An approximation to the prediction of the summery emergence of "Ochlerotatus caspius" (Diptera: Culicidae) based on the relationship between degree-days accumulations and adult captures

Ochlerotatus caspius (Pallas) (Diptera, Culicidae) es el culícido más abundante durante el verano en las marismas de Huelva. Este estudio demuestra que la relación entre capturas de adultos, convertidas en probit, y la acumulación de temperatura o número de días-grado, convenientemente adaptada mediante a una transformación logarítmica, muestra ser signifi cativamente lineal para cada generación de este mosquito a lo largo de cada verano. Además, si se procesan todos los datos disponibles de todos los años considerados en el estudio se obtiene una alta correlación lineal y, en consecuencia, las ecuaciones resultantes poseen valor predictivo. Los resultados de la validación de los pronósticos que se extraen de las rectas de regresión log-probit, permiten que se puedan considerar estas rectas como una herramienta más de cara a aumentar la efi cacia de los programas de control integrado que se llevan a cabo en esta zona.Predicción de la emergencia estival de Ochlerotatus caspius (Diptera: Culicidae) basada en la relación entre la acumulación de días-grado y la captura de adultos. Ochlerotatus caspius (Pallas) (Diptera, Culicidae) es el culícido más abundante durante el verano en las marismas de Huelva. Este estudio demuestra que la relación entre capturas de adultos, convertidas en probit, y la acumulación de temperatura o número de días-grado, convenientemente adaptada mediante a una transformación logarítmica, muestra ser signifi cativamente lineal para cada generación de este mosquito a lo largo de cada verano. Además, si se procesan todos los datos disponibles de todos los años considerados en el estudio se obtiene una alta correlación lineal y, en consecuencia, las ecuaciones resultantes poseen valor predictivo. Los resultados de la validación de los pronósticos que se extraen de las rectas de regresión log-probit, permiten que se puedan considerar estas rectas como una herramienta más de cara a aumentar la efi cacia de los programas de control integrado que se llevan a cabo en esta zona

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

An Evolutionary Computational Approach for the Problem of Unit Commitment and Economic Dispatch in Microgrids under Several Operation Modes

In the last decades, new types of generation technologies have emerged and have been gradually integrated into the existing power systems, moving their classical architectures to distributed systems. Despite the positive features associated to this paradigm, new problems arise such as coordination and uncertainty. In this framework, microgrids constitute an effective solution to deal with the coordination and operation of these distributed energy resources. This paper proposes a Genetic Algorithm (GA) to address the combined problem of Unit Commitment (UC) and Economic Dispatch (ED). With this end, a model of a microgrid is introduced together with all the control variables and physical constraints. To optimally operate the microgrid, three operation modes are introduced. The first two attend to optimize economical and environmental factors, while the last operation mode considers the errors induced by the uncertainties in the demand forecasting. Therefore, it achieves a robust design that guarantees the power supply for different confidence levels. Finally, the algorithm was applied to an example scenario to illustrate its performance. The achieved simulation results demonstrate the validity of the proposed approach.Ministerio de Ciencia, Innovación y Universidades TEC2016-80242-PMinisterio de Economía y Competitividad PCIN-2015-043Universidad de Sevilla Programa propio de I+D+

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

A comparison of residual demand models for oligopolistic markets

15th Power Systems Computation Conference August 22-26, 2005 Liège, BelgiumIn many pool-based electricity markets two types of generating companies coexist, namely price-taking and leader companies. In this context, the optimal bidding of a leader company, and consequently the market clearing price, is mainly determined by its residual demand curve, which can be modeled in different ways. In this work, three different residual demand curves have been adopted to simulate the optimal strategy of an oligopolistic company. The influence of these models on the gap between the expected and actual market prices, as well as on the resulting leader company profit is analyzed.Ministerio de Ciencia y Tecnología DPI2001-2612Junta de Andalucía ACC-1021-TIC20

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