Improved Adaptive Current I Segment Protection of Smart Converter Substation

In the distributed power access distribution network, the short circuit current dynamically changes with the difference of accessed capacity and position, resulting in insufficient sensitivity or even refusal of the traditional three-stage current protection based on the maximum operation mode setting. Adaptive current protection in the distribution network needs to be studied. Based on the analysis of the influence of distributed power supply distribution network on current protection, the composite fault network is constructed when the system occurs in the upstream, downstream or adjacent feeders of the distributed power supply. Further, the positive sequence voltage and the positive sequence current at the time of the fault are used to calculate the current at the end of the line in real time, and based on this, the current value of the over-current protection I segment is set. Finally, it is verified that the protection method can set the current value and improve the protection performance based on the PSCAD simulation.