1. Department of Electrical Engineering, Tsinghua University, Beijing 100084, China; 2. Electric Power Research Institute of State Grid Sichuan Electric Power Company, Chengdu 610072, China

With the integration of distributed generators and other complex devices, analyses of the transient state process for distribution systems and electromagnetic simulation are gradually becoming dependent on detailed modeling and electromagnetic transient(EMT)simulation. As EMT simulation can be appreciably accelerated by fine-grained parallel devices, such as the graphics processing unit(GPU). GPU-based parallel electromagnetic transient simulation techniques for large-scale distribution system are proposed. First, the computational models are formulated by categorizing the overall computations during simulation into three parts, that is, heterogeneous, homogeneous and network solution part. Then, each part of computation is accelerated using fine-grained parallel strategy on the GPU. The heterogeneous part is processed in a layered-directed-acyclic-graph based kernel, the homogeneous part is handled in a fused multiply-add kernel, and the network solution part is done by linear algebraic solvers on the GPU. Finally, large-scale cases are provided for tests. Simulation results indicate that the proposed techniques can significantly accelerate EMT simulation for distribution networks.