多元退化因素下的快速切换开关可靠性分析

Reliability Analysis of Fast Transfer Switch under Multiple Degradation Factors

快速切换开关是实现敏感负荷不间断供电的核心设备,其可靠性是供电系统运行稳定的前提,但其可靠性受触头磨损、分合闸电容老化及机构永磁体退磁等诸多因素影响,且此类电工装备服役周期内可靠性分析具有实验成本高与标准不完善等特点。为准确评估快速切换开关可靠性,提出一种基于各薄弱单元退化参数影响下的快速切换开关可靠度计算方法。首先,结合样机实验数据库进行关键失效器件退化规律研究,确定快速切换开关薄弱单元。基于实测真空灭弧单元触头磨损量与分合闸驱动单元电容容量数据,分别得到计及冲击磨损系数变化的触头动态磨损量及分闸电容参数分布规律。然后,为减少大样本快速切换开关电磁场数值计算时间成本,建立了快速切换开关机械特性神经网络预测模型。最后,通过将抽样所得退化参数数据库引入预测模型中,得到了满足性能指标约束条件下的快速切换开关可靠度。研究结果表明,切换开关可靠性最薄弱环节为驱动单元电解电容与灭弧室触头,分闸时间小于8 ms时,5 000次分合闸后,可靠度为0.768。

Fast transfer switch is the core equipment to realize uninterrupted power supply for sensitive loads. Its reliability is the premise of stable operation of power supply system, but its reliability is affected by many factors such as contact wear, opening and closing capacitor aging and mechanism permanent magnet demagnetization. Moreover, the reliability analysis of this kind of electrical equipment during its service cycle has the characteristics of high experimental cost and imperfect standard. In order to accurately evaluate the reliability of fast transfer switch, a calculation method of reliability of fast transfer switch based on the degradation parameters of weak units is proposed. Firstly, the degradation law of key failed devices is studied combined with the prototype test database to determine the weak unit of fast transfer switch. Based on the measured contact wear data of vacuum arc extinguishing unit and opening capacitance capacity of opening and closing driving unit, the dynamic contact wear and opening capacitance parameter distribution considering the change of impact wear coefficient are obtained respectively. Then, in order to reduce the finite element calculation time cost of large sample fast switching switch, a neural network mechanical characteristic prediction model of fast switching switch is established. Finally, by introducing the sampled degraded parameter database into the prediction model, the reliability analysis of fast switching system under the constraint of performance index is realized. The results show that the weakest link in the reliability of the transfer switch is the electrolytic capacitor of the driving unit and the contact of the arc extinguishing chamber. When the opening time is less than 8 ms, the reliability is 0.768 after 5000 times of opening and closing.