Research On Power System Optimal Power Flow With Considering Unified Power Flow Controller

Flexible AC Transmission System (FACTS) provide a real-time, accurate andflexible power flow control to AC grid.Unified power flow controller (unified power flowcontroller, UPFC) as one of the most representative FACTS controller has both shuntcompensation, series compensation and phase-shift function, since its concept, it has beensubject to the attention of scholars from various countries. The study contains unifiedpower flow controller power system optimal power flow problem has importantimplications for modern smart grid.Firstly the optimal power flow problems with unified power flow controller arereviewed and summarized in this paper, then analyzed the working principle andequivalent circuit model of unified power flow controller, on this basis, according tonetwork-equivalent, the steady-state model of unified power flow controller in power gridanalysis is established.According to steady-state model, the grid optimization model which containsunified power flow controller is established, and proposes a new algorithm to solve theoptimal power flow problem with unified power flow controller, which is calleddecomposition algorithm. In this algorithm, the optimal power flow calculation problem ofelectric power system which contains unified power flow controller is decomposed intoinside and outside two layer alternate solution: the outer layer is based on Tabu search,achieves the optimization of unified power flow controller active power setting value bycalling the inner optimization calculation; the inner optimization calculation which is underthe conditions of determined unified power flow controller active power setting value,using existing numerical optimal power flow calculation method calculates equivalentselectricity network optimization in order to determine unified power flow controllerreactive power, voltage setting value and optimal power generation mode. According to thecalculated optimal control target setting value of unified power flow controller and theoperation of the system state, the optimal control parameters of the unified power flow controller can be obtained. Finally, write programs to verify the effectiveness of thealgorithm in3-node system and IEEE-30node system.On the basis of the study on unified power flow controller, the working principlesand equivalent circuit of multi-terminal unified power flow controller (multi-terminalunified power flow controller, M-UPFC) is discussed and the steady-state model ofmulti-terminal unified power flow controller in power grid analysis is established. On thisbasis, the new decomposition algorithm is applied to solving the optimal power flowproblem containing the multi-terminal unified power flow controller; also write programson IEEE-30node example calculation and analysis to verify the effectiveness of thedecomposition algorithm.