Protection scheme of flexible MTDC transmission line based on ISSA-BiLSTM

Aiming at the problems of poor ability to withstand transition resistance and low recognition accuracy of multi-terminal flexible DC transmission line protection, a diagnostic model combining an improved sparrow search algorithm (ISSA) and bidirectional long short-term memory network (BiLSTM) is proposed. Based on wavelet transform technology, the characteristics of transmission line faults are extracted as model input to train the model; the original sparrow search algorithm is improved by using Sine chaotic mapping, learning particle swarm algorithm strategy, and introducing Gaussian disturbance term. And ISSA is used to optimize the target hyperparameters of BiLSTM, so that the fault diagnosis accuracy is optimal. Finally, based on the PSCAD/EMTDC simulation platform, a four-terminal flexible DC transmission system model is built. The verification shows that it has high fault identification accuracy, strong resistance to transition resistance, and meets the requirements of reliability and rapidity.