Optimal Reactive Power Control in a Multi-Machine Thermal Power Plant

This paper presents optimal reactive power control methods for allocating required reactive power between the synchronous units in a multi-machine industrial thermal power plant while minimizing reactive power exchange at the connection point to the transmission network. In the paper, three different methods based on i) equal distribution, ii) proportional distribution, and iii) distribution according to active line losses in connection lines between respective generators and busbars, are proposed. For comparison, analysis and verification of the results actual data from one of the industrial power plants in Estonia is used. The results presented indicate the advantages and disadvantages of these methods considering different limitations, e.g. active and reactive power loading capability of the units, busbar voltages and line loadings, in the plant.