Gianluca Sapienza

Automatic Distributed Voltage Control Algorithm in Smart Grids Applications

The widespread use of distributed generation (DG), which is installed in medium-voltage distribution networks, impacts the future development of modern electrical systems that must evolve towards smart grids. A fundamental topic for smart grids is automatic distributed voltage control (ADVC). The voltage is now regulated at the MV busbar acting on the on-load tap changer of the HV/MV transformer. This method does not guarantee the correct voltage value in the network nodes when the distributed generators deliver their power. In contrast, the ADVC allows control of the voltage acting on a single generator; therefore, a better voltage profile can be obtained. In this paper, an approach based on sensitivity theory is shown to control the node voltages regulating the reactive power injected by the generators. After the theoretical analysis, a numerical example is presented to validate the theory. The proposed voltage regulation method has been developed in collaboration with Enel Distribuzione S.p.A. (the major Italian DSO), and it will be applied in the Smart Grids POI-P3 pilot project, which is financed by the Italian Economic Development Ministry. Before the real field application in the pilot project, a real-time digital simulation has been used to validate the algorithm presented. Moving in this direction, Enel Distribuzione S.p.A. built a new test center in Milan equipped with a real-time digital simulator (from RTDS Technologies).

Petersen Coil Regulators Analysis Using a Real-Time Digital Simulator

In order to study new technologies, in sight of smart grids, and for new regulation, protection, and control devices homologation tests, it becomes essential to use a real-time digital simulator (RTDS). This calculator offers the possibility to analyze the behavior of the aforementioned devices in any electrical grid condition, especially those hardly reproducible on the real field. In this paper, the analysis of two types of Petersen Coil Regulators will be discussed, focusing on the experimental results reached, useful to gain an optimized electrical distribution grid management.

Robust Real-Time Load Profile Encoding and Classification Framework for Efficient Power Systems Operation

Neatly represented and properly classified load profiles are fundamental to many control optimization techniques of modern power systems, especially in a distribution area. This paper presents a novel load profile management software framework for boosting the efficiency of power systems operation. The proposed framework encodes and classifies load profiles in real-time. Imperfections as well as time-shifts in the input (measured power consumption levels) are tolerated by the suggested system, thus always providing accurate, fast and reliable output. The frameworks fully component based structure allows easy customizations of the encoding as well as the classification engines. The default encoding engine is based on an artificial neural network, a variant known as a deep learning auto-encoder comprised from stacked sparse auto-encoders. The default classifier engine is based on an implementation of a locality sensitive hashing algorithm. The developed methodology was tested on the real case of a set of anonymous customers supplied by a power distribution company. The paper also contains an elaboration about the experiences gained during the design, implementation and testing phase of this system as well as a detailed engineering use case of the frameworks applicability.

Real time simulation of Smart Grids for interface protection test and analysis

The widespread of the Distributed Generation (DG) impacts the future development of modern electrical distribution systems that must to evolve towards Smart Grids. Fundamental topics of the Smart Grid context are the Distributed Voltage Automation and the Advanced Network Automation based on fast communication channels. In order to analyze the behavior of a network which evolves in Smart Grid, real time digital simulation, using a closed loop system, is an indispensable approach because allow to study normal and critical situations that can happen in the grid. Besides the interaction with real devices can be performed, in order to verify their correct operation. In this paper, after a general description of the real time simulation in the Smart Grid context, the behavior analysis of an interface protection device is performed using the Real Time Digital Simulator (RTDS) installed in the Enel Distribuzione S.p.A. test centre.

Distributed generation regulation for intentional islanding in Smart Grids

The many new installation of generators, often based on renewable sources, in the distribution grids impacts the future development of modern electrical distribution systems that must to evolve towards Smart Grids. An important function required by the future smart grids is the possibility to maintain an intentional island using a suitable control of the distributed generator. In this paper, after a general description of the real time simulation in the Smart Grid context, the behavior analysis of the grid with generators PQ controlled and PV controlled has been carried out using the Real Time Digital Simulator (RTDS) installed in the Enel Distribuzione S.p.A. test center.

Electrical energy storage in Smart Grid: Black-start study using a real-time digital simulator

The future development of modern electrical systems must to evolve towards Smart Grids. The Smart Grids context involves several players and automation functions, such as Distributed Generators with their related controls, Intelligent Load Management, Smart Metering, infrastructures for Electric Mobility, Energy Storage, etc. In particular an Energy Storage system favors the connection of renewable generators and can improve the network stability. Moreover it can be used to energize a portion of a grid in islanding operation in case of loss of mains. This function is so-called black-start. This paper analyzes the new Energy Storage system installed by Enel Distribuzione S.p.A. in the center of Italy into the “Isernia Pilot Project” on Smart Grids, for the operation in black-start mode. The study is performed using the RTDS real-time digital simulator, in order to qualify the best way to perform the blackstart.

Uncontrolled islanding operations of MV/LV active distribution networks

In many countries different technical rules have been introduced in order to integrate the DG units in the medium voltage (MV) and low voltage (LV) distribution network. New standards state requirements for all generators, included inverter based ones, imposing a Fault Ride Through (FRT) philosophy and new active and reactive power regulation actions with the aim of maintaining the transmission system stability at the level it was with traditional rotating generators, or even increasing it. These technical rules may not be fully compliant with the automatic reclosing cycle usually performed from the CB at the beginning of MV feeders and/or with the automatic procedure of faulty section selection and supply restore to healthy ones. In this paper the effects of DG units connected at MV and LV voltage level in relation to different fault conditions are analyzed. The possibility of temporary uncontrolled islanded operations are investigated in order to evaluate the role of new Standards or Regulatory or Law requirements in the automatic reclosing procedure and MV network automation.

Testing 750 node distribution grids and devices

The use of a real-time simulator helps Enel Distribuzione to verify their protection schemes and protocols as well as to study the smart grid concepts required to run their grid effectively and reliably.

Power quality analysis of electromechanical energy conversion: A Budeanu approach

The concept of magneto-electric root mean square (RMS) is extended to the motional cases, where electromechanical energy conversion processes are concurrently present. Emerge, with undiminished physical meaning, the concepts of mechanical RMS of force ƒ(t) and velocity u(t).

Voltage profile calculation in Distribution Networks under sinusoidal and distorted operation

Due to the growth of Distributed Generation, also in Low Voltage Distribution Networks, in which single-phase generators may be connected to the grid, the voltage calculation it is necessary for each phase of the system. This is an important issue because an non-uniform connection of the single-phase generations on the three phases causes voltage imbalances along the feeders. Moreover, harmonic current injection leads to voltage distortion at the end user side. In this paper a general voltage calculation algorithm is presented. This algorithm allows to calculate the phase voltages in the time-domain also when nonlinear devices are connected to the grid, i.e. under distorted regime. This is very useful for Power Quality issues.