Transient stability constrained optimal power flow using independent dynamic simulation (original) (raw)
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Transient stability-constrained optimal power flow
Focus on Catalysts, 1999
This paper proposes a new approach able to maximize the interface flow limits in power systems and to find a new operating state that is secure with respect to both, dynamic (transient stability) and static security constraints. It combines the maximum allowable transfer (MAT) method, recently developed for the simultaneous control of a set of contingencies, and an optimal power flow (OPF) method for maximizing the interface power flow. The approach and its performances are illustrated by means of simulations carried out on a real world power system.
Stability constrained Optimal Power Flow
Stability Constrained Optimal Power Flow (SCOPF) is necessary to determine a transiently secure Power Scheduling. Till now enegy functions were used to find the margins of stability. In this paper[1] a new methodology is proposed that essentially preserves all the constraints of a standard Optimal Power Flow(OPF) and also be stable for a given disturbance.
Applications of security-constrained optimal power flows
In Proceedings of Modern Electric Power Systems Symposium, MEPS06, 2006
This paper deals with the Security-Constrained Optimal Power Flow (SCOPF) problem. We first revisit both preventive and corrective variants of the SCOPF problem. Then we present the nonlinear Interior-Point Method (IPM) which we use for the solution of the SCOPF problem. Next, we provide numerical results, on a 60-bus test system, for three main SCOPF applications, namely: minimum overall cost of generation, minimum cost of removing congestion and maximum power transfer computation. We finally discuss some critical issues related to the SCOPF problem.
Securing Transient Stability Using Time-Domain Simulations Within an Optimal Power Flow
IEEE Transactions on Power Systems, 2010
This paper provides a methodology to restore transient stability. It relies on a well-behaved optimal power flow model with embedded transient stability constraints. The proposed methodology can be used for both dispatching and redispatching. In addition to power flow constraints and limits, the resulting optimal power flow model includes discrete time equations describing the time evolution of all machines in the system. Transient stability constraints are formulated by reducing the initial multi-machine model to a one-machine infinite-bus equivalent. This equivalent allows imposing angle bounds that ensure transient stability. The proposed optimal power flow model is tested and analyzed using an illustrative nine-bus system, the well-known New England 39-bus system, a ten-machine system, and a real-world 1228-bus system with 292 synchronous machines.
This paper proves the practicality of an iterative algorithm for solving realistic large-scale SCOPF problems. This algorithm is based on the combination of a contingency filtering scheme, used to identify the binding contingencies at the optimum, and a network compression method, used to reduce the complexity of the post-contingency models included in the SCOPF formulation. We show that by combining these two complementary ideas, it is possible to solve in a reasonable time SCOPF problems on large power system models with a large number of contingencies. Unlike most results reported for largescale SCOPF problems, our algorithm uses a non-linear AC network model in both pre-contingency and post-contingency states, optimizes both active/reactive powers flows jointly, and treats the discrete variables. The proposed algorithm is implemented with state-of-the-art solvers and applied to two systems: a national grid with 2563 buses and 1297 contingencies, and a model of the European transmission network with 9241 buses and 12000 contingencies.
State-of-the-art, challenges, and future trends in security constrained optimal power flow
Electric Power Systems Research, 2011
Keywords: Mixed integer linear programming Mixed integer nonlinear programming Nonlinear programming Optimal power flow Security constrained optimal power flow a b s t r a c t This paper addresses the main challenges to the security constrained optimal power flow (SCOPF) computations. We first discuss the issues related to the SCOPF problem formulation such as the use of a limited number of corrective actions in the post-contingency states and the modeling of voltage and transient stability constraints. Then we deal with the challenges to the techniques for solving the SCOPF, focusing mainly on: approaches to reduce the size of the problem by either efficiently identifying the binding contingencies and including only these contingencies in the SCOPF or by using approximate models for the post-contingency states, and the handling of discrete variables. We finally address the current trend of extending the SCOPF formulation to take into account the increasing levels of uncertainty in the operation planning. For each such topic we provide a review of the state of the art, we identify the advances that are needed, and we indicate ways to bridge the gap between the current state of the art and these needs.
Electric Power Systems Research, 2014
A novel approach based on both single machine equivalent (SIME) and trajectory sensitivity methods is proposed to formulate a transient stability-constrained optimal power flow (TSC-OPF) in the Euclidian space, where only one single stability constraint is necessary in the optimization problem to represent all dynamic and transient stability constraints of the multi-machine system. This formulation remarkably reduces the dimension of the optimization problem to one similar to a conventional OPF, resulting in a tractable approach to the preventive control of transient stability in realistic power systems. A unified framework of time domain analysis is proposed, where the transient stability, trajectory sensitivity and SIME analyses are all combined to assess the system's stability and to compute the sensitivity coefficients of the proposed transient stability constraint. Based on these sensitivity coefficients, three non-heuristic selection criteria are proposed to perform the preventive control by rescheduling only a selected number of generators, which is the commonly accepted practice followed by the system's operators. The validity and the effectiveness of the proposed method are numerically demonstrated in the 10-machine 39-bus New England system and Mexican 46-machine 190-bus system.
Global Transient Stability-Constrained Optimal Power Flow using SIME sensitivity analysis
2010
This paper presents a new, importantly improved, approach to Global Transient Stability-Constrained Optimal Power Flow (TSC-OPF). The main practical difficulty of global TSC-OPF has always been the huge dimension of its resulting optimization problem, since all the different approaches of this type reported in the literature require discretizing and including part of the time-domain simulation as additional dynamic constraints, along with a large set of equations as stability constraints, in the Optimal Power Flow problem, so as to be able to take into account transient stability limits. In our previous research, information provided by the Single Machine Equivalent (SIME) method was successfully used to reduce the dimension of the set of transient stability constraints to a single equation, applied at an individual time step. In addition, the length of the time domain simulation included in the OPF problem was also objectively defined, thus reducing the dimension of the set of dynamic constraints. However diminished the size of the optimization problem, it has been found that it is still possible to reduce its dimension. In this paper, new findings using sensitivity analysis and dynamic information from the SIME method are presented which allow for significantly reducing the dimension of the set of dynamic constraints, by limiting the length of the time-domain simulation to be included in the global TSC-OPF to a single (initial) time step, improving in this way its practical application, solution feasibility and execution speed.
Comparison of voltage security constrained optimal power flow techniques
2001 Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.01CH37262), 2001
This paper compares two different Optimal Power Flow (OPF) formulations that consider voltage security in power systems. The techniques are both based on multi-objective optimization methodologies, so that operating costs and losses can be minimized while maximizing the "distance" to voltage collapse. The techniques are described in detail and compared to study their similarities, as well as advantages and disadvantages. The comparisons are based on the results obtained by applying these two methods to a modified version of the 118-bus IEEE test system.
This paper proves the practicality of an iterative algorithm for solving realistic large-scale SCOPF problems. This algorithm is based on the combination of a contingency filtering scheme, used to identify the binding contingencies at the optimum, and a network compression method, used to reduce the complexity of the post-contingency models included in the SCOPF formulation. We show that by combining these two complementary ideas, it is possible to solve in a reasonable time SCOPF problems on large power system models with a large number of contingencies. Unlike most results reported for largescale SCOPF problems, our algorithm uses a non-linear AC network model in both pre-contingency and post-contingency states, optimizes both active/reactive powers flows jointly, and treats the discrete variables. The proposed algorithm is implemented with state-of-the-art solvers and applied to two systems: a national grid with 2563 buses and 1297 contingencies, and a model of the European transmission network with 9241 buses and 12000 contingencies.