Bordered-Block Diagonal Form For Parallel Electromagnetic Transient Simulation

This paper presents and compares two delay-free methods to parallelize Electromagnetic Transient (EMT) simulations when there is no line propagation delay for decoupling. Both methods involve transforming the network matrix into a Bordered-Block Diagonal form, allowing for parallel decoupling. In the first one, BBD (node tearing), the BBD form is obtained with no variable addition. In the second method, the Compensation Method (CM), additional variables, such as compensation currents, are required to achieve a parallelizable BBD form. Graph partitioning techniques (Metis) are used to automate the network decoupling in both methods, which are implemented in a Julia-EMT code. Each BBD-based method achieves substantial performance gains on practical networks.