A new approach to the analysis of stability for small disturbances in distribution systems of electric power distributed synchronous generators

Author(s)

Rodrigo Hartstein Salim

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
• Defense date: 2011-04-19

Examining board members

Rodrigo Andrade Ramos; Carmen Lucia Tancredo Borges; Sergio Gomes Junior; Aguinaldo Silveira e Silva; José Carlos de Melo Vieira Júnior

• Advisor: Rodrigo Andrade Ramos

Abstract

In this thesis, the small-signal stability is studied from the perspective of power distribution systems with distributed synchronous generators. Two specific peculiarities of these systems are addressed: the load and network unbalance, and the proximity of loads to generators. Regarding the first topic, two approaches are proposed to the small-signal stability study of power systems with load unbalance, one based on modal estimation through data obtained from measurements or time-domain simulations, and another one based on a phasorial model of the system with load unbalance and later linearization of the differential-algebraic nonlinear system obtained. Regarding to the second topic, it is observed in this thesis that electromechanical oscillations can induce certain power quality phenomena, notably voltage fluctuations. In this thesis, a structure is proposed and criteria are defined to the study of these fluctuations induced by typical stability problems, considering the study of isolated perturbations and also the statistical study of perturbations. Through this analysis, a procedure for the design of power system stabilizers with clearly defined criteria is also proposed to assist in mitigating the voltage fluctuations induced by electromechanical oscillations. This design procedure is complementary to the stability criteria currently used in the design of power system stabilizers for power transmission systems. The significant advances in both studied topics have also opened a large research field related to the small-signal stability of power distribution systems with distributed synchronous generators. (AU)

• FAPESP's process: 08/03876-6 - Assessment of the impact of damping controllers in the power quality of distribution systems with the insertion of cogeneration
• Grantee: Rodrigo Hartstein Salim
• Support Opportunities: Scholarships in Brazil - Doctorate