Wire layout:
Influencing factors: The layout of conductors mainly depends on the number of lines, the reliability of line operation, the rationality of tower load distribution, the convenience of construction, installation and live working, and the tower head should be simple in structure and small in size.
One way: single loop line: triangle, upper glyph, horizontal arrangement; Double circuit lines: umbrella, inverted umbrella, hexagon and double triangle arrangement, as shown in the following figure. Special position: vertical arrangement or triangular arrangement, etc.
The operation experience shows that the operation reliability of single-circuit lines arranged horizontally is better than that of triangular lines, especially in areas with heavy ice cover, many minefields and serious corona. This is because the height of the horizontal line tower is low, and the probability of lightning strike is reduced; When the lower layer wires arranged in triangle jump upward for some reason (such as uneven deicing), it is easy to cause interphase flashover and collision between wires.
However, the tower with horizontal conductor arrangement is more complicated than the tower with triangular conductor arrangement, with high cost and larger line profile. Generally speaking, horizontal layout or triangular layout can be selected according to the specific situation in general areas, and horizontal layout is appropriate for heavy ice areas and minefields, and triangular layout is more economical for lines with less conductor cross-sections below 220kV.
Because the umbrella arrangement is inconvenient for maintenance and repair, and the inverted umbrella arrangement has poor lightning protection, hexagonal arrangement is often used to erect double-circuit lines on the same pole at present. This can shorten the length of the cross arm, reduce the torsion of the tower, obtain a satisfactory lightning protection angle and improve the lightning protection level.