Protection philosophy for distribution grids with high penetration of distributed generation

•A improvement in the protection philosophy of a distribution feeder with high penetration of distribuem generation is proposed.•High penetration of Distributed Generation can cause several problems to the protection system.•Protection relays assertiviness in this case can be as low as 25% if no improvement is made.•The proposed protection philosophy improvement uses protection and logic functions that already exists on the protection relays and reclosers.•With the proposed protection philosophy, the assertiviness reaches 100% for all relays/reclosers of the distribuition feeder. Distributed Generation (DG) can cause several problems in electrical systems that are not prepared to deal with these new sources: situations such as bidirectional power flow and large variations in short-circuit current values. This article presents changes in the actual distribution systems protection philosophy that intend to make the protection system always work properly and reliably eliminate any short-circuit. Furthermore, it shows that the actual philosophy is inefficient in systems with high DG penetration level and, through modifications in the actual philosophy, using available functions in the protection devices, it is possible to increase the reliability and assertiveness of the protection system for any fault.