Um novo modelo para representação da regulação primária e secundária de frequência no problema de fluxo de potência e fluxo de potência ótimo

Abstract

This work proposes a new formulation for both the conventional power flow and the optimal power flow formulation, in which the steady-state equations describing the primary and secondary frequency control in electrical power systems are included. The proposed power flow formulation is based on a flexible methodology for the representation of control devices. Such methodology incorporates equations that model control devices into the basic power flow formulation in polar coordinates, generating an augmented system of equations having order (2nb + nc). The developed power flow is able to estimate the system frequency deviation due to a load disturbance. On other hand, the proposed optimum power flow formulation is able to identify the minimum load shedding necessary to maintain the system frequency in an acceptable range of operation. The proposed OPF formulation includes additional equality and inequality constraints to represent the steady state primary frequency control as a function of the active power generation. The proposed development for the conventional power flow was made using the MATLAB® environment. The optimal power flow solution used a commercial optimization package called LINGO®. The evaluation of the proposed power flow and optimal power flow formulations were made through the study of small test systems and the New England test system. Validations of the frequency deviation analysis were made using the program ANATEM, developed by CEPEL. The results obtained show the advantages of using the proposed formulations.