Répartition optimale de la production électrique avec une contrainte de stabilité transitoire établie par une approche statistique

Abstract

The transient stability constrained optimal power flow (TSC-OPF) is a big challenge in the field of power systems because of its high complexity and extensive computation effort involved in its solution. The main objective of this thesis is to provide a solution to the problem of transient stability constrained optimal power flow (TSC-OPF). This solution should be done in short time. The final solution of the problem of TSC-OPF results a new operating point which ensures the stability of the power system. To meet this objective, this work is structured in three main parts : First, an analytical function is computed to estimate the constraint of transient stability which is presented by the critical clearing time CCT. Given the huge dimensionality of the problem, a statistical analysis is firstly used for reducing the number of input variables in an initial database to those which are significant in computing CCT. To provide the CCT in functional form, we construct a new database by using design of experiment (DoE). Taguchi design (table) was used to build this database which provides only the significant parameters. The aim of this step is to reduce the number of the operating points in the database. Then, the CCT is computed by using time domain simulation. However, to compute the CCT by time domain simulation, the non significant parameters are also needed, for this; these parameters are fixed in the solution of optimal power flow. Finally, a statistical model is established by using Dual-Kriging method to predict the CCT. This model was subsequently evaluated by several criteria. The results of the evaluation indicate that the CCT estimated by the proposed function is nearly equal to that computed by time domain simulation method. Second, the proposed function in the first part of this work is used to solve the problem of transient stability constrained optimal power flow TSC-OPF. The estimated CCT is considered as a single transient stability constraint which will be subsequently included with the constraints static of power flow. The interior point (IP) optimization method is used to solve the problem of TSC-OPF. This method was modified to accelerate the convergence of the optimization. The interior point method required the computation of the jacobian and the hessian matrices, for this the first and the second derivatives of all the constraints are needed. The solution of the problem of TSC-OPF provides a new operating point which ensures the stability of the power system. In this study, only fist-swing transient instability phenomena are considered. Third, this methodology was tested by using two power systems which are New England 10 machines – 39 bus and 50 machines – 145 bus power systems. Three contingencies were considered for New England system and one for 50 machines network. The multicontingency is also considered for the New England. Consequently, four functions of CCT were computed (each contingency has a specific function). The results show that all the obtained re-dispatching points from the proposed program of TSC-OPF ensure the stability of the power system. The obtained points were tested by using time domain simulation; the results confirm the stability of the systems in all cases of study.

Date	2 Feb 2015
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Louis-A. Dessaint (Supervisor)