Study on Sheath Circulating Current and Suppression Measures of 220 kV Urban Long Cable Line
Aiming at the problem that the voltage imbalance of metal sheath of high voltage cables causes the over-limit of sheath circulating current,which affects the safe and stable operation of urban power grids and leads to the alarm shutdown of cable lines,the sheath circulating current due to uneven segmentation,different three-phase axial spacings,and mixed arrangement in the cross-interconnection of 220 kV urban long cable lines is analyzed and calculated,and influence of segmentation degree on the sheathing circulation is evaluated by introducing the uneven segmentation factor,and validated by engineering examples.The results show that the simulation model and calculation results have good accuracy;the size of the sheathing circulation is proportional to the uneven segmentation coefficient of the cable cross-connections for single and double circuits;the use of different axle spacings or mixed arrangements in the same group of cross-connections will lead to an increase in the sheathing circulation under uniform segmentation.It is proposed to utilize different axis spacing to suppress the circulation under uneven segmentation,such as by using larger axis spacing for shorter segments and smaller axis spacing for longer segments to reduce the sheathing circulation.
国家科技期刊平台
NSTL
万方数据
