The distribution static synchronous compensator is normally selected to compensate for reactive current and negative sequence current when unbalanced load is connected into grid.Compared with PI control system normally used by static synchronous compensator

a proportional resonance（PR）control system based on the instantaneous symmetry component method and the signal delay cancellation method（DSC）is proposed in this paper.Firstly

the positive and negative-sequence components of the grid current are separated by DSC method.Then

the positive and negative sequences components are controlled separately at αβ two-phase stationary coordinates to keep the DSTATCOM compensate the reactive current and the negative sequence current.The proposed control strategy

compared to PI control system

simplifies the calculation

improves the steady and dynamic performance of the system.Finally

the DSTATCOM experimental platform of low voltage distribution grid is set up.It is shown by the experimental result that the PR control method proposed can achieve to compensate reactive power current and negative sequence current.The power grid is close to unity power factor

the grid current THD is less than 5% and the degree of balance meets the China national standard.