The Harmonic Stability Analysis of HVDC System Based on Short-Circuit Ratio

According to harmonic stability problem that was caused by the non-linear of converter, the simulation model was established based on the actual equipment situation of convert station, and the circuit of system was simplified through the Thevenin Theorem. The main influence factor of harmonic instability was analyzed by watching the change of the system short-circuit ratio in the simplified circuit. Finally, some important conclusions have been obtained that the ratio of second harmonic of AC-side plays a leading role to the possible existence harmonic instability of HVDC system.