Metodologia para análise da influência de pequenas centrais de geração síncrona na margem de estabilidade de tensão

Abstract

The insertion of Distributed Generation has become a strong attraction due to its characteristic advantages, such as the reduction of losses in the energy transportation due to the lack of extensive transmission lines, decongestion in the transmission and distribution systems, low environmental impact, reduction of investments for improvements in the traditional network, and proximity to the final consumers, which creates a greater reliability to the load service. Small hydro power plants (SHP) are part of the group of distributed generation sources, providing clean energy and a low environmental cost. Thus, SHP provides an interesting solution to the problems involving overloading of the electric power systems and the growing demand for electric energy. However, this innovation leads to changes in the electrical system that may provoke doubts about the security and safe operation. Therefore, the analysis and studies of the electric power system face to these new generations become a need. Among the several related issues, the study of voltage stability is of great interest, since it is a factor that directly influences the operational safety of the system. Voltage instability is capable of causing large load losses and collapses in significant parts of the system, even if they occur due to simple events such as changes in load profiles. Several factors may influence on the stability conditions, especially in systems that operate under stressful conditions, where large consumer centers are far from large power plants, thus requiring extensive transmission lines and equipment for voltage control and reactive compensation. In addition to these factors, the main cause of the occurrence of voltage instability is the inability of the system to provide an adequate support of reactive power throughout the electrical system. In this context, this work presents a methodology for analyzing the impact that SHPs may have on the voltage stability margin. The analysis is accomplished with the support of the computational tool ANAREDE, from the evaluation of the system conditions and curves surveys through the application of the continuous power flow. The main idea is to verify how the insertion of distributed generators can be useful and collaborate to maintain the voltage stability, even if it operates under critical conditions.