Dynamic Adaptive Protection based on IEC 61850

In electrical power systems, the overcurrent relays (ANSI/IEEE 50/51) are widely used for protection, and it is one of the main alternatives for identifying system faults. In radial systems supplied by a single source, protection and selectivity can be achieved using the traditional techniques based on time-current curves coordination. However, in a system with multiple sources and operational conditions, traditional techniques are not sufficient to obtain selectivity. This paper presents an adaptative protection system which, based on IEC 61850, adjusts the protection to changes in the power system. The proposal uses a communication network to change the overcurrent settings according to the sources in operation. The performance of the proposed system was evaluated in a case study. The system is composed of five independent power supplies, a utility and four cogeneration units with different rated power; thus 15 combinations of sources are possible during islanding conditions. The results demonstrate that the proposal can provide the selectivity of the system in any operational condition.