The composition and principle of the improved host injection test platform for fault handling performance test of power distribution network with distributed generators(DGs)is described. The power flow calculation method and short circuit current calculation for the power distribution network with DGs are discussed. A natural fault scenario set-up approach is put forward. The action of relay protections

automatic devices

feeder terminal units(FTUs)and circuit breakers are simulated according to the comparison of short circuit calculation and the setting values. In addition

the action of switches and DGs separate from the grid during the restoration procedure can also be simulated. Thus

the correctness of the scheme and steps of service restoration can be tested more effectively. Examples are given to illustrate the feasibility and effectiveness of the test technology proposed.