AbstractsMathematics

The response time of distance protection is influenced to a considerable extent by the characteristics and the response of the primary current and voltage transducers, from which the protection signals are derived. Recent years have seen an increasing demand for distance relays with operating times of approximately one cycle. These relays are affected by high frequency components which are caused by fault induced travelling waves. In attempting to analyse the operation of the high speed distance relay, the precise nature of the system waveforms is necessary. Thus the need for modelling the frequency variance of the transmission line parameters is established. Using modern transmission line theory developed by Wedepohl and Johns it will be possible to predict the fault transient behaviour of a multi conductor lines accurately. The program written shows how the basic matrices of the conductor system are derived, taking into account the effects of conductor geometry, conductor internal impedance and the earth return path. The system matrices were then defined for a faulted system and the solution found.