Today's electricity paradigm requires that the notion of active distribution systems be introduced at both undergraduate and graduate curricula. This involves not only the customary theoretical foundations but also a suitable power engineering laboratory, where flexible enough and affordable resources allow students and researchers to carry out hands-on experiments reinforcing the concepts explained in the classroom. This paper describes the smart grid laboratory of the Power Engineering Group at the University of Seville, composed of a scaled-down distribution system, along with the required control and monitoring equipment, designed to help its users easily grasp the major influence that distributed generation and storage devices exert in the operation of medium-voltage distribution systems.

The smart-grid era is characterized by a progressive penetration of distributed energy resources into the power systems. To ensure the safe operation of the system, it is necessary to evaluate the interactions that those devices and their associated control algorithms have between themselves and the pre-existing network. In this regard, Hardware-in-the-Loop (HIL) testing approaches are a necessary step before integrating new devices into the actual network. However, HIL is a device-oriented testing approach with some limitations, particularly considering the possible impact that the device under test may have in the power system. This paper proposes the Power System Hardware-in-the-Loop (PSHIL) concept, which widens the focus from a device- to a system-oriented testing approach. Under this perspective, it is possible to evaluate holistically the impact of a given technology over the power system, considering all of its power and control components. This paper describes in detail the PSHIL architecture and its main hardware and software components. Three application examples, using the infrastructure available in the electrical engineering laboratory of the University of Sevilla, are included, remarking the new possibilities and benefits of using PSHIL with respect to previous approaches.

Ancillary services are all services required by the transmission (TSO) or distribution system operator (DSO) to maintain the integrity and stability of the transmission or distribution system as well as the power quality. Ancillary services that can be provided by a microgrid in grid-connected operation are frequency control support, voltage control support, congestion management, reduction of grid losses, and improvement of power quality. This paper presents the optimization problems used in the 3DMicroGrid project to determine the set-points of the different resources present in the microgrid to provide ancillary services to the power system in grid-connected operation: frequency control, voltage control and load curtailment. Results of the optimization of the pilot microgrid used in 3DMicroGrid are presented.