Optimization of Economic Dispatch of 150 kV Sulselrabar System using Lagrange Approach

In this study, the Lagrange method was used to solve the Economic Dispatch problem in the 150 kV electrical system in South, Southeast and West Sulawesi (Sulselrabar). The South Sulawesi system consists of several thermal and non thermal plants. For this reason, arrangements are needed to regulate the loading of the power plant, so that the amount of electricity generated in accordance with the needs and production costs is to a minimum. This research will propose the Lagrange method to find an economical composition of plants. The case study used was the peak daytime load. In this economic dispatch, the algorithm will work based on the given objective function, the objective function is the cheapest generation cost. From the optimization results of generation for the case of peak daytime load, using the Lagrange method, it was obtaining the total generation cost is IDR. 117,121,631.08/hour to generate power of 339.4 MW with losses of 25.016 MW. While in the real system the total generation cost is IDR. 127, 881, 773.68/hour to generate power of 393.1 MW with losses of 24.956 MW. The Lagrange method can reduce the Sulselrabar system generation costs by IDR. 10,760,142.6/hour or 8.41% in peak daytime loads.