DG and protection systems in distribution network: Failure monitoring system based on petri nets

The paper deals with the problems that can rise in protection systems of the distribution networks in presence of Distributed Generation (DG). A mathematical formalism is introduced to model protection trip problems in radial distribution networks and a procedure to monitor failures of the protection systems based on Petri Nets and a simple matrices manipulation is presented. Such procedure allows designing a tool for a centralized monitoring system of a power protection scheme. In the paper also an architecture to support the tool is proposed and two case studies are simulated on a real Italian distribution network. The proposed approach represents an interesting solution to improve reliability into distribution systems in presence of DG.