Observer-based decentralized control of inter-area oscillation in Multi-infeed HVDC system

An important concern in the operation of multi-infeed HVDC systems is the inter-area low frequency oscillation due to the long-distance bulk-power transmission. In this paper, a decentralized coordinated control design is presented for improvement of inter-area oscillations in the multi-infeed HVDC system. The DC modulation controller are designed based on LQR optimal method and decentralized observers. Without degradation of controller performance, only the local measurement output is required for each damping controller, which greatly reduces the communication burden. A 7-generator, 2-HVDC system was used as the test system. The eigenvalue analysis and nonlinear time domain simulation have demonstrated the validity of the proposed decentralized controllers.