Voltage sag estimation of real transmission systems for faults along the lines

In this paper, we dealt with the problem of the voltage sags due to faults along the lines using the Fault Position Method (FPM). The objective of the study was to demonstrate that for actual transmission systems the FPM can be used in a very effective way to solve real problems with acceptable accuracy and reduced computational times. A very simple procedure for adding further fault positions along the lines, if needed, is proposed. Numerical applications provide evidence of the proposed method. The results obtained were based on a portion of the Italian transmission system and the quantities we used were obtained from the data of the TSO.