1.0.1 In order to implement national capital construction policy and technical economy policy during the design of AC 110kV~750kV overhead transmission line, achieve safety and reliability, advanced application, economy and rationality, resource conservation and friendly environment, this code is formulated.
1.0.2 This code is applicable to the design of AC 110kV~750kV overhead transmission line; thereinto, AC 110kV~500kV is applicable to the design of single loop, same tower and double loop as well as same tower multiple loop transmission line; AC 750kV is applicable to the design of single loop transmission line.
1.0.3 The design of overhead transmission line shall start from practice, combine local characteristic, positively adopt new technique, new process, new equipment and new material, popularize and adopt advanced technology and product with energy conservation and consumption reduction as well as environmental protection.
1.0.4 As for important line and special section line, the proper strengthening measures should be adopted to improve security level of line.
1.0.5 This code specifies basic requirements of design of 110kV~750kV overhead transmission line; if this code interferes with specifications in national laws, administrative regulations, the national laws and administrative regulations shall be conformed to.
1.0.6 the design of overhead transmission line shall not only meet those specified in this code, but also comply with those specified in the national current relevant standards.
2 Terms and Symbols
2.1 Terms
2.1.1 Overhead transmission line
It refers to the power line in which the insulator and tower are used to set the conductor above the ground.
2.1.2 Telecommunication line
It refers to the communication line of various electrical signals.
2.1.3 Large crossing
It refers to the section that the conductor selection or tower design needs special consideration owing to larger span (above 1000m) or higher tower (above 100m) when line crossing navigation river, lake or strait and has a strong impact on navigation or especially difficult repair during fault.
2.1.4 Light/medium/heavy icing area
The area with design ice coating thickness equal to 10mm and below is light icing area; the area with design ice coating thickness larger than 10mm and less than 20mm is medium icing area; the area with design ice coating thickness equal to 20mm and above is heavy icing area
2.1.5 Reference wind speed
It refers to the wind speed determined after obtaining the maximum value once per 50 (30) years through probability statistics by observing data according to 10min time interval at 10m height of local open flat ground and mean annual maximum wind speed.
2.1.6 Rare wind speed, rare ice thickness
They refer to severely strong wind and ice thickness existing according to history record and significantly exceeding frequency curve of past records.
2.1.7 Section
It refers to the line part between two tensile towers.
2.1.8 Everyday tension
It refers to the conductor or earthwire tension of minimum point of sag under mean annual temperature.
2.1.9 Equivalent salt deposit density (ESDD)
It refers to total amount of sodium chloride after dissolution with the same electrical conductivity as natural sedimentation from insulator surface cleaning of given insulator after dissolution divided by surface area, hereinafter referred to as the equivalent salt density.
2.1.10 Non-soluble deposit density (NSDD)
It refers to the total amount of non-soluble residues from insulator surface cleaning of given insulator divided by surface area, hereinafter referred to as ash density.
2.1.11 Weighting foundation
It refers to the foundation with its up-pull stability mainly relying on foundation gravity, and the gravity larger than standard value of up-pull force.
2.1.12 Reinforced concrete pole
It refers to the generic term of ordinary concrete pole, partial prestressed concrete pole and prestressed concrete pole.
2.1.13 Residential area
It refers to the densely inhabited areas as industrial enterprise area, port, dock, railway station and town.
2.1.14 Non-residential area
The area beyond the residential area stated in Article 2.1.13 belongs to non-residential area.
2.1.15 Difficult transport area
It refers to the area inaccessible to vehicle and agricultural machine.
2.1.16 Electrical clearance
It refers to the minimum distance between any alive part and grounded part of line.
2.1.17 Ground clearance
It refers to the minimum distance between any alive part and ground under specified conditions.
2.1.18 Shielding angle
It refers to the included angle between vertical plane crossing earthwire and plane crossing earthwire and lightning protection conductor.
2.1.19 Mining affected area
It refers to the area affected by mining disturbance.
