Soft Computing Techniques for Operation and Control of Modern Power System

Abstract

Economic dispatch (ED) is one of the most important problems in power system operation which deals with allocating the total demand to the committed generating units in the most economical manner while all the physical and operational constraints are satisfied. Initially, the cost curves of generating units were assumed to be quadratic in nature, which permitted the use of gradient based conventional optimization methods. Later, many non-linearities and discontinuities were identified in the generator cost characteristics which the traditional methods could not handle. During the last decade, the economic dispatch formulation became more explicit due to the introduction of many constraints which were not included earlier. These constraints convert the ED problem into a, non-linear, nonconvex, discontinuous, multi-modal optimization problem with complex equality and inequality constraints. newlineIn this thesis, valve point loading effects, prohibited operating zones, ramp-rate limits, joint dispatch of energy and reserve, transmission limits, spinning reserve, area-wise power balance and environmental constraints are some of the issues which have been formulated in the optimal generation allocation problem. newlineED has the objective of generation allocation to the power generators in such a manner that the total fuel cost is minimized while all operating constraints are satisfied. For the sake of simplicity, ED is generally solved without accounting for transmission constraints. However, in deregulated power system environment it is essential to model the ED problem for practical multi-area cases with tie-line constraints. Most of the conventional gradient based methods are time consuming, suffer from dimensionality problem and assume the fuel cost curves of generating units to be piecewise linear, monotonically increasing in nature.