Ultra-High-Speed Transmission Line Differential Protection Using an Error Index of Bergeron Equation
Keywords:bergeron equation, differential protection, error index, synchronized measurements, transmission line
Ultra-high-speed and simple protection schemes is a matter of study in recent years. Therefore this document develop a differential protection method in transmission lines using voltage and current traveling waves signals, for which the transmission lines are modeled through distributed parameters and expressed by telegraph's equations which is solved using Bergeron's equations, these equations depend on instantaneous signals and historical components. The fault detection is determined using an error index that compares the voltage and current signals from the ends of the line, for this, signals with synchronized measurements with the same time stamp are considered. This method presents a simple criterion to implement using algebraic operations and a time window between 1 ms and 2 ms. For simulations, a power system is modeled on ATP Draw and many faults cases studies are simulated and considering several conditions such as inception angle from voltage signal, fault resistance, fault distance and internal/external faults. Good speed results are obtained compared with traditional algorithm, also identifies the internal and external areas of its protection adequately. In the case of three-phase systems, the method is developed using the Clarke modal transformation.