An improved method for the digital protection of high voltage transmission lines

This paper explores the accuracy of the digital methods for protection of high voltage transmission lines under transient fault condition on a long line and describes an improved method for future digital protection schemes. With this method it is possible to calculate R and L of high voltage transmission lines so that any number of harmonics on the current and voltage waveforms can be eliminated and it is shown to be suitable for distance protection during the first cycle of fault occurrence.