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

Design of Zonal Electrical Distribution Systems for Ships and Oil Platforms: Control Systems and Protections

Complex energy vessels such as large platforms or drillships require more efficient use of electrical power. As shipboard electrical systems become larger, problems and limits arise with the ac distribution architecture. Hybrid ac/dc onboard distribution systems are today available, which provide higher efficiency and redundancy. IEEE Std. 1662, 1709 and 1826 set technical rules and recommendations for the design of hybrid ac/dc shipboard electrical systems. Among these, zonal electrical distribution systems (ZEDS) are considered a next technological evolution, as they provide optimal power sharing (and energy storage) along with high reliability

Reactive Power Resources Management in a Voltage Regulation Architecture Based on LQRI Control

The Italian transmission system's voltage control is based on its subdivision into decoupled control areas, where a hierarchical regulation architecture is applied. However, the structure and the voltage regulation of the electrical power system are being significantly impacted by the actions being taken to limit climate change. The increase in renewable energy sources exploitation is leading to a more-distributed and converter-based energy production. In addition, the forthcoming coal-fired plants shut-off will force the shift from providing regulation capability with a small number of big power plants, towards using a big number of smaller resources. Thus, in the near future a decrease in the effectiveness of the present voltage control architecture is expected. To solve such issue, a new voltage control architecture is needed, involving the more-distributed and converter-based energy production systems, as well as no longer relying on physically decoupled control areas. Therefore, in this paper a coordinated LQRI secondary voltage control is presented, able to use each grid-available reactive power source as an actuator. Furthermore, a bumpless transfer technique is proposed to solve the problem of managing a varying number of actuators (due to the reactive power resources' connection and disconnection)

Study on the State Feedback Selection and Measurement for the Application of an LQRI Secondary Voltage Regulator to a Transmission System

The electrical power system is being significantly affected by the climate change mitigation actions. The power generation, originally centralized, is transitioning towards a more decentralized paradigm due to the coal-fired power plants shut off and the increase in renewable power. Issues in transmission system's voltage control may arise, if the voltage regulation architecture is not modified accordingly. To this aim, in this paper it is investigated the use of a Linear Quadratic Regulator with Integral action (LQRI) for the secondary voltage regulation, aimed at exploiting several reactive power sources as actuators. Being the LQR class of regulators requiring the system state to correctly operate, and being a transmission system a complex system, a critical investigation must be done. In particular, it is needed to identify the variables that are directly measured in a real system, determine if they can be useful for the LQRI state feedback, and finally study the effect of the different possible feedback selection on the regulation performance

An Application of Modular Design in the Refitting of a Hybrid-electric Propelled Training Ship

Nowadays specific ships are used to train students as sailors. As historical vessels are conveniently employed to this aim, the average age of these ships is usually high. In order to amortize operating and maintenance costs, the training ships\u2019 ownership (except for naval ones) is shared among multiple entities and schools. Moreover, generally these vessels are used in coastal navigation. The consequent operational profile imposes the need to rearrange the ship internal spaces according to the shipowner who will use it. Considering all these reasons, a modular design approach can be adopted in the refitting process, while reverse engineering techniques and integrated design tools should be used for the reconstruction when the original technical documentation is not available. In this context, hybrid-electric propulsion systems can be proposed as effective to enable the Zero Emission Mode, thus reducing the vessel\u2019s environmental impact during the training. By doing this, three goals are achieved to extend the ship operational life: ease of rearrangement of the internal spaces for different uses, reduction of operating/maintenance costs and eco-sustainability in coastal navigation. In this paper, after a description about modular design and hybrid electric technologies, the refitting project of the M/N \u201cUmberto d\u2019Ancona\u201d is discussed. The latter is the training ship of \u201cTomaso di Savoia Duke of Genoa\u201d, the nautical institute in Trieste, Italy