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

Abstract

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

Hybrid Multi-Infeed Interaction Factor Calculation Method Considering Voltage Regulation Control Characteristics of Voltage Source Converter

“…The line commutated converter based high voltage direct current (LCC-HVDC) is widely used in large-capacity and long-distance transmission occasions [1,2]. Multi-infeed high voltage direct current system (MIDC) is formed by several LCC-HVDC links with close electrical distance and the receivingend alternating current (AC) power grid.…”