A novel transient based protection for /spl plusmn/800 kV UHVDC transmission lines

A novel transient based protection for /spl plusmn/800 kV UHVDC transmission lines is proposed in the paper. A /spl plusmn/800 kV UHVDC bipolar model with DC control system is built with PSCAD/EMTDC software. Wavelet-multiresolution signal decomposition technique is applied to analyze the transient voltages. Based on spectral energy distribution of transient voltages, the criteria are presented to distinguish the UHVDC line faults from other transient phenomena. Extensive simulations are used to test the criteria. The results show the proposed transient based protection is highspeed, reliable and suitable for UHVDC lines.