Study On The The AC Corona Onset Voltage Characteristicsof T-type Wireafter Elergizedicing

The T-type wires have been given high attention in the design of the transmissionline. However, the corona is needed to focus on considering on the design andoperation issues. At present, domestic and foreign have been done lots of deep researchinto conductor corona inception characteristics with wires under dirty,rain and highaltitude conditions and many tests on conductor icing at the same time, the studiesabout the corona of the wire after icing is very few and there had been no in-depthanalysis, furthermore about the T-type little. Different types of ice change the wireconductor surface morphology resulting electric field distortion so that it affects theonset voltage of the wire.This article uses Multifunction artificial climate chamber in different condition tomake glaze icing,rime icing,mixed-phase icingunder different electric field to fourT-typeconductor:JRLX/T-150/28,JRLX/T-240/28,JRLX/T-310/40,JRLX/T-517/71.Then measure and analysis the icing corona onset voltage of the wire by using ultravioletimager and curve fitting and analyze the ice surface field strength according to thefinite element model.At the same time, how different conductivities affect conductorcorona onset voltage under glaze ice coating condition was studied. and combined withthe icing morphology to establish icing branches’ electrical field model to research thecorona characteristics on the conductor.The test results show that different forms of ice will result in tile corona onsetvoltage decreases,the effect of the glaze is more prominent. Under15min icing time,corona inception voltage will decrease to40%compare to conductor with on icecoated, rime icing decreases by about50%, mix-phase icing decreases by about40%.The larger the diameter, the higher the corona onset voltage of T-type wire,and insame diameter,the corona onset voltage of T-type wire higher than traditional wire.Under the same icing time, As icing farms increased, the glaze icing and mix-phaseicing corona onset voltage of the T-type wire will show decreasing first and thenincreasing,but the rime icing corona onset voltage of the T-type wire will showfluctuant trend.As the icing time increases the corona onset voltage will decrease continually butthe speed becomes saturated under the glaze and themixed-sung, on the other hand,under the rime ice he corona onset voltage will also decrease continually in the early time, after that increase but the speed also becomes saturated;The icing morphology does not vary with the increase of the freezing-waterconductivity, but the conductor corona starting voltage will decrease gradually underthe glaze icing, the conductor corona starting voltage under the glaze icing andmix-phase icing nearly have nothing with the freezing-water conductivity;Simulation results show that icicle and icing trees will distort the conductorsurface electric field seriously, even in very low voltage it also can generate the coronaphenomenon.The trends of field strength of iced T-type wire coincide with experientalresults.