Modeling, Testing and Configurating a Transformer for LV Active User Voltage Regulation

The increasing presence of distributed energy resources in low-voltage networks requires for a revision of the regulation criteria adopted in these networks for voltage control. In particular, voltage quality at active users' premises should be guaranteed by devices that must be fast-acting, cheap, easy to be installed, small and with reduced weight. In addition, these devices must not reduce the reliability of both the users and the network. In this paper, firstly a comparison of the main solutions for voltage regulation present in the literature is performed. Then the proposal of a new simple, economical and compact device for supporting voltage control at low voltage users' premises is presented. In particular, the device is composed of a transformer whose winding configuration is changed by static switches. In this paper, the transformer is adequately modeled and the results of various tests on a prototype are presented to evaluate the model parameters and to validate the model under actual operating conditions. Finally, model simulations are used to choose the configurations of the transformer windings so as to guarantee adequate voltage quality at users' premises while minimizing the number of static switches to be used.