Speeding Up Line Differential Protection Using Instantaneous Currents and Memorized Voltages
Fast Differential Protection, Transmission Lines Protection, Power Differential Protection, EMTP-ATP.
This work presents a strategy to enhance the speed of differential transmission lines protection trip. The proposed strategy involves using instantaneous terminal currents and memorized terminal voltages to compute operating and restraint power quantities for each transmission line terminal. The performance of the proposed scheme was assessed through computer simulations using EMTP-ATP, conducted on a simplified test transmission system, which comprised a 500 kV transmission line. Multiple scenarios were examined, incorporating different types of applied faults, varying fault resistances, the fault inception angle, Source Impedance Ratio (SIR), and fault application points along the transmission line. The results of the simulations demonstrate the proposed scheme’s excellent performance in detecting and responding to high and low-impedance faults. Additionally, the method exhibits high sensitivity in identifying internal faults while maintaining selectivity in detecting external faults. This approach can make the protection trip faster and more efficient, ensuring reliable operation and better safeguarding of the transmission lines.