This paper proposes a total supply capability(TSC)model and the solution algorithm for flexible distribution network(FDN). Firstly

FDN is defined as a distribution network

which operates in closed loop with flexible control of power flow when multiple feeders are linked together by a flexible switching station(FSS)composed of electronic switches. Secondly

the model and the solution algorithm of TSC for FDN are proposed

the model based on a new flexible load transfer strategy. Finally

the proposed model and solution algorithm are tested through a typical FDN in different scenarios. The test result is compared with the traditional TSC model

showing that TSC will either increase or remain unchanged when a traditional grid is upgraded to FDN

the reason for which is analyzed. The advantages of FDN seen from the aspect of TSC are as follows. On one hand

the TSC is easier to achieve in the FDN since the load can flexibly be distributed in the system. In contrast

only when the load is distributed in a certain specific way

can the traditional distribution network achieve TSC. On the other hand

the network configuration of FND is more concise than that of traditional distribution network with the same TSC. The proposed method has been applied in the argumentation of the first domestic demonstration project of multi-terminals flexible closed-loop medium-voltage distribution network.