A Mixed Integer-Linear Programming Model for Solving the Hydroelectric Unit Maintenance Scheduling Problem

This paper presents an optimization modeling approach utilizing Mixed Integer Linear Programming (MILP) techniques to address the hydroelectric unit maintenance scheduling problem for British Columbia Hydro and Power Authority (BC Hydro) systems. The research leverages specialized linear formulations and algorithms to solve the combinatorial maintenance problem in large-scale hydroelectric systems. The primary objective is to determine the optimal timing and sequencing for each unit outage within the system, ensuring system productivity, reliability, and operability. The proposed method involves a detailed MILP formulation that considers various constraints. A novel ‘maintenance shape’ algorithm is designed to handle the nonlinearity arising from the maintenance continuity preference, ensuring that all units' maintenance activities within each plant are arranged sequentially without breaks. Results from the case study illustrate the systematic effects of unit maintenance on BC Hydro's competitiveness in the electricity market. The model can be extended to include more plants and reservoirs, providing a valuable tool for BC Hydro and similar utilities in strategically managing their maintenance operations. © 2025 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.