中文摘要：

在建立基于IEC61850全数字化保护系统的马尔科夫模型时．主要困难是由于其结构的复杂性而导致的状态空间爆炸问题。为此，介绍了全数字化保护系统的典型结构，根据其功能与结构特点．提出了分层马尔科夫模型和一种状态空间简化方法。该方法将描述系统层的状态提炼到顶层马尔科夫模型中．并根据马尔科夫状态的概率，去除数目巨大但又概率极低的状态。基于该模型导出了一套基于IEC61850的全保护系统的总体可靠性指标。最后以一次系统采用3／2接线的全数字化保护系统为例给出详细的仿真计算结果。结果表明．所提出的马尔科夫状态空间简化方法不仅有效解决了全数字化保护系统状态空间爆炸问题，保留了很高的计算精度．而且适用于各种结构的全数字化保护系统。

英文摘要：

It is difficult to establish the Markov model of IEC61850-compliant protection system due to the complexity of its architecture,which causes the state space explosion. The typical architecture of an IEC61850-compliant protection system is introduced. According to its functional and structural features,a layered Markov model and a simplification method of state space are proposed,which abstracts the states of representation system layer into Markov model by eliminating a large amount of ＂rare＂ states according to the probability of Markov states. The overall reliability index of IEC61850-compliant protection system is derived based on the model. With an IEC61850-compliant protection system as an example,the primary system of which applies 3/2 wiring mode,the detailed simulative results demonstrate that,the proposed method avoids the problem of state space explosion, has a high calculation accuracy and is suitable for the IEC61850-compliant protection systems with different structures.