Digital simulation of fault arcs on long-distance compensated transmission systems with particular reference to adaptive autoreclosure

There is an increasing demand for more detailed and accurate modelling of fault arcs on Extra-High Voltage (EHV) transmission systems. This is particularly so in relation to the design and development of alternative and improved equipment such as adaptive autoreclosure schemes and new protection techniques. This paper discusses in some detail techniques that have been developed to model fault arcs more realistically, including a time-dependent dynamic resistance model of the primary arc and significant improvements that have been made in the dynamic conducting characteristic of secondary arcs. The statistical character of the secondary arc has been sufficiently taken into account by the dynamic conducting and reignition voltage characteristics. The new techniques are then employed for the simulation of fault transients on a long-distance compensated system. In this respect, the evaluation of shunt compensation is also outlined, because special compensation schemes are essential for reducing the secondary arc current and recovery voltage to levels commensurate with rapid extinction in long-distance lines. The paper concludes with a study of the implications of the simulation results in respect of the design of adaptive autoreclosure schemes by identifying interesting features of the waveforms.