基于电磁耦合的电缆导体运行温度直接测量方法

Direct Measurement Method for Operation Temperature of Power Cable Conductor Based on Electromagnetic Coupling

为测量电缆导体运行温度,提出了一种基于电磁耦合原理的电缆导体运行温度直接测量方法,通过在电缆接头处植入测温传感器,直接获取电缆导体的运行温度。与现有的测量电缆表皮温度后根据热力学模型计算导体温度的方法相比,该方法可以快速精确测量电缆接头处导体的实时温度,从而及时发现局部发热点。根据传感器电路结构的不同,直接测温技术分为2种基本方式:有源传感器方式和无源传感器方式。有源传感器方式的测温精度较高,而无源传感器方式则具有传感器体积小、测温范围宽的优点。详细介绍了一种有源传感器测温模块的安装方法,并搭建了测试系统,进行了阶跃电流下单芯110kV电缆的模拟现场温升试验。结果表明,植入的传感器模块不影响电缆接头的电气性能,所测温度与模拟回路直接测量的温度曲线在形状及响应趋势上完全一致,验证所提出方法的有效性。

To obtain the conductor temperature of power cables, we propose a method that directly measures the temperature in real-time through a sensor embedded in the junction of the power cable. Compared with conventional methods, which usually calculate the conductor temperature from the measured surface temperature of cables based on heat transfer models, the proposed method prevails in both response speed and precision, as well as in the speed of locating hot spots. According to the different structures of sensor circuits, two basic methods can be employed for direct temperature measurement of power cable joints, i. e. , the active sensor method and the passive sensor method. The active sensor method has higher precision, while the passive sensor method occupies smaller sensor space and has a wider measuring range. A detailed application of an active sensor module is designed, and then is tested in measuring the temperature rise of a 110 kV cable conductor under step current in a test system. The results show that, without affecting the electrical properties of the cable joint, the embedded module can obtain temperature curves coinciding with those measured through a simulative circuit in both shape and trend, proving the effectiveness of the proposed method.