Practical experience with travelling wave fault locators on Scottish Power's 275 & 400 kV transmission system

This paper describes how since 1993, Scottish Power (UK) has installed and operated travelling wave fault locators (TWFLs) on its 400 and 275 kV power transmission lines, including all interconnectors with the Scottish Hydro National Grid Company. Accurate fault location, i.e. to better than +/-300 metres, was identified as a crucial element in Scottish Power's strategy to improve power system availability by reducing restoration times for permanent faults and identifying areas of repeat faults where preventative measures could be used to reduce the incidence of faults, thereby increasing the quality of the power supply. The decision to adopt TWFL techniques was taken in the light of some 15 years unsatisfactory experience with equipment based on reactance methods.