Power management systems. A fast, efficient and smart power management system is the key component of Smart Grids. It consists typically by a central (master) power management system, a number of smart meters and sensors, a smart communication network, control and automation systems and a supervision system. Such a configuration is shown in Fig. 1. Active participation by consumers. Electrical appliances are no longer merely passive devices but active participants in the system’s infrastructure. This means that the electrical loads communicate with the control system, they are variable in a smart way and ideal complements to the renewable sources engaged, which are variable in energy production. Smart appliances can also contribute to peak power haircuts. “Self-healing” from power disturbance events. The rapid detection, analysis, response and restoration of the grid’s operation in cases of any power system disturbances including physical destructions and cyber attacks are critical functions of a smart grid. PQ/EMC and Reliability. A certain level of power quality and reliability is desirable in both land and naval power systems. A smart grid should assure this level of electromagnetic compatibility between the grid and the electrical equipment according to strict and applicable standards and requirements. Power converters. They are used as an interface between the electric power generation units and the grid. The most common types are the DC/AC, AC/DC/AC and AC/AC. Accommodation of renewable energy generation and storage units. Modern power systems have substantially larger contribution from low-carbon and renewable sources, which are characterized by intermittency of operation and a lack of ability to dispatch. The high penetration of such sources in an automation and control system is therefore a challenging issue as regards the maintenance of a balance between instantaneous supply and demand. In such cases, storage technologies and their control are crucial [5]. A typical configuration of a power network incorporating renewable and storage units for the electricity supply of a ship’s electrical loads is shown in Fig. 2.
Fig. 1 Typical configuration of the control, communication and power network of a smart grid
Obviously, the aforementioned are the most important common areas of research and development for land and ship power systems. There are also some research domains related with ship power systems and smart grids. These include “cold ironing”, shaft generator systems and electric energy saving devices (EESD’s). “Cold ironing” refers to a shore-side power supply connection of a ship with the ship's machinery shut-down and with the requirement that the port has the infrastructure and the green– energy (e.g. renewables) to support the effort [6]. Cold ironing and smart-grids can be combined successfully, if any deficiency problems in infrastructure aboard and ashore have been resolved. Specifically, instead of directly connecting the ships to the grid mains, efficient energy storage units