基于有限容积的电缆群载流量计算和分析

Calculate and Analysis Ampacity of Cable Cluster Based on FVM

精确计算地下电缆的载流量和温度场对确保电缆安全和经济的运行很有意义。IEC60287标准给出了单一媒质即均匀土壤中电缆群稳态载流量的计算方法,并给出了有回填土的电缆群载流量修正计算方法。该文在土壤区域采用有限容积的数值法,在电缆区域采用等值热路的解析法,并将两者有效地结合起来。具有比等值热路法计算准确,比单纯数值计算快速的优点。对IEC计算特别是有回填土情况的修正计算,有很好的指导意义。

Accurate calculation of underground cable ampacity and temperature field to ensure safety and economical of cable is very meaningful. IEC methods for calculating cable ampacity assume that buried cables are surrounded by a single, homogeneous material. These ampacity methods have limited application when a thermal backfill is used. IEC correction methods are presented to calculate cables＇ ampacity of non - homogeneous soil. Based on the Finite Volume Method （FVM） of field-circuit coupling theory, a new numerical calculation method of cable ampacity of non-homogeneous soil is presented in this paper. The numerical calculation method which is accomplished through the calculation of cable temperature field distribution can deal with any combi- nation of backfill materials that are placed adjacent to the cable. The thermal circuit is used to model the tem- perature rise of cable in cable areas. The FVM is used to model the temperature rise of the cable in soil areas. The thermal circuit and FVM are combined effectively by the new method in this paper. Compared with thermal circuit, the new method is accurate and can be coped with any complicated soil structure. Compared with FVM or combinatorial coordinates, the new method calculates quickly. The calculation method have a good guide To the IEC especially of backfill modified.