Real-time(RT)simulation of active distribution networks(ADNs)is an effective method for studying the dynamic behaviors of the real system

simulating the real operation environment and testing the protecting control strategies. A multiple field programmable gate array(FPGA)based RT simulator with multi-level parallel architecture for ADNs is designed

which takes advantage of the massive parallelism

deep pipeline

and rich distributed memories of FPGA. In order to satisfy the expandability of the RT simulator

the ADN is firstly decoupled into subsystems by using the physical decoupling method

i. e. coarse-grained partition. Then each subsystem is split into segments according to the components type

i. e. fine-grained partition. Finally

these segments are mapped into the corresponding FPGA hardware resources. The 4-level parallel simulation architecture of system-level

unit-level

module-level and element-level is constructed by the hardware resource distribution and coordination mechanism. RT simulation of a typical active distribution network including photovoltaic(PV)generation units and energy storage units is achieved on a 4-FPGA based simulator. Simulation results are compared with those of PSCAD/EMTDC to validate the correctness and effectiveness of the multi-level parallel architecture design.