Wu Zhi-Yuan, Jin Yu-Zhi, Shi Zhe-Xu, Wang Zhi-Yuan, Wang Wei
School of Electrical and Electronic Engineering, North China Electric Power University, Beijing 102206, China.
Northwest Branch of State Grid Corporation of China, Xi'an 710199, China.
Polymers (Basel). 2024 Aug 20;16(16):2356. doi: 10.3390/polym16162356.
The insulation of high-voltage direct-current (HVDC) cables experiences a short period of voltage polarity reversal when the power flow is adjusted, leading to sever field distortion in this situation. Consequently, improving the insulation performance of the composite insulation structure in these cables has become an urgent challenge. In this paper, SiC-SR (silicone rubber) and TiO-SR nanocomposites were chosen for fabricating HVDC cable accessories. These nanocomposites were prepared using the solution blending method, and an electro-acoustic pulse (PEA) space charge test platform was established to explore the electron transfer mechanism. The space charge characteristics and field strength distribution of a double-layer dielectric composed of cross-linked polyethylene (XLPE) and nano-composite SR at different concentrations were studied during voltage polarity reversal. Additionally, a self-built breakdown platform for flake samples was established to explore the effect of the nanoparticle doping concentration on the breakdown field strength of double-layer composite media under polarity reversal. Therefore, a correlation was established between the micro electron transfer process and the macro electrical properties of polymers (XLPE/SR). The results show that optimal concentrations of nano-SiC and TiO particles introduce deep traps in the SR matrix, significantly inhibiting charge accumulation and electric field distortion at the interface, thereby effectively improving the dielectric strength of the double-layer polymers (XLPE/SR).
高压直流（HVDC）电缆的绝缘在调整功率流时会经历短时间的电压极性反转，从而在这种情况下导致严重的电场畸变。因此，提高此类电缆复合绝缘结构的绝缘性能已成为一项紧迫的挑战。本文选用碳化硅 - 硅橡胶（SiC - SR）和二氧化钛 - 硅橡胶（TiO - SR）纳米复合材料来制造高压直流电缆附件。这些纳米复合材料采用溶液共混法制备，并搭建了电声脉冲（PEA）空间电荷测试平台来探究电子转移机制。研究了在电压极性反转过程中，由交联聚乙烯（XLPE）和不同浓度纳米复合硅橡胶组成的双层电介质的空间电荷特性和场强分布。此外，搭建了一个自制的片状样品击穿平台，以探究纳米粒子掺杂浓度对极性反转下双层复合介质击穿场强的影响。因此，建立了微观电子转移过程与聚合物（XLPE/SR）宏观电学性能之间的关联。结果表明，纳米碳化硅和二氧化钛颗粒的最佳浓度在硅橡胶基体中引入了深陷阱，显著抑制了界面处的电荷积累和电场畸变，从而有效提高了双层聚合物（XLPE/SR）的介电强度。
