IEEE P1863-2019 pdf download

IEEE P1863-2019 pdf download.Draft Guide for Overhead AC Transmission Line Design.
Some aditional measures such as pplication of RTV coating may be required when
porcelain or glass insulators are used in coastal areas (mo more than 3 km from the sea),
sal lake, sl-r-ated roadtway or ouher heawily pllutledld areas.
(2) Composite insulates that can retain exellent hydrophobicity and hydrophobicity
transfer performance through pllulion layers are easier to operate and maintain in areas
with medium or heavier pollution severity. but less suitable for use in dusty environment,
such as a cement plant.
When composite insulators are used in icing areas, the icing performance may be
enhanced by enlaging the shed in a limied range to inbibit bridging through icicles
(3) The ollowing mcasures against icing flashover may be lakcn for insulator strings in
heavy icing areas: alemnate diameter strings. V-type and invented-V-type insulator
strings. These mcasures can minimize the probability of bridging of insulators through
icicles and the probability of icing fashover. Litenature [B27] lists many other available
methods to improve performance of insulatiors under icing conditions.
4.24 Fitings
The fitings of tonsmissis lines shall meet the speeial requirements placed in a speitie
projet, and alow for ease of tansportation, isallatina,n maintenance and replacemen.
The genernal requirements are as fllows
(1) The fitings may have high rliability to maintain the safe and stable operation of
tasnission lines.
(2) The strocture of fttings 25 well as the stroctures connecting the fitings with
insulators, conductors and other fitings may be reasonable and opimally designed;
(3) In sletion of materials, the requirements spcified in 1) and 2) above shall be fully
considered, and dcision be made through comprchensive comparison from the aspeets of
strengh, costL, wrability eltr.
(4) For futing with the corona ise, the basie roquirement that no visible corona is
generated under the highest power frequency volage shall be saisfied Therefore, its
strucure may be secially designed, and can be optimized w ith three dimensional finite
element simulation sftware. The theoretically cnlculaed peak value of operating field
strengh on the surfaee of fiting shall not exced 26kV/cm for atiudes of 000 and
below, and shall meet atitude crrection requirements for higher altiude.
(5) The fitings can be interchangeable for Case of line maintenance.
(6) The frtings used in regions with a low extreme temperature may be made of low-
temperaburc-resislant britle matcrials, and that used in regions W here strong wind occurs
frequently and lasts for a long time may be made of wear-resisant matcrials. For fttings
made of frrous metal, the surface can be hol galvanized or treated with olher proper anti-
corrosion measures.
4.2.5 Support structure
The design of support structures of transmission lines shall meet the following
rquirements:
(1) Support structures shall satisty the roquirements of the ulimate limit states and
serviceability limit states under formal operation load (ineloding such natural loads 85
wind and ice, and potential arifial loads) within the specifiedl design service life. They
shall be able to bear various loads imposed during construction and maintenance. Their
reliability level should be determined in accordance with local laws and regulaions, if
not spcifed, the relative rliabiliy criteria rommended in this guide may be adopted;
(2) The design of spporting structurs should consider the rquirements on publie safety.
endurance, safety, enviromental firndliness,s Cost efetivness and mintainability. In
adition, the visual appearance can also be considered based on the requirements of the
construction environment;
(3) The support structures may be twers or poles. Towers can be composed of angle
steel or steel tube. and poles can be made of seel, wood, reinforced concrete, composite
material. ete:
(4) Based on practical engincering expenhence and accident investigation results, the
selection of tower type for heavy icing areas shall also confim to the fllowing
prineiples: 2) Self-supporting tower with conductors symerically aranged ean be used:
b) Lines in heavy icing areas are featured with large elevation diference. uneven span,
uneven icing or ice shedding, which may lead to high tension or torsion load in the line
direction. Therefore, the tower body can be of a section that has a satisfictar
longiudinal rigidity and torsional rigidity, e) The structural ype of twwers may be
delermined through comprchensive techno economie comparison in view of tho
charateristics of lines in heavy icing areas.