ISEP – DEE – Comunicações em eventos científicos
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Percorrer ISEP – DEE – Comunicações em eventos científicos por Domínios Científicos e Tecnológicos (FOS) "Engenharia e Tecnologia::Engenharia Eletrotécnica, Eletrónica e Informática"
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- Influence of Solution Coding on Solving the Unit Commitment Problem with MetaheuristicsPublication . Viana, Ana; Sousa, Jorge P.; Matos, Manuel A.[Introduction excerpt] In Power Systems Engineering, as well as in many other areas of Electrical Engineering, optimising the usage of resources, subject to several constraints, is extremely important and usually difficult, due to specific technical, economical, or other particular aspects of the problem. The unit commitment problem is an important scheduling problem in planning the operation of power generators, and it is a good example of the interest devoted by the Power Engineering sector, to this area of research. It is the on/off decision problem of selecting the power generating units to be in service within a given planning horizon (from 1 day to 2 weeks, generally split in periods of 1 hour) and for how long. The committed units must satisfy the forecasted system load and reserve requirements, at minimum operating cost, subject to a large set of other system, technological and environmental constraints. Due to important start-up and shut-down costs, the problem is in general very hard to solve, as it is not possible to perform a separate optimization for each time interval. Furthermore, given that the operating costs depend on the load assigned to each generator, the problem of committing units over the planning horizon is directly connected to the additional problem of (roughly) assigning the load demand to the on-line units (“pre-dispatch” problem). The final, actual assignment is done later, for a much shorter period (usually from 15 to 60 minutes).
- Market power detection — simultaneous interchange capability evaluation under transmission congestionPublication . Gonçalves, Manuel João D.; Vale, Zita; Ramos, Carlos; Vale, ZitaElectric power market is under a rapid changing process world-wide. This new perspective, has given rise to competition with the goal of price fall and market domination. In general, market power is the ability of a particular seller or group of sellers to maintain prices profitably above competition levels for a significant period of time. The paper deals with transaction power tracing in the transmission system in order to evaluate simultaneous interchange capability under forced congestion effects. A method for detection of sellers combined strategies actions is proposed and impact on market distribution is evaluated.
- Optimal contracts allocation using mean variance optimization methodPublication . Azevedo, Filipe; Vale, Zita; Ramos, Carlos; Vale, ZitaThe process of restructuration and liberalization of power systems are a constant all over the world. However, those processes, due to the specific characteristics of the “product” electricity, create uncertainty and new risks that did not exist when power systems were vertically integrated. Those changes origin the necessity of tools that allow the participants of the electricity markets to practice the hedge against the volatility of the System Marginal Price. In that sense, we present in this paper a decision-support application, based on a Mean Variance Optimization Method trying to give a response to the necessities of the electricity markets participants. The results show that the proposed method can be useful to producers and also to others participants of electricity markets like Brokers and Load Serving Entities (LSE).
- A wholesale electricity market simulation toolPublication . Nogueira, Teresa; Vale, Zita; Vale, António; Ramos, Carlos; Vale, ZitaSeveral years have passed since the first efforts to restructure the electricity sector. Today many countries have already introduced electricity restructuring reform laws, a process commonly referred as deregulation. The arguments for deregulation include expected increased competition, new system efficiency, lower average costs to consumers and the promise of future improvement as markets grow in size and sophistication. The restructuring process has gone beyond the point of no return. In the European Union there are clear directives that impose the member states deadlines to implement competitive markets. Such is the case of Portugal and Spain, whose governments have decided to establish an Iberian electricity market. This paper presents a simulation prototype of a competitive wholesale daily market, including pool and bilateral transactions, inspired on the system that has been successfully performing in Spain and is about to prevail in the recently established MIBEL. The simulator provides users a means to obtain a deeper knowledge and awareness of a competitive electricity market.