研究线缆发热与光单元传输特性变化之间的关系对光纤复合低压 电缆(OPLC)设计及应用十分重要。 用COMSOL软件模拟仿真光纤复合低压电缆的稳定运行和短路故障状态,得到其相应的电缆温度分布以及光 单元传输损耗特性。选取线缆上不同位置处的特征点进行仿真,结果表明:电缆故障时导体绝缘层内升温 较明显,外护套温度变化不明显；光纤温度变化很小,在5 s内只有0.2 °C的上升。 由热膨胀引起的位移很小,使得传输损耗在这两种情况下几乎一样,短路故障对光纤的温度影 响不大。设计光单元升温实验得到光缆传输损耗的数据,并与仿真数据进行对比分析。实测温度数据滞 后于仿真数据5 s, 但与仿真数据变化趋势一致,证明了仿真模型的可靠性和可行性。

Investigation of relationship between the heat caused by electricity in cables and change of the optical unit transmission characteristics is very important for the design and application of fiber composite low voltage cable(OPLC). Stable operation and short circuit fault state of fiber composite low voltage cables are simulated with COMSOL software, and the corresponding cable temperature distribution and optical unit transmission loss characteristics are obtained. The characteristic points of different position on the cable are selected for simulation. Results show that the temperature rising is obvious in the conductor insulation layer when the cable is in trouble, and the outer sheath temperature change is not obvious. The fiber temperature change is very small, only 0.2 °C rising within 5 s. The displacement caused by thermal expansion is very small, so that the transmission loss are almost the same in the two cases. Short circuit faults have little effect on the optical fiber temperature. Temperature rise test of optical unit is designed to obtain optical cable transmission loss data, and those are compared and analyzed with the simulation data. The measured temperature data lag behind the simulation data 5 s, but it is consistent with the change trend of simulation data. It is proved that the simulation model is reliable and feasible.