高压电缆接头界面压力测试研究

Determination of the Pressure Distribution at the XLPE Cable-rubber Interface in a Self-pressurized Joint

为准确测量高压电缆接头的界面压力以保障接头电气性能良好,设计了橡胶件界面压力测试装置,它采用一个与电缆外径相同的铝质薄壁管,在内部粘贴应变片,用电测法测量橡胶件施加载荷时内壳壁的应变量,再利用有限元分析获得外壁界面压力值。结果表明,设计的测试装置可操作性良好,测试精度满足要求。

The pressure level at the XLPE cable-rubber interface plays a key role in maintaining the electronic properties in high voltage power joints. It has become an important factor of evaluating the performance of power cable joint. Numerous methods to identify the pressure level are still under investigation. In this paper, a hybrid method, which combines experimental and numerical approaches has been proposed to evaluate the pressure distribution at the interface along the cable joint. An aluminum thin-wall hollow cylinder, which has the same outside diameter as the XLPE cable is designed as a dummy power cable. Strain gages are applied to measure the strain magnitude in hoop direction at the inside wall of the cylinder at a number of different locations, while it is stressed at the external surface by the rubber glove. The pressure distribution along the cable is then derived by means of Finite Element Method （FEM） with the known distribution of hoop strain at the inside wall along the cylinder. In our approach, both NASTRAN and ANSYS codes are used to determine the normal stress distribution on the outside surface of the cylinder. The experimental procedures and results are presented in detail. This method provides a new idea to facilitate the evaluation of the pressure at the XLPE cable-rubber interface and is precise enough for engineering acquirement.