Aplicação de metodologia para determinação de índice de coordenação e seletividade de rede de distribuição com geração distribuída

Abstract

In recent years, the proliferation of distributed generation (DG) in distribution systems has increased significantly. However, protection schemes originally designed to operate with unidirectional energy flow can be negatively affected by the presence of DG, compromising coordination and selectivity indices. This study aims to develop a generalization of a quantification method called the CORSEL index to assess the impact of distributed generation on the power grid. The methodology was developed using the MATLAB® software and Simulink® tool. A baseline case and ten scenarios were analyzed for the same network topology: one without accounting for DG presence and the remaining scenarios with DG injection at specific points in the system. The results showed that the occurrence of reverse power flow affects the test system, depreciating its original global coordination and selectivity levels, particularly impacting the relay-fuse pair. The most detrimental scenarios were those where the DG source was allocated downstream of the recloser. Furthermore, the method is also proposed to be a tool for determining the optimal allocation point of the DG source in the original system, based on the behavior of the system's global CORSEL index. Finally, other impacts of bidirectional current flow in a distribution system are discussed, along with proposed alternatives to mitigate the issue.