Keerati Chayakulkheeree2555-08-052555-08-052555-08-05https://dspace.spu.ac.th/handle/123456789/3783This paper proposes a fuzzy constrained optimal power flow (FCOPF) algorithm with non-linear fuzzy network and generator ramprate limit constraints. The problem is decomposed into total fuel cost fuzzy minimization subproblem and total real power loss fuzzy minimization subproblem, which are solved by fuzzy linear programming (FLP). In the total fuel cost fuzzy minimization subproblem, the line flow and transformer loading limits and the generator ramprate limits are treated as fuzzy constraints. Whereas, in the total real power loss fuzzy minimization subproblem, the bus voltage magnitude limits are treated as fuzzy constraints. The non-linear S-shape membership function is used for representing soft characteristic of fuzzy constraints. The proposed FCOPF algorithm is tested on the IEEE 30 bus test system with and without lines outage cases. The results show that the fuzzy constrained optimal power flow algorithm can successfully trade off among total fuel cost, line flow and transformer loading and generator ramprate in the total fuel cost fuzzy minimization subproblem and between total real power loss and bus voltage magnitude in the total real power loss fuzzy minimization subproblem.otheroptimal power flowfuzzy linear programmingArticle