摘要
笔者探讨了一起110 kV交叉互联电缆外护套及主绝缘烧损击穿事故的原因,计算和仿真了电缆在两种极端情况下金属护套的悬浮电位和电缆胶皮外护套悬浮电位之间的电位差,并根据事故电缆的实际状况给出了故障起因。结果表明:电缆金属护套只要形成中性点连接,即使在不接地的情况下其悬浮电位依然很低;在电缆金属护套和胶皮外护套石墨层均不接地的情况下,金属护套和石墨层悬浮电位接近运行电压,但此时电缆胶皮外护套承担的电压差仅几百伏,此种情况不会对电缆运行造成危害;文中分析过程为进一步深入理解电缆故障起因提供了新认识。
A breakdown failure of outer sheath and main insulation of a 110 kV cross-connected cable is analyzed.The difference of floating potentials on the metal sheath and the outer sheath are computed and simulated in two extreme conditions, and the cause of the failure is obtained. Results show that the floating potential of the cable metal sheath is very low even in unearthed condition as long as neutral point connection forms. For unearthed metal sheath and graphite layer of outer sheath, their floating potentials are close to the operating voltage, however the voltage on the outer sheath is safe for the cable＇s operation.
出处
《高压电器》
CAS
CSCD
北大核心
2014年第9期47-52,共6页
High Voltage Apparatus
关键词
高压电缆
绝缘故障
金属护套
悬浮电位
击穿
high voltage cable
insulation fault
metal sheath
floating potential
breakdown
