WAMS based robust HVDC control considering model imprecision for AC/DC power systems using sliding mode control

This paper presents a wide-area measurement based robust controller (WMRC) design method for high-voltage direct-current (HVDC) links to enhance the stability of AC/DC power systems. In recent years, there has been considerable interest in designing HVDC controllers to enhance system stability; however, model imprecision of HVDC systems has not been fully studied. The proposed WMRC utilizes sliding mode control to cope with the model imprecision of a conventional reduced first-order HVDC model and selects the area center of inertia (COI) signals as the feedback signals. The steps of the control design are as follows: firstly, the dynamics of the COI are established based on the motion equations of the generators; secondly, the sliding mode control manages to control the COI dynamics in spite of the model imprecision of the HVDC system, and the Lyapunov stability theory is applied to ensure that the system is asymptotically stable; thirdly, the applicability of the WMRC in AC/DC power systems is verified by real system detail tests. The superiority of the WMRC is verified in a 2-area 4-machine AC/DC power system and a real large-scale AC/DC power system.

► We develop a robust controller for HVDC links to enhance the system ability.
► The proposed controller takes model imprecision of HVDC systems into consideration.
► The area center of inertia signals are selected as the feedback signals.
► The proposed controller can be applied to power systems with multiple HVDC links.
► Simulation results demonstrate the effectiveness of the proposed controller.