Wind-Hydro Combined Bidding Approach for Congestion Management Under Secured Bilateral Transactions in Hybrid Power System

After restructuring of power system, independent system operator is facing a big challenge to manage operations on transmission networks due to growing renewables share and involvement of large market players in power system operation. Among all renewables, wind power has the most stochastic nature and faces penalties due to mismatch in its initial power committed and final power delivered. Also, wind power plants are generally located at remote areas and need longer transmission lines for power delivery. This leads to congestion of transmission lines and poses a threat to security and safety of power system. To manage congestion on transmission lines, this paper proposes a novel rescheduling based combined bidding approach for wind integrated hybrid (pool + bilateral) power system. Congestion management problem has been formulated as mixed integer non-linear programming problem incorporating proposed combined bidding approach with an objective to reduce total congestion management cost through rescheduling of wind and hydro units on the basis of their combined up and down generation cost bids. The hydro units that have lowest operating cost and fast turn-on time have been used in coordination with wind units to alleviate congestion cost. Secured bilateral transactions have been confirmed while implementing the combined bidding approach for congestion management. Performance of proposed strategy has been analyzed by demonstrating it on modified IEEE-24 bus RTS system.