【摘要】 以实际直流交联聚乙烯(DC XLPE)电缆工程设计示例,表明将柔性直流输电(VSC)系统用DC XLPE电缆的导体的最高运行温度提高到90℃,其技术经济效果显著。按DC XLPE电缆抑制空间电荷要求,阐明DC XLPE电缆绝缘的直流恒定电流电场中空间电荷密度与绝缘温度梯度和XLPE绝缘的体积电阻率的温度系数成正比而与导体最高温度不直接相关。通过合理的DC XLPE电缆工程设计和正确选用DC XLPE电缆,可以在提高DC XLPE电缆传输功率和减小绝缘温差抑制空间电荷方面取得优化结果。320 kV及以下XLPE电缆在导体最高温度90℃下运行,绝缘损耗远低于导体损耗,DC XLPE电缆发生热不稳定的可能性很低。对VSC系统用DC XLPE电缆导体运行温度提高到90℃的可行性表示肯定的意见,对实现目标提出具体的措施建议。更多还原

【Abstract】 The significant techno-economic effect by raising the maximum conductor temperature of DC XLPE cable to 90℃ for VSC system is confirmed with example of DC XLPE cable engineering design as shown in the paper. The paper illustrates that space charge density is proportional to the temperature coefficient of resistivity as well as temperature gradient in DC XLPE insulation rather than relating directly the maximum conductor temperature of DC XLPE cable. It is possible to optimize DC XLPE cable property aiming at higher transmission power and less space charge accumulation for DC XLPE cable operated at maximum conductor temperature of 90℃. Besides the paper indicates that insulation loss caused by leakage current of DC XLPE cable with rated voltage up to 320 kV is much lower than conductor current transmission loss at 90℃. Very low possibility of thermal instability for DC cable insulation is expected. It is concluded that raising the maximum temperature of DC XLPE cable to 90℃ is feasible and some concrete measures are proposed to realize the target.更多还原