The operation of the hierarchy-based voltage regulation architecture of the Italian transmission system is being affected by the efforts to fight climate change. Energy production is becoming more distributed and converter-based, as a result of the increased use of renewable energy sources and the progressive shutdown of less-sustainable power plants (like coal-fired ones), which affects the controllability of the system. Therefore, the actual secondary voltage control, dedicated to maintaining the voltage of specific transmission system nodes at a given reference value, is becoming less effective. A coordinated Linear Quadratic Regulator with Integral action (LQRI) secondary voltage controller can be used to face such issue. However, issues must be solved to provide an implementation suitable for the Italian transmission system. Need of adaptivity, due to power system's operating points frequent modification, and a variable number of actuators, due to the reactive power resources' connection/disconnection, pose a significant challenge. The resulting frequent update in controller parameters’ leads to unwanted step variations in the control signals at each update, if not properly addressed. To solve such an issue, in this paper a bumpless control realization for an LQRI is proposed, demonstrating its effectiveness with a linear system model, and validating the results with a more detailed non-linear system model based on recursive power flow calculation.

Nowadays, the industrial world is undergoing a disruptive transformation towards more environmentally sustainable solutions. In the blue economy, this new approach is not only expressed in the domain of actual vessels, but also in the development of charging infrastructure, displaying a notable transition towards more eco-friendly solutions. The key focus lies in adopting flexible power systems capable of integrating renewable energy sources and storage technologies. Such systems play a crucial role in enabling a shift towards low-emission maritime transport. The emissions reduction goal extends beyond onboard shipboard distribution systems, encompassing also the design of supplying platforms and marinas. This study explores the implementation of a controlled DC microgrid tailored to efficient management of power flows within a yacht marina. Once having established the interfaces for the vessels at berth, the integration between the vessels, the onshore photovoltaic plant and the battery storage unit is made possible thanks to the coordinated management of multiple power converters. The overarching goal is to curtail reliance on external energy sources. Within this DC microgrid framework, a centralized controller assumes a pivotal role in orchestrating the power sources and loads. This coordinated management is essential to achieve sustainable operations, ultimately leading to the reduction of emissions from both ships and onshore power plants.

The increasing presence of nonprogrammable renewable energy sources (RES) forces towards the development of new methods for voltage control. In the case of centralized generation, the hierarchical regulation or secondary voltage regulation (SVR) is guaranteed by coordinated voltage and reactive power controls in transmission systems. This type of regulation loses effectiveness when the generation becomes distributed and based on small and medium sized generators. To overcome this problem, it is important that also distributed generators, typically based on RES, participate in the voltage regulation. By starting from the methodologies already applied, this work wants to present a new method for involving distributed generators in SVR. The novelty is given by the application of an existing methodology to the new configuration of electrical grids characterized by a relevant distributed generation. The aim is to control the distributed generators (DGs) as coordinated sources of reactive power for conveniently supporting the voltage regulation. In this paper, a real large photovoltaic (PV) plant is considered. The power plant is composed of several PV generators connected through a distribution network. With the algorithm proposed, the set of generators can be treated as a single traditional power plant that can participate in the hierarchical voltage regulation. The reactive power of each single generator is coordinated in a way similar to the SVR used in several national systems.

The most advanced DC shipboard power systems will be based on the wide deployment of controlled converters in a zonal distribution configuration. On one side the power electronics arrangement enables advantages for the onboard functioning (e.g. flexibility, redundancy and adaptability), on the other it can open worrying issues on DC system stability. When perturbing a negative-damped DC power grid, the incoming instability triggers a ship blackout as a consequence. To avoid this catastrophic eventuality, the Power Management System (PMS) is programmed for the smart real-time adaptation of converters bandwidths. The paper presents a Preventive-Resilient (P-R) bandwidths tuning to guarantee the stable functioning, even when assuming the (n-1) eventuality, so the unexpected disconnection of the more stabilizing load. This reconfiguration is an effective measure to constantly ensure a sufficient stability margin, even when low-bandwidth loads are offline. The capability of P-R algorithm is evaluated by a C-HIL test on a digital real-time platform. A Python code acts as a PMS in configuring the bandwidths on emulated converters via the Modbus communication protocol. The combination of a simplified stability assessment method with an optimization algorithm enables a fast bandwidth reconfiguration process without requiring excessive computational effort. These characteristics make the proposed approach suitable for integration into the shipboard Power Management System (PMS), providing central controllers with an online stability assessment and safe load management tool.

Distributed Generation is growing at important rates due to several reasons, including, in some countries, the strong penetration of renewable generating plants. Voltage rise is a considerable problem that prevents generators from injecting more active power into distribution networks. After a review of recently proposed mitigation techniques, a voltage rise mitigation technique is presented. The technique is based on a coordinated reactive power control of the distributed generators which takes into account the capability limits of the generators. It is suitable for utilization in distribution networks equipped with or without a dedicated communication infrastructure.