Preventive methods against blackouts based on protection security assessment in future grids

The paper presents a new automated method for assessing the security of protection systems concerning selectivity and speed to reduce the risk of unnecessary disturbances and blackouts. The invented algorithms are capable to handle complex structures. Hence, the system behavior of a protection system and network is analyzed and assessed as a whole and it has not to be reduced to its single components or devices. The simulation tool is used as an engine to provide the possibility of a holistic simulation of networks together with the protection. The system-method can be divided into two main approaches: Fault pattern analysis (FPA) and economic impact assessment (EIA). The FPA calculates running faults through the whole grid for diverse scenarios of load flows. Economic aspects of nonselective protection systems are also be introduced and presented by the EIA method. It benefits from the fact that protection devices violating dependability or security will lead to additional outage. This outage is calculated and evaluated by the differences of simulated outage and unavoidable outage. The large amount of resulting data is stored in a central database. Intelligent filtering and data preparation allow a holistic assessment and visualization of complete networks of different architecture. Routinely checks of contingency sequences with the presented methods will reveal bottlenecks of the protection behavior itself and of the coordination of network and protection.