Two-Port Equivalent Impedance Updates for Substation Topology Changes

The patent segments the network into local sections around the transmission line of interest. Instead of using complete network topology, it calculates the two-port Thevenin equivalent using only local impedance information and topology data from adjacent buses, thereby reducing computational complexity while maintaining sufficient accuracy for protection functions.

The patent applies local quality by using only the necessary local network information (impedances and topology of adjacent buses) rather than global network data. This localized approach reduces the data requirements and computational burden while providing accurate enough equivalents for substation-level protection applications.

The patent divides the network information requirement into segments, using only local impedance data and topology from adjacent buses. This segmentation enables substation devices to perform updates independently using locally available information, improving ease of operation while maintaining reliability through the use of sufficient local data.

The patent enables substation devices to self-update their equivalent models using locally stored impedance information and received topology update signals. This self-service capability eliminates dependence on repetitive updates from central control centers, improving both ease of operation and responsiveness to topology changes.

The patent stores impedance information and basic topology data locally at substation devices in advance. When topology changes occur, these pre-stored data enable immediate decentralized updates without waiting for complete network information, improving responsiveness while maintaining sufficient precision through the use of accurate local measurements.

The patent uses partial network information (local impedance data and adjacent bus topology) rather than complete network topology. This partial information approach provides sufficient precision for protection functions while enabling fast decentralized updates, representing a practical compromise that achieves both responsiveness and adequate accuracy.

The patent performs preliminary calculations of terminal currents using stored impedance information and measured voltages before topology changes occur. This preliminary action eliminates the need for repeated short circuit experiments, reducing time loss while maintaining measurement precision through computational methods based on accurate pre-stored data.

The patent replaces physical short circuit experiments with computational calculations. Instead of creating actual fault conditions to measure terminal currents, the system calculates equivalent terminal currents using stored impedance data and measured voltages, eliminating time loss and safety risks while maintaining measurement precision.