Structure Design Optimization And Configuration Methods Research On Parallel Gap Device Of 10kV Insulator

In recent years, most cities had replaced bare conductors with insulated conductor on the medium voltage overhead lines to further improve distribution line’s reliability. But new problem—breakage of distribution lines caused by lightening stroke, still occurs, threatening the safety of power grid greatly and making local agriculture and industry production suffer great loss. So it is of great academic value and practical significance to take reasonable lightening protection measures to solve the problem for distribution overhead lines.In sight of traditional lightning protection measures’ limitation and conservativeness, we designed a newly parallel gap lightning protection device with special arc-diverting arm, which can lead the arc to the end of electrodes more quickly, thus to avoid long-time single phase grounding fault by pulling out arc fast.Lightning impulse voltage experiment platform with consideration of wind effects has been built up, and we conducted the experiments to ensure the insulation coordination between 10 k V insulator P-15 and parallel gap lightning protection device under different wind directions and wind speed effects. And results show that: when the air gap is 155.8mm, whether there is effect of wind or not, parallel gap lightning protection device can protect the insulator completely.Based on the chain arc model, we have built up the arc movement simulation model for short-circuit arc on the 10 k V insulator P-15 with breakage-prevention parallel gap device. Furthermore, we have researched the characteristics and the influence factors of arc movement, thus to optimize the electrode design. And the simulation results demonstrate that: the longer horizontal length of the arc-diverting arm, the shorter vertical length of up electrode, the time arc taking move to the end of electrode is longer. Therefore, we recommend horizontal and vertical length of the arc-diverting arm 100 mm and 20 mm respectively.Based on V-t characteristics test results, we have founded simulation model for typical 10 k V distribution lines through ATP Electro-magnetic Transient Analysis Software. And we have analyzed the lightning withstand level and lightning outage rate of distribution line under different installation methods of parallel gap devices and compared the results with that of lines without protection devices. From the simulation results, we have proved the validity of breakage-prevention parallel gap device, and results show that the configuration of installing parallel gap devices every other tower of single phase is proper according to the practice.