capacity of LV networks with respect to step voltage, number of operating positions and which measurements are used as reference value for the controller. The benefits and disadvantages of an mono- and multi-sensor operation mode will be discussed. Furthermore possible interactions between several CLVTs connected to one single grid are analysed.