Abstract
Maintenance scheduling of generating units in restructured power systems is a collaborative and interactive
process between independent system operators (ISOs) and generating companies (GENCOs). The ISO should comply
with GENCO maintenance preferences subject to targeted system reliability levels. This process might be multistage since
the admission of all initial unit outage requests may threaten system reliability. Hence, the ISO accepts some proposals
and determines alternatives for the remaining units. The GENCOs are then allowed to conrm the alternatives or revise
them. In this paper the ISO problem of generating unit maintenance scheduling is tackled. The objective function is
to minimize the deviation of awarded schedule from the requested schedule, as measured in MW weeks. A novel and
eective optimization technique is developed to solve the problem at hand. In the proposed methodology, risk leveling and
dynamic programming optimization algorithms are concurrently utilized to lessen the computation burden and enhance
the solution process. The eectiveness of the proposed method and its applicability to real-life systems are veried by
examining the generation section of the IEEE reliability test system (IEEE-RTS). The performance of the new method
is also compared with that of the individual risk leveling approach.