Abstract
This study addresses the problem of the maximization of the voltage stability index (λ-coefficient) in medium-voltage distribution networks considering the optimal placement and sizing of dispersed generators. The problem is formulated through a mixed-integer nonlinear programming model (MINLP), which is solved using General Algebraic Modeling System (GAMS) software. A numerical example with a 7-bus radial distribution network is employed to introduce the usage of GAMS software to solve the proposed MINLP model. A new validation methodology to verify the numerical results provided for the λ-coefficient is proposed by using recursive power flow evaluations in MATLAB and DigSILENT software. The recursive evaluations allow the determination of the λ-coefficient through the implementation of the successive approximation power flow method and the Newton–Raphson approach, respectively. It is effected by fixing the sizes and locations of the dispersed sources using the optimal solution obtained with GAMS software. Numerical simulations in the IEEE 33- and 69-bus systems with different generation penetration levels and the possibility of installing one to three dispersed generators demonstrate that the GAMS and the recursive approaches determine the same loadability index. Moreover, the numerical results indicate that, depending on the number of dispersed generators allocated, it is possible to improve the λ-coefficient between 20.96% and 37.43% for the IEEE 33-bus system, and between 18.41% and 41.98% for the IEEE 69-bus system.
Highlights
Ingeniería Eléctrica, Facultad de Ingeniería, Universidad Distrital Francisco José de Caldas, Facultad de Ingeniería, Universidad Distrital Francisco José de Caldas, Bogotá 110231, Colombia; Laboratorio Inteligente de Energía, Facultad de Ingeniería, Universidad Tecnológica de Bolívar, Abstract: This study addresses the problem of the maximization of the voltage stability index in medium-voltage distribution networks considering the optimal placement and sizing of dispersed generators
We propose two recursive validations using the successive approximation power flow method in the MATLAB programming environment [33] and the Newton–Raphson power flow method in DigSILENT software [34], which allow the final value of the λ−coefficient to be verified via an iterative procedure by fixing the sizes and locations of the dispersed generators based on the solution provided by General Algebraic Modeling System (GAMS) software
The voltage regulation bounds were relaxed to Vmax = 1.20 pu and Vmin = 0.30 pu to ensure that GAMS software solves the optimization model (1)–(9), since the primary objective is to determine the maximum value of the λ-coefficient before reaching the voltage collapse point, implying that the typical regulation bounds of ±10% do not correspond under this extreme condition
Summary
The problem of the maximization of the voltage stability margin by considering the optimal placement and sizing of dispersed generators in AC distribution grids can be formulated through an MINLP model [21]. The integer part of this formulation corresponds to the decision of whether or not to locate the dispersed sources, while the continuous part of the model is associated with the electrical variables, such as voltages, power, and current flows. The complete mathematical formulation of the studied problem is presented below
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
