The increasingly frequent happening of extreme natural disasters has led to large-scale outages with tremendous economic losses. The capability of the distribution system to endure disasters has been widely discussed as a result. To assess this capability

the concept of resilience is introduced. This paper reviews related investigations in the engineering resilience area and their applications to distribution systems. The concept and inner meaning of resilience are firstly introduced

and its significance in distribution systems is demonstrated by comparisons with reliability and cascading failures in transmission systems. Next

the assessment matrix is introduced

followed by quantitative indices

which are useful for planning and operation of distribution systems. Measures to enhance distribution system resilience are also put forward. Finally

key problems and possible research directions in the resilience research area are proposed. This work is supported by Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No. 51321005)

National Natural Science Foundation of China (No. 51277104

No. 51477081)

and Tsinghua University Initiative Scientific Research Program (No. 2012Z02140).