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In recent years, the penetration of renewable resources in electrical power systems has increased. These renewable resources add more complexities to power system operations, due to their intermittent nature. As a result, operators must acquire additional reserves in order to maintain reliability. However, one persistent challenge is to determine the optimal location and quantity of reserves; this...
This paper presents a model to include a security constraint for wind power plant in a hydrothermal dispatch problem. The proposed Unit Commitment (UC) is an augmented problem to take into account different scenarios of wind speed during the day. The wind farms are represented by a linear model that the generations are considered proportional to the availability of wind. The proposed optimization...
In this paper an algorithm is developed for solving the Optimal Power Flow (OPF) and Security Constrained OPF (SCOPF) problem in mixed AC/DC grids. Non-linear models are used for power lines and AC/DC and DC/DC converters. The converter models include terminal losses and power rating constraints. The formulation of the SCOPF problem is such that it works for preventive OPF where no corrective actions...
In order to have a reliable and secure power system, frequency stability should be guaranteed. Primary Frequency Response (PFR) is used to arrest the frequency deviation upon a contingency. The significant penetration of wind generation in power grids has negative effect on the PFR, as the contribution of wind machines to the total system inertia is low and classical wind turbines do not have PFR...
Aggregations of controllable loads can provide reserves to power systems; however, their reserve capacity is uncertain and affected by ambient conditions like weather. Past work proposed a stochastic optimal power flow formulation that used chance constraints to handle uncertain reserves and generation from wind. The problem was solved with a scenario-based optimization method. In this paper, we assume...
In this paper we present a merging procedure which is used to build a consistent description of the European network based on the data provided by the different Transmission System Operators (TSOs). In order to deal with inconsistencies in the data, we introduce a modified Optimal Power Flow (OPF) minimizing the deviation from TSOs data. Results on the European network demonstrate the interest of...
Recently, convex “moment” relaxations developed from the Lasserre hierarchy for polynomial optimization problems have been shown capable of globally solving many optimal power flow (OPF) problems. The moment relaxations, which take the form of semidefinite programs (SDP), generalize a previous SDP relaxation of the OPF problem. This paper presents an approach for improving the computational performance...
DC Independent System Operator (DC-ISO) is a single entity dedicated to coordinate, to control and monitor the operation of the DC transmission system. It will be responsible for ensuring the reliability and security of the multi-terminal HVDC (MTDC) system in real-time and co-ordinate the supply of and demand for electricity, in a manner that avoids violations of technical and economic standards...
This paper describes the resolution of the optimal power flow (OPF) problem in the context of competitive electricity markets with a voltage stability constraint (VSC) based on the estimation of a voltage stability index (VSI) by means of an artificial neural network (ANN). The complexity of a VSI-based VSC consists in determining the VSI critical value. Thus, a methodology based on ANN for explicitly...
We present a computational tool for solving semidefinite relaxations of multi-period AC optimal power flow (OPF) problems. Chordal conversion techniques are used to exploit problem sparsity. Three features set it apart from similar implementations: First, a new, concise real-valued model exploits the problem structure and avoids introducing redundant constraints. Second, a dynamic choice of constraint...
In Italy, many demonstration projects were sponsored and funded in order to develop intelligent automation techniques able to achieve efficiency, reliability, and security of power distribution grids. One of these projects, conducted by A.S.M. Terni S.p.A. (an Italian distribution system operator), concerns the voltage profile control along MV feeders and the power-factor correction at HV/MV primary...
In this work, transient stability constraints are incorporated into the Optimal Power Flow (OPF) problem by converting differential equations in a set of numerical equivalent algebraic equations. Then a procedure of multi-step optimization is proposed in this paper to minimize convergence problems and speeding up computation. The proposed procedure was successfully tested on a 3-machine system, having...
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