DCOPF Contingency Analysis Including Phase Shifting Transformers

This work deals with a new formulation for the Direct Current Optimal Power Flow (DCOPF) including the corrective actions related to the phase shifting transformers. The formulation is based on the outage of generators and/or branches modelled as fictitious injections of active power. The inclusion of the sensitivities of the phase shifting transformer with respect to the injected powers is one of the novelties of this paper. By including the fictitious injections in the optimization problem, the injections are adjusted to the post-contingency state as a consequence of the corrective actions carried out by the DCOPF to bring the system back to its normal state. Consequently, when the analysis of contingencies is performed, the classical topological analysis and the subsequent analyses are avoided with this approach. The DCOPF includes as corrective control variables the rescheduling of active power generations, phase shifting transformers and, if required, permitted load shedding. The IEEE-RTS of 24 buses is used as benchmark network to assess the properties of the proposed approach.Spanish Ministry of Science and Innovation and Cooperation (Spain) ENE2011-24137Spanish Ministry of Science and Innovation and Cooperation (Spain) ENE2011-27984Junta de Andalucía PO11-TEP741

A new DC corrective OPF based on generator and branch outages modelled as fictitious nodal injections

This work deals with a new formulation for the direct current corrective optimal power flow. The formulation is based on the outage of generators and/or branches modelled as fictitious injections of active power. By including that fictitious injections in the optimization problem, the injections are adjusted to the post-contingency state as a consequence of the corrective actions carried out to bring the system back to its normal state. So, when the analysis of contingencies is performed, the classical topological analysis and the subsequent analyses are avoided with this approach. This new formulation uses the sensitivity matrix between branch power flows and powers injected in a power system. An important feature of this matrix is to remain constant during the Contingency Analysis performed for the generation-load scenario (base case) of each period of time to be analysed. The approach proposed is illustrated in the IEEE-RTS of 24buses. The results obtained in this distribution network demonstrate that the proposed methodology can assess the impact of contingencies with an acceptable accuracy and a short computation time.Spanish Ministry of Science and Innovation grant ENE2011-27984Spanish Ministry of Science and Innovation grant ENE2010-18867Junta de Andalucía TEP-517

Sensitivity-based external equivalent for reliability assessment of subtransmission & distribution systems

It is well known that topology changes in a power system strongly influences the results of reliability assessment studies. Besides, it is obvious that the topology of an external system also affect the reliability of the internal system through changes on the power flows within the rest of the system, and hence, through changes on the tie lines. In order to properly model the interconnection between the internal network and the rest of the system, an adaptive external equivalent model, obtained from the sensitivity matrix between tie-linepower flows and injectedpowers, is proposed for reliability assessment studies. The proposed technique has been applied to the IEEERTS, and test results show that the proposed methodology is suitable both for planning studies and for 24-hour-ahead reliability assessment studies.Spanish Ministry of Science and Innovation ENE2010-18867Spanish Ministry of Science and Innovation ENE 2007-63306Spanish Ministry of Science and Innovation ENE 2007-66072Ministry of Foreign Affairs and Cooperation A/030124/10Junta de Andalucía TEP-517

A Hybrid Procedure Including Subtransmission Systems and Substations for Reliability Assessment

A new procedure focused on reliability analysis of subtransmission systems supported by the state enumeration technique is presented. This new methodology is conducted in three stages. First, a classical state enumeration reliability assessment is performed for the branch-node model of a subtransmission system, assuming that substations are perfectly reliable. Second, a detailed model of the subtransmission system is considered and the reliability of each substation is assessed by considering them in a “one-by-one” process, supposing perfect operation for the branch-node model. Finally, the reliability indices calculated in the first and second stages are analytically combined to obtain the reliability indices for the subtransmission system (system reliability indices) and for the load nodes of the distribution system (load-node reliability indices). Test results show that the proposed methodology is suitable for both planning studies and 24 hours-ahead security assessment.Spanish Ministry of Science and Innovation grant ENE2010-18867Ministry of Foreign Affairs and Cooperation grant A/030124/10Junta de Andalucía TEP-517

