水平顶管工况下高压电缆线芯温度推演与动态增容

Temperature Inversion and Dynamic Capacity Enhancement of High-voltage Cable Conductor Under Horizontal Pipe Jacking Laying

水平顶管一般用于电缆线路穿越河流、街路等场合,由于其特殊构造,导致单独使用光纤测温的实时性和准确性较差。鉴于此,本文提出了电缆端部表皮测温器与置于相邻PVC空管内的光纤测温器的联合测温方案和线芯导体温度推演与动态增容方法。将电缆线芯、表皮分别等效为热源与热汇,电缆内部各部分等效为热网络,根据光纤与表皮测温值反演热路参数值,采用拉普拉斯变换法求解热路,推演各相缆芯实时温度并预测动态增容的应急负荷允许持续时间。通过与有限元计算结果的对比分析,证明了本文模型预测应急负荷持续时间的准确性和快速性。

Horizontal pipe jacking is generally used in situations where cable lines cross rivers,streets,and so on.Due to its special structure,the cable temperature measurement optical fiber is difficult to lay close to the cable skin,resulting in poor real-time and accuracy of temperature measurement when using optical fiber alone.In this point of view,a temperature measurement scheme combining a cable end skin thermometer and an optical fiber thermometer placed in an adjacent PVC empty pipe is proposed,and the corresponding core conductor temperature inversion and dynamic capacity enhancement methods are proposed.The cable core and cable skin are modeled as equivalent heat sources and heat sinks respectively,and the other parts in the cable are modeled using equivalent thermal circuits.The thermal circuit parameters are inverted based on the temperature measurements of the optical fiber and skin.The Laplace transform method is used to solve the thermal circuit model,inverse the real-time temperature of each phase cable core and predict the allowable duration of emergency loads for dynamic capacity enhancement.By comparative comparisons with the finite element results,the accuracy and fast convergence speed of the proposed model and method in predicting the emergency load duration are confirmed.