POWER-GENERATION SCHEDULING FOR MULTIAREA HYDROTHERMAL SYSTEMS WITH TIE LINE CONSTRAINTS, CASCADED RESERVOIRS AND UNCERTAIN DATA

This paper proposes a new approach to solve the short-term generation scheduling of large-scale hydro-thermal power systems(GSHT). The objective of GSHT is to minimize the total operation cost of thermal units over the scheduling time horizon. In order to solve the problem within a reasonable time, the problem is decomposed into thermal and hydro subproblems. The coordinator between these subproblems is the system Lagrange multiplier. For the thermal subproblem, in a multi-area power pool, it is necessary to coordinate the area generations for reducing the operation cost without violating tie limits. A probabilistic method is employed in considering load forecasting errors and forced outages of generating units to satisfy system reliability requirements. For the hydro subsystem, network flow concepts axe adopted to coordinate water usage over the entire study time span and the reduced gradient method is used to overcome the linear characteristic of the network flow method in order to obtain the optimal solution. Three case studies for the proposed method axe presented.