Comparison Between Ring and Radial Configurations of the University of Trieste Campus MV Distribution Grid

Distribution systems are being pushed towards smarter architectures, management strategies, and controls. To develop new platforms and algorithms for distribution systems management, the University of Trieste is using its medium voltage MW-scale ring distribution system as a demonstrator. In addition to the installation of a real-time monitoring system, power system studies and analyses are required. The paper presents and compares some results concerning the power system operation in both closed (normal operation) and open (post fault operation) configurations, where the latter are identified by means of a quantitative dependability analysis. In particular, the voltage profile, the currents, and the losses in the system are studied, evaluating the impact of faults capable of opening the ring

A Stability-Aimed PMS for Shipboard Zonal DC Microgrids: The C-HIL Tests on Real-Time Platform

In future vessels, high reliability and flexibility in loads supply will be the main drivers in the power system design. To these aims, the zonal DC distribution is the most promising technology, as it enables the suitable and safe transfer of onboard power. Conversely, the large exploitation of filtered DC converters opens challenges, such as system stability. As large bandwidth controls on converters can reduce the stability margin of DC grids, the centralized Power Management System (PMS) can be programmed to supervise the stability status. In this paper, the Weighted Bandwidth Method (WBM) is implemented to configure the PMS when unstable conditions are foreseen. The smart PMS can tune the control gains in order to constantly ensure the stable operation of power distribution, regardless the system configuration. The capability of the reconfiguration algorithm is verified by performing a C-HIL test on a real-time platform

The User Experience as a Demand Response Action in Large All Electric Ships

In the global warming context, the newest All Electric Ships are to be designed to pursue efficiency and system sustainability. As in land power grids, also in shipboard applications the Demand Response is an efficient approach to achieve these important goals. Indeed, it can ensure a considerable reduction in the real-time demand of onboard loads, thus helping in avoiding power unbalances and consequent black-outs. From the digital world, the User Experience (UX) is coming as innovative strategy to smartly train the Demand Response (DR) actions. By several mechanisms, like incentives or gamification, the UX can greatly support the Demand Response in limiting the power requests from onboard users. The paper is conceived to give a short recap on DR, while raising the curtain on new UX methodology

The digital twin of complex shipboard DC microgrids: The high‐performing synergy of compiled models and HIL platform in the dynamics emulation of zonal power electronic power distribution systems

Nowadays, resilience is a crucial attribute to be pursued in advanced shipboard DC microgrids. When the power distribution is zonal, the presence of autonomous-controlled converters guarantees both power use and resiliency improvement. The adoption of bidirectional controlled devices ensures power routing among generating units, storage, and loads. Moreover, zonal electrical distribution systems are effective in applying the optimization algorithms for green, safe, and high-performing ship operation. In zonal DC microgrids, real-time cooperation among controlled converters through properly set communication protocols enables the ship mission achievement. To this aim, functional tests are to be done on such complex power infrastructure. The digital twin approach provides the de-risking step before the onboard deployment for controlled systems and communication. A zonal DC shipboard microgrid is the case study to test the synergy between compiled models and power converters on two hardware in the loop platforms, then verified by experiment in this paper. The first platform exploits the Linux real time application interface on the average value models of converters. This solution is then compared with a platform that utilizes the Typhoon hardware in the loop environment, proposing a combination of average value models and detailed switching models for the real-time emulation of controlled grid

High-Performance Megawatt-Scale MVDC Zonal Electrical Distribution System Based on Power Electronics Open System Interfaces

Integrated Power and Energy Systems (IPESs) will play a critical role in supporting future complex electric ship operations. In particular, flexibility is required to exploit shipboard energy sources and storages for multiple ship functions, supporting a highly dynamic electrical power use. To this aim, the Medium Voltage DC (MVDC) electrical power distribution has been conceived to provide requested power flexibility, along with other expected advantages in terms of functional integration and ship design. For complex and high-performance ship power systems, the Zonal Electrical Distribution System (ZEDS) concept has been proposed to maximize MVDC capabilities even under extremely demanding operational conditions. This paper presents a megawatt-scale test facility of a MVDC ZEDS developed and built in Trieste, Italy, based on power electronics open system interfaces. The demonstrator is described in its power and control design architectures and capabilities. In particular, a successful MW-scale test is presented, to show ZEDS capability in supporting large and fast load variations, while maintaining acceptable MVDC voltage tolerances

MIMO Control Architectures for Secondary Voltage Regulation in Electrically Coupled Transmission Grids: Design and Dynamic Performance

The progressive shift towards renewable energy sources in electric power production requires a revolution in transmission system control. In the latter, progressive reduction of high-power conventional power plants in favor of small distributed ones based on renewable energies (which present different dynamic performance), as well as the integration of new elements (regulating HVDC links, STATCOMs, etc.), makes the present transmission system structure and behavior significantly different compared to those taken as bases for the design of voltage control systems. Moreover, limitations due to technology obsolescence of the existing architecture and the greatly increased capabilities of modern Phase Measurement Units (PMU) contribute to requiring a revision of the voltage control architecture, which should also provide robustness to parameter variation and be adaptive in nature. To this end, in this work the applicability of different multiple input multiple output control methods to the transmission system secondary voltage regulation is investigated. Specifically, the Decoupling control method and the Linear Quadratic Regulator with Integral action control method are applied to the secondary voltage regulation of the Italian transmission system. Three different control system architectures, resulting from the application of these methods to the peculiarities of Italian transmission system voltage control architecture, are proposed in the paper. Their dynamic performance is tested on the model of a portion of the Italian transmission network in different scenarios, and compared with current Italian voltage control. The results suggest one of the proposed architectures as a promising solution to address the power system's evolution

The Coordinated Power Control of Flexible DC Microgrids in Sustainably Optimized Yacht Marinas

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

A coordinated voltage and reactive power control architecture for large PV 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

A Real-time Device for Smart Excitation Control Systems

This work presents a Smart Excitation Control System (ECS) for synchronous generators, implemented using a Real Time Operating System (RTOS), running on General Purpose Processors (GPPs). The Smart ECS is endowed with communications capability in order to operate as an Intelligent Electronic Device (IED) and can be regarded as a useful block for building future smart grids