数字化变电站的分布式联锁功能安全性研究

针对现有定性评价分布式联锁功能安全性方法的不足,应用马尔科夫模型理论,提出了定量分析数字化变电站分布式联锁功能安全性的方法。研究了分布式联锁功能的实现过程;分析了联锁信息的传输特性,建立了导致联锁信息传输时延不确定的永久失效和瞬时失效模型,以及联锁信息的重传和延迟模型;引入安全综合等级,根据分布式联锁功能的工作特点,应用马尔科夫模型理论,综合考虑了永久失效和瞬时失效模式,建立了评价分布式联锁功能安全性的马尔科夫模型,推导出了求解功能安全综合等级的解析表达式。并以一实际分布式联锁功能为例,得到了联锁功能的状态概率和安全性指标,以及合理的联锁信息传输方案可提高联锁功能安全性等结论。

Safety of distributed interlock function in digital substation

Based on Markov model theory,a quantitative analysis method is proposed to assess the safety of distributed interlock function of digital substation as a supplement to the qualitative methods.The implementation process of the distributed interlock function and the transmission characteristic of the interlock information are analyzed.The models of permanent and instantaneous failures,which bring the indeterminable delay in interlock information transmission,and the models of repeating interlock information transmission and delay are set up.Based on these models,a model using SIL(Safety Integrity Level) to assess the distributed interlock function is established and its analytic expression is deduced.The state probability and SIL of a case are calculated as an example,showing that the rational transmission scheme of interlock information can improve its safety.