Abstract
Integration of renewable energy sources is important in limiting the continuous environmental
degradation and emissions caused by energy generation from fossil fuels and thus becoming
a better alternative for a large-scale power mix. However, an adequate analysis of the interaction
with the alternating current (AC) network during network disturbance, especially during inter-area
power (IAP) oscillations is needed. Insufficient damping of oscillations can significantly impact the
reliability and effective operation of a whole power system. Therefore, this paper focuses on the
stability of the modified Kundur two-area four-machine (MKTAFM) system. A robust secondary
controller is proposed and implemented on a line commutated converter (LCC)-based multi-terminal
high voltage direct current (MTDC) system. The solution consists of a local generator controller and
the LCC MTDC (LMTDC) system, voltage-dependent current order limiter, and extinction angle
controller. The proposed robust controller is designed for the LMTDC systems to further dampen the
inter-area power oscillations. Three operational scenarios were implemented in this study, which are
the local generator controller and double circuits AC line, local generator controller with LMTDC
controllers, and local generator controller with LMTDC controllers and secondary controller. The
simulation result carried out on PSCAD/EMTDC recorded better damping of the inter-area power
oscillation with LMTDC. A considerable improvement of 100% damping of the IAP oscillations was
observed when a secondary controller was implemented on the LMTDC.