The optimal allocation of DC circuit breakers is of great significance in improving the reliability of DC distribution network and reducing outage cost. Based on the minimum-cut set

a DC load area division method is proposed

and then an outage cost calculation model considering function failure of power electronic devices is established. As the DC circuit breaker will be cheaper with the development of electronic technology

a DC circuit breaker optimization dynamic programming(DP)considering the changing price of the breaker is proposed

in which the sum of switch investment

operating cost and outage cost is designed as the optimization objective

the number and location combination of DC circuit breaker are designed as the stage and the state of DP. By taking a loop distribution network as an example

the method proposed can divide the DC circuit breaker price into several intervals and get optimal allocation schemes of different intervals.