Dynamic Security-Constrained Automatic Generation Control (AGC) of Integrated AC/DC Power Networks

This paper introduces an efficient algorithm to adaptively determine the droop coefficients of generating units in hybrid ac-dc networks. These generating units include conventional synchronous generators and multiterminal high-voltage direct-current (MTDC) converters. The proposed algorithm relies mainly on trajectory sensitivity to reschedule power generation according to the new calculated droop coefficients to ensure and/or system stability margin for set of credible contingencies with different load conditions. The Newton shooting method is used to find the new steady-state values for the systems when load is changed. MTDC converters are modeled in such a way to emulate the inertia behavior of the synchronous generators. This virtual emulation is achieved by providing two additional control layers that link and control the converter powers through inertia constants similar to synchronous generators. Also, an expression for generated powers controlled by the droop coefficients is developed to be utilized in the algorithm. Finally, comprehensive simulation studies on the IEEE 68-bus benchmark system are carried out using PSCAD/EMTDC interfaced with MATLAB to validate the proposed algorithm.