Research On Restriction Of Secondary Arc In UHV Double-circuit Lines

UHV transmission line faults are mostly transient and single-phase to ground faults,we often adopt the method of single-phase reclosing to remove it.Because the voltage is high and the distance is long,the secondary arc phenomenon is becoming more serious,if we do not adopt effective measures,the secondary arc will be difficult to extinguish,which directly affects the successful implementation of single-phase automatic reclosure.So,it is neeessary to deeply study on the characteristics of secondary arc and what measures to restrict the secondary arc occurrence.At first,for shunt reactors in double-circuit transmission lines,we often adopt the method of shunt reactor with neutral reactor to extinguish secondary arc,the choice of netural reactor is crucial in double-circuit lines,suitable neutral reactor can not only reduce the arc current and the recovery voltage,but also avoid resonance.This article adopt the method of six sequence component on double-circuit lines,using the knowledge of matrix that obtain formulas to neutral reactor when decoupling.Secondly,in the shunt reactor with neutral reactor and high-speed grounding switch lines,we analysis the capacitive and inductive component of the arc current and the recovery voltage,and then derive the expression of arc current and the recovery voltage in two kind of extinction measures.According to its expression,we qualitatively analyze the changes in a variable that impact to arc current and recovery voltage.Thirdly,because the characteristics of the arc is complex,the conventional analysis is often replaced with a fixed resistor,which lead to the simulation results that can not reflect changes in voltage and current of the fault,in this paper,we establish the fault model in double-circuit line with transient simulation software ATP-EMTP,arc model are embedded in the circuit,thereby extracting more accurate electrical quantities for subsequent simulation.Finally,according to theoretical expressions of arc parameters in neutral reactors and high-speed grounding switch lines,and then present simulations of line length,transposition way,compensation degree,HSGS grounding resistance,arc resistance and so on,and we summarize the impact on arc current and the recovery voltage of each amount.Based on this,the secondary arc self-extinguishing and recommended reclosing time are given in shunt compensation lines or not.