ATP-EMTP investigation of adaptive distance protection for transmissions lines with series compensation

In this paper results of investigation of a new distance protection principle for a transmission line compensated with 3-phase capacitor banks installed at mid-line of the line is presented. The delivered distance protection algorithm applies two measurement procedures designated for determining fault loop impedance under faults in front of and behind the compensating bank, respectively. Presence of the resistance at fault is compensated for in both measurement procedures. The algorithm has been tested and evaluated with use of the fault data obtained from versatile ATP-EMTP simulations of faults in the test power network containing the 400-kV, 300-km series compensated transmission line. The sample results of the evaluation are reported and discussed.