Secondary Voltage Regulation (SVR) is part of the hierarchical control system of EHV transmission network, currently operated by the Italian Independent System Operator. SVR is being actuated using automatic voltage and reactive power regulators, named SART, in power stations rated more than 100 MVA. Each SART receives from the Regional Voltage Regulator a reactive level signal and implements it by controlling the reactive power of plant generators, in a balanced way. In this paper, hardware and software architectures of the SART version developed by the authors (NewSART) are presented. NewSART implements control and communication functions using an opensource Real Time Operating System installed on an industrial PC. Such a platform takes advantage of the availability of highlevel development tools and complete communication software libraries. The paper presents the design and principle schemes of the NewSART, along with experimental results of tests carried out during a SVR commissioning campaign.

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This paper proposes an application of a hierarchical automatic voltage regulation scheme for wind power plants connected to HV networks. The proposed control schemes is based on a given topology of wind power plants. In particular, we assume that wind generators are connected to each other and have a unique point of contact at the HV level. The secondary voltage control scheme proposed in the paper is based on well-assessed control strategies that are used in HV transmission systems, but has not been applied so far to medium voltage networks. A case study based on a wind power plant composed of 14 wind turbines and a distribution grid is presented and discussed in details

Distributed Generation (DG) operating in a distribution network influences active power losses. In this paper power losses have been estimated for an actual low voltage distribution network and compared for different situations according to the DG penetration and placement of the power units. A practical method to place new DGs is presented. The basic idea is to minimize power losses, while complying voltage network limits, calculated with power flows using historical data over a discrete number of possible points of connection