An overview of grid-edge control with the digital transformation

Distribution networks are evolving to become more responsive with increasing integration of distributed energy resources (DERs) and digital transformation at the grid edges. This evolution imposes many challenges to the operation of the network, which then calls for new control and operation paradigms. Among others, a so-called grid-edge control is emerging to harmonise the coexistence of the grid control system and DER’s autonomous control. This paper provides a comprehensive overview of the grid-edge control with various control architectures, layers, and strategies. The challenges and opportunities for such an approach at the grid edge with the integration of DERs and digital transformation are summarised. The potential solutions to support the network operation by using the inherent controllability of DER and the availability of the digital transformation at the grid edges are discussed

PV plants performance analysis under mutable operating condition

This paper investigates the performances of PV plant installed in Southern Italy under mutable environmental conditions. This analysis has been performed on a measurement campaign, demonstrating how the performances of the PV system are influenced by the variability of solar irradiance. In fact, the more the irradiance level is high, the more will be the corresponding joule and thermal losses affecting the whole system. This evidence demonstrates the inadequacy of evaluation methods requiring a single instantaneous experimental verification of the minimum efficiency level used, for instance, for functional testing of photovoltaic systems

Multiarea Voltage Controller for Active Distribution Networks

The aim of this paper was to develop a multi-area decentralized controller for improving the voltage profile of large active distribution networks. Voltages at control buses of each area are kept as close as possible to their reference values by managing the reactive power of distributed generators within the same areas. Moreover, in order to avoid exchanging a considerable amount of data on more or less large portions of the network, the proposed methodology adopted an equivalent reduced network for each area. This equivalent network model is seen at control buses and nodes where distributed generation units are connected. With this simplification, each area controller will have to evaluate simultaneously, the unknown parameters of the reduced network and the optimal control laws for the voltage profile optimization of its control area. To comply with this exigency, a multi-objective optimization problem was formulated. The solution of this problem formulation was found by adopting an algorithm operating in the continuous time domain. Test results are provided on a 49-bus distribution network, demonstrating the effectiveness of the developed methodology

Wind Turbine Emulator for experimental microgrids

This paper presents the “hardware in the loop” wind turbine emulator installed at the PrInCE Lab microgrid of the Polytechnic University of Bari. The emulator consists of a four-quadrant 60-kVA AC/AC converter that behaves as a controlled current source for the microgrid. The control of the power converter is performed by a local microcontroller, which enables the emulation of different kinds of horizontal as well as vertical axis wind turbines. The emulator includes also an HMI software that allows the user to directly interact with the emulator, providing him the ability to choose the wind turbine model and wind speed to adopt for testing purpose

Case studies of microgrids systems

Microgrids (MGs) are becoming more attractive due to their ability to reduce energy costs for customers, allow the full exploitation of renewable energy sources and increase security, reliability and resiliency of the power distribution system. Moreover, the integration of MGs into power systems will alleviate the consequences of sudden grid outages on the end users and provide higher power security to critical loads. In addition, thanks to their ability to produce energy close to the consumption points, MGs offer a possible solution for reliable energy supply into the areas where the extension of power grids is considered technically and economically unfeasible. Nonetheless, their practical implementation into actual distribution networks is still hindered by several technical and economic issues. This chapter aims to show, by using several Case Studies of MGs, the value of each MG system in providing energy efficiency, ancillary services, demand response and electricity bill reduction

Microgrid architectures

This chapter presents a general description of microgrids (MGs), illustrating basic characteristics and structures of MGs with the objective of providing general background information on MGs that will help one to better understand the best promising structure and architecture in designing such systems. At present, AC MGs are still the main arrangement of MGs, even if they involve some drawbacks such as the need for synchronization of DG units, the circulation of reactive power and electromagnetic compatibility problems due to the intensive use of AC/direct current (DC) converters. Recently, DC MGs are emerging as a possible solution to avoid the aforementioned problems for a few isolated DC devices that must be connected into ex-novo networks. Although DC-powered components for residential and industrial applications are going to be more and more developed, the vast majority of existing devices currently in use in every area are fed in AC

An overview of grid-edge control with the digital transformation

Distribution networks are evolving to become more responsive with increasing integration of distributed energy resources (DERs) and digital transformation at the grid edges. This evolution imposes many challenges to the operation of the network, which then calls for new control and operation paradigms. Among others, a so-called grid-edge control is emerging to harmonise the coexistence of the grid control system and DER’s autonomous control. This paper provides a comprehensive overview of the grid-edge control with various control architectures, layers, and strategies. The challenges and opportunities for such an approach at the grid edge with the integration of DERs and digital transformation are summarised. The potential solutions to support the network operation by using the inherent controllability of DER and the availability of the digital transformation at the grid edges are discussed