Abstract:

The risk index can integrate the possibility and severity of accident， and can be used to predict the sequence of cascading failure in power grid. The possibility index in traditional risk assessment only considered the line failure rate， but the line overload outage was one of the important reasons of cascading failure in power grid. In order to consider the complex uncertainty in power grid， according to the line fault， protection actions caused by line irregular working， environmental factors and human errors， the integrated outage rate of each line was determined. Taking the integrated outage rate of line as the possibility index of cascading failure， the cascading failure risk assessment model was further established for power grid considering line outage rate， combining with the severity index. The WSCC-9 buses system and a local power grid were simulated by using the proposed method， whose results proved that the method was correct， objective， and had certain engineering application value.

Key words: cascading failure, possibility, line outage rate, risk assessment