Adaptive single-phase autoreclosing of high-voltage transmission lines based on steady-state parameters

Аннотация

Conventional adaptive single-phase autoreclosing (ASPAR) of extra-high-voltage transmission lines that uses the RMS voltage on the disconnected phase as the information-bearing parameter may have a dead band when high power is transmitted via the transmission line. This is caused by excess voltage during arcing after the arc extinction. The line end voltage under grounding arcing is determined predominantly by the longitudinal emf induced by the currents in the healthy phase. At the limit power-transmission angles, this voltage exceeds the recovery voltage after extinction of the secondary arc, which does not allow monitoring the status of the arc by the voltage. Using simple mathematical models, the existence of dead bands for both uncompensated and shunt-compensated lines (using four- or three-beam reactors) is shown. To establish the secondary arc extinction, it is proposed to monitor the voltage phase. The feasibility of the “phase” method was studied using a transmission line model based on matrix n-poles. The model considers the wire transposition and the nonlinearity of the grounding arc. Fundamentally, the phase method does not have any dead bands; however, owing to low arc channel conductance, a minor dead band may occur at large transmission angles and short circuits near the side of the voltage measurement. The restrictions to application of the “phase” method to the ASPAR are established and its typical dead band is identified.