Generalized Generation Distribution Factors Research Articles

Large-Scale Preventive Security-Constrained Unit Commitment Considering N-k Line Outages and Transmission Losses

This paper presents a new formulation for the preventive security-constrained unit commitment problem modeling <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> line outages and transmission losses. The pre- and post-contingency transmission constraints, representing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> line outages, are explicitly included by using generalized generation distribution factors. To account for security, a contingency selection procedure based on line outage distribution factors finds a list of worst-case contingencies. Transmission losses are incorporated using piecewise linear expressions. The proposed model is formulated as an instance of mixed-integer linear programming. The effectiveness of the proposed approach is illustrated with the IEEE 57-bus system and the 1,354-bus portion of the European transmission system. As empirically evidenced, the explicit consideration of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N-k</i> line outages and transmission losses leads to different decisions in the generation scheduling and dispatch, ensuring secure power system operation.

Using Generalized Generation Distribution Factors in a MILP Model to Solve the Transmission-Constrained Unit Commitment Problem

This study proposes a mixed-integer linear programming (MILP) model to figure out the transmission-constrained direct current (DC)-based unit commitment (UC) problem using the generalized generation distribution factors (GGDF) for modeling the transmission network constraints. The UC problem has been reformulated using these linear distribution factors without sacrificing optimality. Several test power systems (PJM 5-bus, IEEE-24, and 118-bus) have been used to validate the introduced formulation. Results demonstrate that the proposed approach is more compact and less computationally burdensome than the classical DC-based formulation, which is commonly employed in the technical literature to carry out the transmission network constraints. Therefore, there is a potential applicability of the accomplished methodology to carry out the UC problem applied to medium and large-scale electrical power systems.

Decoupled Power System Security Dispatch

This paper presents a methodology for solving the Optimal Load Flow problem. The problem is formulated as a non-linear constrained optimization problem, recognizing system losses; operating limits on the generation units and line security limits. The optimization problem is solved by an iterative scheme. At each iteration the Optimal Load Flow problem is decomposed into a real subproblem and a rqactive subproblem. The two subproblems are transformed to quadratic programming problems by utilizing Z-mattix techniques and the Generalized Generation Distribution Factors.

Generalized Generation Distribution Factors for Power System Security Evaluations

A set of Generalized Generation Distribution Factors (GGDF's) is developed to replace the conventional Generation Shift Distribution Factors (GSDF's). This model relates the line flows with generations for a given network configuration. Being in an integral form, new flows on lines can be obtained directly without running load flows when total system generation changes. Conforming load change is also demonstrated. These new factors are especially suitable for constraint formulation in mathematical programning, such as optimal generation dispatch with security contingencies considered