Antoni Sudria-Andreu

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.

Operation of a Utility Connected Microgrid Using an IEC 61850-Based Multi-Level Management System

This paper presents a management system for a utility connected low-voltage microgrid composed of three nodes: a wind turbine, a battery and a variable load. These nodes are not commercial equipment but emulators. Each unit is composed of two identical voltage sources in back-to-back configuration. The microgrid is managed by a three-layered hierarchical automation system: the RMU layer, the iNode layer and the iSocket layer. The automation system permits two possible control modes: a centralized mode and a distributed mode. It has been developed an active and reactive power control that can be used for both management modes. Communications among the iNode and the iSockets are according to IEC 61850 standard. To implement IEC 61850 it has been used MMS-EASE Lite solution from SISCO, Inc. A commercial IEC 61850 SCADA has also been used.

Centralized and Distributed Active and Reactive Power Control of a Utility Connected Microgrid Using IEC61850

This paper describes the control algorithm of a utility connected microgrid, based on independent control of active and reactive power and operating in centralized and distributed operation mode. The microgrid is composed of several (three in the experimental tests conducted) configurable units, including generation, storage, and load units. These units are interfaced with the microgrid through a voltage source converter and are controlled by the nodes of the communication system by means of IEC 61850. The proposed control strategy is validated by simulation in MATLAB/Simulink and with experimental tests.

Modeling and Validation of DFIG 3-MW Wind Turbine Using Field Test Data of Balanced and Unbalanced Voltage Sags

A complete model of a doubly fed induction generator-based wind turbine generation system and its control scheme are developed. All components such as converters, dc-link, protections, and grid are modeled. Control techniques for torque, reactive power, and dc-link voltage are analyzed for balanced and unbalanced faults ride-through performance. Simulation results are validated and compared with field test measurements of an operational 3-MW wind turbine. Balanced and unbalanced voltage sags have been provoked and the data required by the grid codes to perform a validation process have been sampled by means of a data acquisition system. A comparison between field test data and simulation results is done and the variables used to validate the model are plotted showing their evolution along the voltage dip and after the fault clearance. The results are validated according to Spanish and German grid codes.

Experience on the implementation of a microgrid project in Barcelona

This paper deals with the implementation of a operating microgrid based on current real and emulated energy resources which permits the experimentation of various scenarios. This microgrid is able to adapt to different sorts of energy sources, loads and storage devices, and to critical situations that, with testing and emulation, can improve performances. The microgrid is implemented with real time data acquisition systems, communications (such as IEC 61850), and intelligent electronics peripheral equipment. Block diagrams, showing implementation using power electronics along with corresponding results, are shown for better understanding. Implementation and experimentation with the microgrid under investigation will improve future research on microgrid and smartgrid projects.

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.

Flexible manufacturing cell SCADA system for educational purposes

This article deals with the development of a Supervisory Control and Data Acquisition SCADA system to be used in a flexible manufacturing cell for educational purposes in different automation engineering fields (SCADA development, PLC programming and industrial communications). When dealing with industrial communications or PLC programming the SCADA is employed as a supervision tool. In the other hand, when teaching SCADA systems the application will be developed by the students and the SCADA presented in this article is employed as a model. The application communicates through Internet with four controllers, by means of an OPC server, visualizes comprehensive information about the elements of the cell, includes the video streaming of an IP camera, and features traceability and report generation capabilities.

Design, management and comissioning of a utility connected microgrid based on IEC 61850

This paper presents an approach to microgrid automation. The microgrid is composed of three different nodes connected to the public electric grid, which are hardware emulated with back-to-back converters. The microgrid is a flexible and weather independent test bed for testing different control algorithms. The intelligence of the automation system is split in three hierarchical layers: the RMU layer, the iNode layer and the iSocket layer. Communications among iNode and iSockets are according IEC 61850 standard. The aims of the project is to comission a set of technologies and acquire experience in microgrid automation, IEC 61850 communications and power control algorithms in DER systems.

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.

Control of a utility connected microgrid

This paper describes the control algorithm of a utility connected microgrid, based on independent control of active and reactive power (PQ control) and working in centralized operation mode. The microgrid under investigation is composed of three configurable units: a generation unit, a storage unit and a load. These units are interfaced with the microgrid through a Voltage Source Converter (VSC) and are controlled by the nodes of the communication system by means of IEC 61850. A set of tests have been conducted to evaluate the microgrid behavior.