A new technique for short-term reliability assessment of transmission and distribution networks

This paper proposes a new methodology for shortterm (24 hours) reliability assessment of transmission and distribution networks, including detailed substations models. Substations are first considered as single electrical nodes to evaluate the reliability of delivery nodes. If nodes (substations) with a high LOLP (Loss of Load Probability) are identified in this preliminary analysis, the critical substations are modeled in detail to obtain the corresponding reliability indices with a higher accuracy, especially the indices corresponding to delivery points (feeders). The proposed methodology includes a topological analysis module similar to the topological processor used in State Estimation, a DC Load Flow, a DC-OPF module to compute remedial actions, and a reliability evaluation module based on state enumeration. The proposed approach is flexible and easy to implement, and special efforts have been made to reduce the computational requirements and to present the results in a way appropriate to both operators and planning engineers.Ministerio de Ciencia y Tecnología (España) ENE 2004-0334

An Interactive Educational Tool for the Teaching of Manoeuvres in Electrical Substations

The philosophy of safety at work is one of the bases for the operation of electrical installations, with particular relevance in the manoeuvres in electrical substations. The curriculum for Electrical Engineering students should include such knowledge. This article presents an educational tool currently in use, which has demonstrated its full effectiveness in achieving the implementation of safe working methods in the planning and execution of manoeuvres in electrical substations.Ministerio de Educación y Ciencia (Spain) ENE2007-63306Ministerio de Educación y Ciencia (Spain) ENE2007-66072Ministerio de Ciencia e Innovación (Spain) ENE2010-1886

Laboratory work in teaching basic three-phase electrical circuits

This paper describes a laboratory-based teaching proposal for the understanding of three-phase circuits at the undergraduate level of engineering degrees. The practical content of the proposed activities is oriented towards easing the students’ understanding of the main concepts involved in three-phase circuits. The subject of three-phase circuits forms the basis for an elementary undergraduate course on circuit analysis. This work proposes simple and didactic laboratory lessons for the long-term understanding of many concepts involved in three-phase circuits which are often covered by only theory or simulation. The practical teaching proposed has been successfully implemented in the Industrial School of Engineering of the University of Seville and can easily be included in the laboratory curriculum of other Engineering schools.Junta de Andalucía P06-TEP-01882Ministerio de Ciencia y Tecnología (Spain) ENE2007-6299

Teaching reliability analysis of HV/MV substations and distribution feeders using educational software

In this paper, educational software for the reliability assessment of high/medium-voltage (HV/MV) substations and distribution feeders is presented. It is a useful tool for learning the utility of reliability indices of the HV/MV substations and their distribution feeders, and their influence on the electrical power system operation. By means of an interactive graphical interface, multiple configurations of HV/MV substation layouts can be selected. The Monte Carlo method and the equipment outages have been used to calculate the expected reliability performance of substations and primary distribution feeders. The proposed educational tool has been evaluated to measure students’ satisfaction, and questionnaire and results of this evaluation are presented and discussed.Ministerio de Educación y Ciencia (España) ENE2007-63306Ministerio de Educación y Ciencia (Spain) ENE2007-66072Ministerio de Educación y Ciencia (Spain) ENE2010-1886

Análisis de un sistema híbrido solar eólico para suministro de energía eléctrica

El panorama socioeconómico actual ha propiciado un gran auge en el uso de energías renovables. El importante crecimiento de estas energías, también se debe en gran medida a la preocupación social por los impactos medioambientales de las denominadas energías no renovables. Hay casos en los que se tiene que acometer el suministro de energía eléctrica a instalaciones donde, o bien no existe una línea eléctrica cercana, o bien su implantación supone un coste elevado. Bajo estas circunstancias, es especialmente adecuado el uso de energías que puedan obtenerse directamente de la naturaleza y en el mismo lugar donde se van a consumir. En este ámbito, a continuación se describe una instalación que usa la energía del viento y la energía del sol como fuentes primarias de producción de energía eléctric