Wide-area Signal-based Optimal Neurocontroller for a UPFC


The design and implementation of an optimal neurocontroller for a flexible ac transmission device—the unified power-flow controller (UPFC)—is presented in this paper. Wide area signals in a power system are used to provide auxiliary control to a UPFC in order to achieve enhanced damping of system oscillations. The neurocontroller provides auxiliary signals to the real and reactive power references of a UPFC series inverter. The design of the optimal neurocontroller is based on an adaptive critic design approach—the heuristic dynamic programming. A system identifier, referred to as the wide-area monitor), and a critic network (performance evaluator) are designed for optimizing the neurocontroller. Real-time implementation of the optimal UPFC neurocontroller for a multimachine power system is carried out successfully on a digital signal processor. The power system is simulated on a real-time digital simulator. The performance of this neurocontroller is compared with a conventional linear damping controller. Results show enhanced damping of both inter-area and intra-area modes in the power system under different operating conditions and disturbances with the neurocontroller. The improvement in the damping is also quantified using the Prony method.


Electrical and Computer Engineering

Keywords and Phrases

Flexible Ac Transmission Systems (FACTS) Device; Heuristic Dynamic Programming (HDP); Optimal Neurocontroller; Prony Analysis; Unified Power-Flow Controller (UPFC); Wide-Area Control; Wide-Area Monitor (WAM)

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Document Type

Article - Journal

Document Version


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© 2008 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jul 2008