Roberto Villafafila-Robles

Response of Fixed Speed Wind Turbines to System Frequency Disturbances

This paper analyzes the impact of system frequency variations on the steady-state operation point of fixed speed induction generators used in wind turbine generation systems (WTGS). An analytic method to predict the values of angular speed, torque and current during and after a frequency disturbance is presented. The proposed method as well permits to establish the operation limits in order to keep the WTGS connected during frequency variations and therefore to adjust protection relay settings.

A Remote Laboratory Platform for Electrical Drive Control Using Programmable Logic Controllers

Many teaching institutions worldwide are working on distance learning applications. In this field, remote laboratories are enabling intensive use of university facilities, while aiding the work of professors and students. The present paper introduces a platform designed to be used in industrial automation practical work. The platform is communicable through the Internet, includes programmable logic controllers that can be programmed with the open software CoDeSys, and has various sensors and actuators used in industrial installations. The various experimental stations of the platform, and the proposed laboratory exercises are described. The results of having used the platform with students are discussed.

Electrical vehicles: State of art and issues for their connection to the network

The recent awareness about fossil fuels and the environment has arisen more sustainable alternatives regarding means of transport. The first alternative of green transport has been hybrid vehicles. This kind of vehicles reduces significantly the CO2 emission but not totally. Nowadays, the current trend is the utilization of a unique motor for vehicle. i.e. an electrical motor. It seems that the electric vehicles (EV) will become the cars of the future. Moreover, one kind of such vehicles, the plug-in electric vehicles (PHEV), will not only charge their batteries, but PHEV will also be able to inject power to the network when required. This fact suggests that EV penetration will affect current power system performance. Then, it is necessary to study some scenarios of penetration of such vehicles into the electrical network in order to maintain security and quality of power supply.

Deterministic and probabilistic assessment of the impact of the electrical vehicles on the power grid

This paper analyzes the impact of charging of EVs (Electrical Vehicles) on a MV power grid. In order to simulate the behavior of the EV charging a battery model has been used to model the EVs charging curve. As the way how EV is charged from the grid affects critically to the voltage levels and to the saturation of the lines, two modalities of charging are presented: not-controlled charging and controlled charging. Finally, the simulations have been performed from two points of view: deterministic analysis and probabilistic analysis.

Modeling and validation of a flywheel energy storage lab-setup

This work deals with the modeling, control and experimental validation of a flywheel test bench which is part of IRECs lab-scale microgrid. The storage device has been designed as a proof of concept. It is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous Machine. The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also regulate the reactive power at the point of common coupling with the external grid. Vector control techniques are used for designing the converter controllers: a field oriented vector control algorithm is implemented for governing the servomotor while the instantaneous power theory-based algorithm is used to manage the active and reactive currents flowing from the grid side converter. The control implementation in the experimental setup has been carried out by means of programming Digital Signal Processors (DSPs). The modeling and control system design has been validated after executing several experiments.

Power quality education using a remote monitoring laboratory

The increasing need of qualified engineers in the field of power quality in industry is pushing teaching methods to both project based learning and real applications. In order to interpret power quality phenomena, students may experiment and learn from real applications because experience is needed in order to be an expert in this field. The present paper describes how power quality education can use remote laboratories in order to create practice near laboratory tutorials for power quality monitoring. The remote laboratory is used by graduate students in regular courses and by engineers for life-long learning.

Electric vehicles in power systems with distributed generation: Vehicle to Microgrid (V2M) project

The integration of electric vehicles into distribution networks will require intelligent systems for managing the charging points and the impact on the grid. Electric vehicles represent an opportunity to manage the power demand allowing shifting the electric load to off-peak periods and to store the excess of generation from renewable generators. In addition, the electric vehicles could be used to improve the reliability and power quality if vehicle to grid (V2G) is deployed. The Vehicle to Microgrid (V2M), an Endesa Novare Award, consists on evaluating the impact of electric vehicles into the network and proposing solutions to deal with the challenges that electric vehicles introduce. The results will be validated in a demonstration plant that is a microgrid placed at IREC.

Short-term voltage stability of fixed-speed wind turbines: Comparison of single and double cage

This paper studies the short-term grid voltage stability of double cage induction generators in fixed speed wind turbines. The performed analysis shows that for voltage stability studies of fixed speed wind turbines with induction generators (either single or double cage), the mechanical rotor turbine model is preferable as a detailed aerodynamic model. Simulations of the suggested modeling approaches are presented, and the influence of detailed rotor torque modeling is analyzed. The double cage induction generators show better short-term grid voltage stability performance.

Protection system remote laboratory

Remote laboratories are a learning tool that allows carrying out tutorials without being physically present in the laboratory facilities. Such sort of platforms can be useful to complement students learning with some practical activities. Timetables flexibility is the main advantage of remote laboratories for both students and teachers, since these laboratories are in operation 24 hours per day without requiring any supervisory assistance. The protection and distribution power systems have recently changed by the effect of the new information and communication technologies. As these changes have been carried out in such a short period of time, professionals with knowledge in these topics are required. Additionally it would be needed to include distribution automation concepts in current subjects and finally create didactic material to be used in practical sessions. This paper presents an e-laboratory of electrical protections that emulates the structure and conditions of a distribution grid. This laboratory is used to perform practical activities in degree and master subjects and professional courses dealing with electrical protections, automation and communications.

Modeling, Control and Experimental Validation of a Flywheel-Based Energy Storage Device

Abstract This work deals with the modeling, control and experimental validation of a flywheel-based energy storage device. The system is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous Machine (PMSM). The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also regulate the reactive power at the point of common coupling with the external grid. Vector control techniques are used for designing the converter controllers: a field oriented vector control algorithm is implemented for governing the servomotor while an instantaneous power theory-based algorithm is used to manage the active and reactive currents flowing from the grid side converter. The control implementation in the experimental setup has been carried out by means of programming Digital Signal Processors (DSP’s). The modeling and control system design has been validated after executing several experiments. Other characteristics such as the torque losses of the system as well as the system performance concerning energy rating, power rating and energy efficiency characteristics are determined experimentally.