Transient stability constrained optimal power flow

Abstract

Stability is an important constraint in power system operation. Often trial and error heuristics are used that can be costly and imprecise. A new methodology that eliminates the need for repeated simulation to determine a transiently secure operating point is presented. The methodology involves a stability constrained Optimal Power Flow (OPF). The theoretical development is straightforward: swing equations are converted to numerically equivalent algebraic equations and then integrated into a standard OPF formulation. In this way standard nonlinear programming techniques can be applied to the problem.

Risk-Based Active Power Redispatch Optimization

“…Several interesting approaches to extending the SC UC/ED and SC OPF with constraints based on transient stability assessment (TSA) may be found in the literature, however, they differ with respect to many criteria. First of all the way of incorporating rotor dynamics into the linear optimization problem spans from using trapezoidal rule [2,3] or Taylor series expansion [4] (to convert differential equations into algebraic ones) to involving direct (or direct-temporal) TSA methods like single-machine equivalent (SIME) [3,[5][6][7] or the transient energy function (TEF) [8][9][10][11]. These methods are used to rank the synchronous machines by their stability margin (or its sensitivity to generation changes) with respect to a considered set of contingencies, however, the critical clearing time (CCT) was used for ranking as well [12].…”

“…The general scheme of the redispatch optimization proposed in this paper is shown in Figure 1. Its basic concept is similar to those described above [2][3][4][5][6][7][8][9][10][11][12][13][14][15], but there are three major differences. First of all, going beyond TSA towards a more comprehensive dynamic security assessment is considered here, where not only transient rotor angle but also frequency and voltage instabilities may be tackled-by applying proper dynamic models [7].…”

“…In between the dynamic risk assessment and the remedial actions design, this risk values R are used to verify the stopping criterion and assess whether remedial actions are necessary. In the first approach, a threshold-based stopping criterion similar to the ones described in the literature [2][3][4][5][6][7][8][9][10][11][12][13][14][15] was used and its aim was to allow stabilizing the system against credible contingencies. It was defined by the following inequality (2):…”

Transient stability improvement: a review and comparison of conventional and renewable-based techniques for preventive and emergency control

“…Due to cost efficiency, the dispatch of generators is usually determined by the use of optimal power flow (OPF) calculations where either transient stability constraints are derived from a time-domain sensitivity analysis, or the whole set of power flow equations is directly included in the OPF formulation [14][15][16][17]. In [14], a 4 th -order Taylor expansion is used to speed up solving of OPF calculations including transient stability constraints. The authors of [15] propose to derive linearized transient stability constraints outside the OPF calculation to not further complicate the OPF formulation.…”

Double-layered distributed transient frequency control with regional coordination

“…Work [5] studies the relation between power injection disturbance and frequency overshoot of individual bus without active control to regulate frequency transients. On the other hand, to actively control power network transients, several strategies have been investigated, including inertial placement [6], power system stabilizer [7], and power supply re-allocation [8]. Yet, these The authors are with the Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093, USA, {yifuzhang,cortes}@ucsd.edu strategies, aiming at improving system transient behaviors, cannot rigorously constrain the evolution of frequency to stay within a safe region.…”