工频电压下220kV级XLPE电缆绝缘中电树枝生长特性研究

Propagation Characteristics of Electrical Tree in 220 kV XLPE Cable Insulation Under Power Frequency Voltage

采用实时显微数字摄像技术和局部放电连续测量相结合的实验方法,研究不同外施工频电压下220 kV级XLPE电缆绝缘中电树枝的引发及生长特性,将其结构特征与110 kV电缆绝缘中的电树枝进行对比,利用差示扫描量热法和热失重分析法研究220 kV和110 kV电缆绝缘材料的微观聚集态结构。结果表明:在相同外施工频电压下,220 kV和110 kV电缆绝缘材料中的树形结构相同;在外施电压为9 kV和11 kV下,110 kV电缆绝缘中电树枝的引发时间相对较短,而在高电压等级下两者基本一致;110 kV电缆绝缘中电树枝在9 kV和27 kV下的生长时间相对较长,而在其他电压等级下220 kV电缆绝缘中电树枝的生长时间相对较长。220 kV电缆绝缘材料热稳定性和结晶度更高,结晶速率更快,即具有更好的结晶特性。

The initiation and propagation characteristics of electrical tree in 220 kV XLPE power cable under different voltages were studied by real-time microscope and partial discharge measurement, and then compared with the 110 kV XLPE cable. The aggregation structures of 220 kV and 110 kV XLPE cable insulating materials were studied via differential scanning calorimetry and thermogravimetic analysis. The results show that the electrical trees in 220 kV and 110 kV XLPE cable have the same structure under the same applied voltage. The initiation time of 110 kV XLPE cable was shorter than that of 220 kV XLPE cable under 9 kV and 11 kV, and their initiation time is almost the same under high volt- age. The propagation time of 110 kV XLPE cable is longer than that of 220 kV XLPE cable under 9 kV and 27 kV, but it is shorter at other applied voltages. The 220 kV XLPE cable insulating materials have higher crystallinity, crystallization rate, and thermal stability, that is, it has better crystallization property.