Self-organized criticality characteristics of unplanned power failures in distribution network

This paper studied the SOC characteristics of the unplanned power failures in distribution network. In order to discover the SOC characteristics of the power failures, the statistical data of reliability in one middle-size city in China are presented firstly. The total interruption duration of customers and total interruption duration of system of unplanned power failures are considered as the variables. Secondly, linear fittings between the scales and frequencies of the variables are performed on the double-log coordinates with the least squares method respectively. F test method is applied to validate the linear relationships. The linear fitting results show that there are the power-law distribution relationship between the scale and frequency of the variables which testify the SOC characteristic of the unplanned power failures in distribution network just like the blackouts in the transmission system. Finally, some distribution network operation guidance are given according to the SOC characteristics. The SOC characteristics can provide analytical tools and theoretical basis for the improvement of the distribution network operation, the assessment and forecasting of reliability.