Abstract：This article analyzes the 0.6Hz low frequency oscillation phenomenon in the on-site AC system of the Matiari-Lahore high voltage direct current (HVDC) project. The AC equivalent network is used to simulate the actual oscillation of AC system, and the two strategies of frequency control and bilateral frequency difference control are simulated and analyzed in real time digital simulation (RTDS). It is found that when the AC system is subjected to large disturbance and produces low frequency oscillation, the frequency limiting function can not play a good damping effect and the oscillation amplitude becomes larger and larger. Bilateral frequency difference modulation can produce a certain positive damping, then the low frequency oscillation is restrained, the oscillation amplitude gradually weakens. Therefore, adding bilateral frequency difference control to suppress low frequency oscillation in the project is suggested.
2023, Vol. 24 
