Voltage regulation with a dynamic voltage restorer using reactive power for low DC energy storage utilization

A single-phase dynamic voltage restorer that applies two functions for voltage regulation is proposed in this paper. Load voltage regulation using reactive power (RRP) is proposed to be used together with the classical restoration function using active power. The RRP function can be used to compensate swells, and some sag cases if the load power factor allows its possibility. The use of reactive power to regulate the load voltage means that no energy is needed to be provided from or absorbed by the capacitor bank energy storage. This is accomplished by making the compensation voltage to be in quadrature with the fundamental component of the system current. This gives a significant advantage, since the equipment can compensate swells without the need of regeneration, of the oversizing of the dc link, or of dissipation means; and can compensate sags without using the energy of the storage. For the sag cases where the RRP is not possible to apply, the classical restoration function using the active power of the energy storage is activated, injecting the missing voltage in back phase. Generation of references, limitations, a scheme of operation, and practical simulations results are presented. © 2009 Praise Worthy Prize S.r.l. - All rights reserved.

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