Abstract: A navigation system is able to find an optimum route to a destination even when a large non-digitized area exists between a starting point to the destination. The navigation system produces processing points based on a particular shape and size of the large non-digitized area and determines whether such processing points should be used for route search operations. When it is determined that the route search operation is effective, the navigation system performs A* algorithm search operations with respect to the start point, processing points and the destination and detects an optimum route to detour the large non-digitized area.

Abstract: A Voltage Instability Predictor (VIP) estimates the proximity of a power system to voltage collapse in real time. The VIP can be implemented in a microprocessor-based relay whose settings are changed adaptively to reflect system changes. Only local measurements (voltage and current) at the bus terminal are required. The VIP detects the proximity to collapse by monitoring the relationship between the apparent impedance {overscore (Z)}app and the Thévenin-impedance. In addition, we disclose: (1) that the VIP may be used in connection with non-radial topologies; (2) a new, more robust method to track voltage collapse in terms of impedance using rolling sums; and (3) a new method for representing distance to voltage collapse in terms of power margins.

Abstract: A Voltage Instability Predictor (VIP) estimates the proximity of a power system to voltage collapse in real time. The VIP can be implemented in a microprocessor-based relay whose settings are changed adaptively to reflect system changes. Only local measurements (voltage and current) at the bus terminal are required. Contrary to the most common strategy to maintain voltage stability, which is to shed blocks of load when the voltage drops below a certain fixed threshold, which threshold is difficult to select since voltage magnitudes are a poor indicator of how close the system is to a collapse, the inventive VIP detects this proximity to collapse by monitoring the relationship between the apparent impedance {overscore (Z)}app and the Thevenin-impedance circle.