A Single-Ended Protection Principle for LCC-VSC-MTDC System with High Resistance Fault Tolerance

Line-commutated converter-voltage source converter (LCC-VSC) power transmission technology does not have the problem of communication failure very usually. It therefore can support long-distance, long-capacity electric energy. However, factors such as topology, control strategy, and short-circuit capacities make traditional protection principles fully applicable to LCC-VSC hybrid systems. To enhance reliability DC systems, a single-ended principle based on coefficients is proposed produced. First, equivalent circuit system analyzed expression first traveling wave deduced accordingly. Then, concept multi-frequency by analyzing amplitude-frequency, characteristics each element. Finally, LCC-VSCDC model built verify superiority itself. Theoretical analysis experimental verification show that has strong interference resistance.