The paper proposes an optimal management strategy for a system composed by a battery and a photovoltaic power plant. This integrated system is called to deliver the photovoltaic power and to simultaneously provide droop-based primary frequency regulation to the main grid. The battery state-of-energy is controlled by power offset signals, which are determined using photovoltaic energy generation forecasts and predictions of the energy required to operate frequency regulation. A two level control architecture is developed. A day-ahead planning algorithm schedules the energy profile which is traded at the day-ahead market and defines the primary control reserve that the integrated system is able to provide in the considered day. During the day operations, a second level algorithm corrects the dispatched plan using updated information, in order to guarantee a continuous and reliable service. Both control algorithms take into account the uncertainties of the photovoltaic generation and of the frequency dynamics using stochastic optimization.
7 April 2022 in IEEE Transactions on Power Systems
This paper introduces an algorithm able to detect and localize the occurrence of a fault in an Active Distribution Network, using the measurements collected by Phasor Measurement Units (PMUs). First, a basic algorithm that works under the assumption that all grid buses are equipped with a PMU is designed. Then, formal observability conditions that allow detection and localization with a reduced number of PMUs are provided. Based on these conditions, the algorithm is extended to perform correctly when not all network buses are monitored. Moreover, an Optimal Positioning Algorithm, always based on the observability conditions, is designed. This algorithm allows the user to customize the fault localization resolution. The approach is validated through simulations carried out on a benchmark active distribution network.
1 September 2020 in Sustainable Energy, Grids and Networks
Recent and strict regulations in the maritime sector regarding exhaust gas emissions has led to an evolution of shipboard systems with a progressive increase of complexity, from the early utilization of electric propulsion to the realization of an integrated shipboard power system organized as a microgrid. Therefore, novel approaches, such as the model-based design, start to be experimented by industries to obtain multiphysics models able to study the impact of different designing solutions. In this context, this paper illustrates in detail the development of a multiphysics simulation framework, able to mimic the behaviour of a DC electric ship equipped with electric propulsion, rotating generators and battery energy storage systems. The simulation platform has been realized within the retrofitting project of a Ro-Ro Pax vessel, to size components and to validate control strategies before the system commissioning. It has been implemented on the Opal-RT simulator, as the core component of the future research infrastructure of the University of Genoa, which will include power converters, storage systems, and a ship bridge simulator. The proposed model includes the propulsion plant, characterized by propellers and ship dynamics, and the entire shipboard power system. Each component has been detailed together with its own regulators, such as the automatic voltage regulator of synchronous generators, the torque control of permanent magnet synchronous motors and the current control loop of power converters. The paper illustrates also details concerning the practical deployment of the proposed models within the real-time simulator, in order to share the computational effort among the available processor cores.
The integration of fuel cell technology in shipboard is essential for real fuel and pollution reduction in the marine sector. This integration can be pushed in the adoption of a dc shipboard power system (SPS). One of the impediments to this integration is the necessity to couple fuel cells (FCs) and battery energy storage systems (BESSs) and control them with a proper power management system (PMS), in order to sustain high load variations due to electric propulsion. In the literature, all these aspects are dealt independently and mostly assuming ideal conditions. The proposed control strategies are derived from the droop and secondary frequency regulation of the ac power system. This paper starts with a brief description on the characteristics of dc SPS along with fuel cell and battery modeling. Subsequently, this paper describes the proposed control strategy. Finally, this paper shows the behavior and principle of the proposed integration and analyzes the performance on a real measurement test case of a ferry. This paper is concluded by identifying the future research for the development of a PMS control strategy for critical marine missions.