Three-level Control Scheme For Load-frequency Control Of Interconnected Power Systems

This paper presents a decentralized control technique for the Load-Frequency Control (LFC) of a single area multimachine power system. This technique is evolved from a three-level hierarchical scheme which successfully converts the LFC problem into an interactive proess. The decentralized computation is carried out both horizontally by generating a group of local decoupled optimization subproblems, and vertically through the division of the coordination task into two nested optimization processes. The former ensures that the optimal local subproblems are satisfied and hence, yields the local optimum solutions. The latter takes into account system nonlinearities and interconnections art d ensures that the performance of the overall system is optimized. This paper differs from previous works in that the proposed technique is fast and simple, and permits optimality at all the levels while providing a decomposed solution. Moreover, the proposed scheme guarantees practically zero steady-state error in both frequency and tie-line power at the final time.