计及微振磨损与风雨荷载的输电线可靠性建模

Reliability modeling for transmission lines incorporating fretting under strong wind and rain loads

输电线长期受风导致的振动引起股线间微振磨损,而外部强风雨荷载的冲击进一步加剧了磨损程度,导致断股、断线事故风险显著增加,因此对经受长期微振磨损的输电线在强风雨荷载冲击下的可靠性模型进行研究具有重要实用价值。基于微振磨损的理论模型建立了ACSR的结构强度时变模型,在考虑微振磨损的基础上计入强风雨荷载的影响,结合输电线强度和永久荷载的随机特性,建立输电线时间相依可靠性模型。所提时间相依故障概率模型可以对输电线断股、断线风险进行准确预测并实现恶劣天气下的输电线风险预警。算例结果表明,微振磨损会显著降低输电线的结构可靠性,而强风雨条件下的雨荷载则进一步加剧了事故风险。

The fretting between wires of transmission lines caused by long-term wind-induced vibration results in rupture of wires easily. The impact of strong wind and rain loads exacerbates the risk, which results in a significant increase in broken strand and broken lines. It’s necessary to study reliability modeling of transmission lines which bears long-term fretting under the impact of strong wind and rain loads. According to theoretical models of fretting, the time-varying structural strength model of aluminium conductor steel reinforced （ACSR） is built up, the contact stress between wires is solved. Thereby the time-varying model of structural resistance is built up. According to the joint action of fretting and strong wind and rain loads, the random nature of transmission line strength and permanent load, the time-dependent reliability model of transmission lines are built up. Numerical results show that fretting degrades reliability model and rain load can’t be neglected under strong wind and rain condition. Time-dependent failure probability model can be used to perfect forecast the rupture risk of wires and make risk warning under inclement weather. The example results prove that fretting will reduce the structural reliability of the transmission line significantly and the strong wind and rain loads increase the risk of the accident.