A Whole-Line Quick-Action Protection Scheme for Distribution Lines Based on Single-End Electrical Parameters

Independent of power supply property, single-ended quick-action protection, only related to line topology, is an important scheme to improve weak protection configuration of present distribution networks. This paper designs a type of boundary elements, namely the capacitors in parallel to bus, playing role of a compensation element at steady state and fault identification device during transient fault period. A method of whole-line quick-action protection for distribution lines is proposed based on single-end transient voltage energy extracted with wavelet decompositions associated with instantaneous currents. PSCAD simulation results prove that the method can quickly and reliably distinguish internal and external phase-to-phase faults in distribution lines with strong ability of enduring fault resistance. Meanwhile, the larger the boundary capacitance is, the more conducive will be to distinguish the faults, but its volume selection still depends on system operation requirements, and economic and other factors.