提高导线允许温度的可行性研究和工程实施

Feasibility Study on Increasing Conductor Allowable Temperature and Engineering Practice

导线的允许温度由现行规范规定的 70℃提高到 80℃ ,可提高原有线路输送容量 2 0 % ,降低新建线路投资10 % ,具有显著的经济意义。国内外大量试验数据表明 :(1)导线允许温度提高到 80℃对线材强度无影响 ;(2 ) 80℃时的钢芯铝绞线强度基本上不低于计算拉断力 ;(3)导线温度 80℃时 ,金具温度不超过 6 7℃ ,金具电阻为等长导线电阻的 35 %～ 6 6 % ;金具温度在 80℃以下时 ,对握力没有影响。因此提高钢芯铝绞线 (LGJ或ACSR)导线允许温度到 80℃是可行的。导线允许温度从 70℃提高到 80℃ ,功率损耗和电能损耗增加甚微 ,一般档距增加弧垂 0 .5m左右 ,经论证和 5 0 0kV斗南、斗牌改造工程实践 ,证明采用 5 0℃定位。

Increasing the conductor allowable of 70 ℃ specified by the present specifications to 80 ℃can expand the transmission capacity of the lines by 20% and reduce the of new line by 10%, which is of realistic economic benefits. A great number of both foreign and domestic test data shows: (1) The increase of the conductor allowable temperature up to 80℃ has no effect on the strength of the wire; (2) The strength of the aluminum steel reinforced wire at 80℃ is no lower than the calculated tensile force; (3) As the conductor is at 80℃ and the temperature for the hardware is not beyond 67℃, the resistance of the hardware is 35%～66% of the resistance for the equal-length conductor; as the temperature for the hardware is below 80℃, it has no influence on the holding force. Therefore it is feasible to increase the conductor allowable temperature of the aluminum steel-reinforced wire (LGJ or ACSR) to 80℃.When the conductor allowable temperature increased from 70 ℃to 80 ℃,the power and energy loss has to be increased very little and the sag for a normal span is increased only by about 0.5 m.It has been proved that application of 50 ℃ for position,check of distance to the ground and distance of crossing span is reliable and safe through demonstration and engineering practice of 500 kV retrofitting projects.