配电网架空绝缘导线暂态载流能力计算与评估

Calculation and Evaluation for Transient Current Carrying Capacity of Overhead Insulated Conductor in Distribution Network

摘要:

城市配电网用电负荷快速增长和供电走廊稀缺会造成用电高峰时期部分配电网供电线路出现重载或过载现 象，威胁电网运行安全。输电线路暂态载流能力实时计算与评估对于缓解当前城市配电网供电紧张的局面具有重要 意义。基于架空绝缘导线等值热路模型、导线热平衡方程和导线暂态温升微分方程组，并考虑日照等外界热源条件 和风、雨水等外界有利散热因素，提出了架空绝缘导线暂态载流能力评估方法。根据该计算模型重点分析了导线温 升过程，计算了导线暂态载流量和安全运行时间。最后，基于架空绝缘导线的在线监测系统数据，评估了实际运行线 路暂态载流能力。研究结果表明: 现行运行规程规定的线路载流量限值过于保守，配电网架空导线具有很大的供电 潜力。

Abstract:

The load of urban distribution network is increasing rapidly，and the power supply corridor is becoming increasingly rare especially in the central area of city，which causes overload or heavy load of some important overhead transmission lines． So the real － time calculation and evaluation of transient current carrying capacity of transmission lines are significant to relieve the tension in power supply． Based on the equivalent thermal model of overhead insulated conductor，the thermal balance equation and transient temperature rise equation set，the evaluation method of transient current carrying capacity is presented considering the effect of sun，wind and rain． The conductor temperature rise is analyzed according to the proposed model，and the transient current carrying capacity and safe running time of the line are given by the calculation methods． Furthermore，the current carrying capacity of a real overhead insulated transmission line is evaluated based on the online monitoring data． The research results show that the current carrying capacity of transmission line is too conservative in the current standards，and the overhead lines of distribution network has a significant power supply potential．