Overview Of Domestic Standards And Specifications For Polypropylene Insulated Power Cables And Materials

The standard specifications of polypropylene cable materials are mainly distinguished by insulating materials and semi - conductive shielding materials. There is still a discussion about the maximum operating temperature of the conductors suitable for insulating materials and semi - conductive shielding materials, which could be 90 °C, 105 °C, or even higher temperatures. A higher operating temperature can increase the transmission capacity of cables to a certain extent and is suitable for application environments with greater load fluctuations.

Existing research conclusions show that the electrical properties of polypropylene materials are almost the same as or even better than those of cross - linked polyethylene before modification, but there is a certain degree of decline in electrical properties during the process of improving mechanical flexibility. Therefore, it is necessary to improve the electrical properties through methods such as graft modification and nano - doping to achieve a "force - electricity synergy" effect. At the same time, the long - term performance and economic optimality of the materials also need to be comprehensively considered.

In addition, in the existing standard specifications of cable materials, test items for evaluating the cross - linking degree of thermosetting cross - linked polyethylene, such as the "thermal elongation test", have been cancelled. Test items and evaluation requirements for thermoplastic materials have been added. In the future, more specific test methods and requirements for the thermal properties of thermoplastic materials when used as power cable materials need to be clarified. From the current test results, the assessment of thermal properties is mainly carried out through thermal deformation tests, thermal shrinkage tests, or thermal shock tests. The test conditions still need to be further refined and improved through more practical applications.

In the original standards for cross - linked polyethylene cables or cable materials, only the sheath material had requirements for low - temperature performance, while the insulating material and semi - conductive shielding material did not. The group standards for cables discussed in this paper all clearly require low - temperature impact tests, with test temperatures of either - 25 °C or - 40 °C. The specific selection of the test temperature still needs to be further studied and standardized according to the geographical location (north or south) and application scenarios.