Details
Name
Mário Hélder GomesCluster
Power and EnergyRole
External Research CollaboratorSince
08th November 2006
Nationality
PortugalCentre
Power and Energy SystemsContacts
+351222094230
mario.h.gomes@inesctec.pt
2010
Authors
Mário Hélder Gomes; João Tomé Saraiva
Publication
EPSR - Electric Power Systems Research, vol.80, no.10, pp.1267-1276
Abstract
MicroGrids represent a new paradigm for the operation of distribution systems and there are several advantages as well as challenges regarding their development. One of the advantages is related with the participation of MicroGrid agents in electricity markets and in the provision of ancillary services. This paper describes two optimization models to allocate three ancillary services among MicroGrid agents – reactive power/voltage control, active loss balancing and demand interruption. These models assume that MicroGrid agents participate in the day ahead market sending their bids to the MicroGrid Central Controller, MGCC, that acts as an interface with the Market Operator. Once the Market Operator returns the economic dispatch of the Microgrid agents, the MGCC checks its technical feasibility (namely voltage magnitude and branch flow limits) and activates an adjustment market to change the initial schedule and to allocate these three ancillary services. One of the models has crisp nature considering that voltage and branch flow limits are rigid while the second one admits that voltage and branch flow limits are modeled in a soft way using Fuzzy Set concepts. Finally, the paper illustrates the application of these models with a case study using a 55 node MV/LV network.
2010
Authors
João Tomé Saraiva; Mário Hélder Gomes
Publication
7th ICEEM - 7^th International Conference on the European Energy Market, Madrid, Spain
Abstract
This paper describes part of the research developed by the Power Systems Unit of INESC Porto in the
scope of the MoreMicrogrids EU financed project (under the Contract No: PL019864). In this project, and apart from other issues, it was investigated how microgrid agents
could participate in a more effective way in electricity markets. In this paper we present models to enable the
participation of microgrid agents in the provision of ancillary services, namely reactive power/voltage control,
active loss balancing and demand interruption. This participation is accomplished after running the day-ahead market and it corresponds to the activation of a specific market to
allocate these services. The implementation of this kind of models
can contribute to create a new stream of money to microgrid agents so that they can integrate themselves in a more natural way in power systems, eventually eliminating subsidized tariffs that represent in several countries an increasing amount of the
final end user tariffs. Finally, the paper includes a Case Study to
illustrate the use of the developed approaches.
2009
Authors
Mário Helder Gomes; Tomé Saraiva
Publication
EPSR - Electric Power Systems Research, vol.79, no.6, pp.959-972
Abstract
This paper describes the formulations and the solution algorithms developed to include uncertainties in
the generation cost function and in the demand on DC OPF studies. The uncertainties are modelled by
trapezoidal fuzzynumbers and the solution algorithms are based on multiparametric linear programming
techniques. These models are a development of an initial formulation detailed in several publications coauthored
by the second author of this paper. Now, we developed a more complete model and a more
accurate solution algorithm in the sense that it is now possible to capture the widest possible range of
values of the output variables reflecting both demand and generation cost uncertainties. On the other
hand, when modelling simultaneously demand and generation cost uncertainties,we are representing in
a more realistic way the volatility that is currently inherent to power systems. Finally, the paper includes
a case study to illustrate the application of these models based on the IEEE 24 bus test system.
2008
Authors
Mário Helder Gomes; Tomé Saraiva
Publication
IJEIS - International Journal on Engineering
Intelligent Systems, vol.16, no.2, pp.121-131
Abstract
The restructuring of power systems has often originated the organization of power system operation
planning in a set of chronological sequence of activities that are reasonably decoupled. This means
that the Market Operator purely economic schedule together with bilateral contracts is conveyed to
the System Operator to be validated from a technical point of view. The System Operator also has
to schedule reactive power but some of its reactive power requirements may be unfeasible given the
previous active power schedules and the alternator capability diagram. Apart from this aspect,
active and reactive powers are coupled in determining the eventual violation of branch thermal
limits and reactive power has a well-known local nature. While recognizing the coupling between
active and reactive powers, the models presented in this paper admit that the Market Operator
schedule may have to be altered either because there are branch limit or nodal voltage violations or
because the System Operator requires a reactive output that can not be provided due to the previous
active schedule. The changes on the initial schedule are determined by solving an optimization
problem that uses adjustment generator or demand bids. Apart from that, we adopted a symmetric
fuzzy programming approach recognizing that some constraints have a soft nature, namely the ones
related with voltage and branch flow limits. To solve the resulting non-linear problem we used
Sequential Linear Programmin
2008
Authors
Mário Gomes; Tomé Saraiva
Publication
Proceedings of PSCC2008 - 16th Power Systems Computation Conference, Glasgow, Scotland
Abstract
This paper describes a mathematical model and the developed solution algorithm to solve an integrated active / reactive dispatch while retaining competitive aspects. The main drive for this research was
the recognition that the introduction of competitive mechanisms lead to a certain extent to a decoupling
between active and reactive power scheduling. Aiming at remarrying them, the developed approach includes an
initial bid based uniform price active power auction run by the Market Operator, followed by a technical validity analysis run by the System Operator. If necessary, the
System Operator uses adjustment bids to recover the technical feasibility of the dispatch. These bids are
presented both by the demand and by generators meaning that demand can play an important role in
increasing the liquidity of this specific market. This approach also includes capacitor banks and transformer taps leading to a combinatorial problem solved using
Simulated Annealing. Finally, the paper includes results from a case study based on the IEEE 24 Bus Test System to illustrate the interest of this type of approaches.
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