Sequential component based energy storage grid connected line longitudinal protection

In response to the lack of sensitivity of traditional distance protection and longitudinal differential protection in the charge and discharge state of electrochemical energy storage power station connection lines, a new principle of longitudinal protection based on sequence component analysis is proposed. By constructing a composite sequence network model, the mathematical relationship between positive, negative and zero sequence currents under different short-circuit fault types are derived, and a unified criterion coefficient is defined to eliminate the impact of different charge and discharge states on protection performance. Using the PSCAD simulation platform, the effectiveness of the new principle in various operating conditions was verified. The results show that the coefficient value of the new method is significantly higher than that of the out-of-region fault when the new method fails in the region, the charging state sensitivity is better than that of the traditional method, and it can adapt to weak system scenarios. This provides theoretical support for improving the reliability and rapidity of contact line protection of electrochemical energy storage power stations.