Congestion management considering hydro–thermal combined operation in a pool based electricity market

This paper proposes a novel congestion management strategy for a pool based electricity market considering combined operation of hydro and thermal generator companies. The proposed congestion management problem is formulated as mixed binary nonlinear programming problem to minimize the cost of re-dispatching the hydro and thermal generator companies to alleviate congestion subject to operational, line overloading and water availability constraints. A piecewise-linearized unit performance curve is used in this formulation, which takes into account its non-concave nature. The effectiveness of the proposed technique is demonstrated by solving the modified IEEE 57-bus and IEEE 118-bus systems for congestion management under line outages.

► The novelty of the paper is modeling of hydro units in the congestion management problem formulation.
► Congestion management cost decreases with hydro units’ participation.
► An ac Optimal Power Flow (OPF) based modeling of power system is considered.
► The ac modeling follows MVA line loading and bus voltage limits after congestion management.