All time steps in which the constraints are violated are recorded. After the run the sum is added to the changeover time.
The resulting time used for ranking your solution can be higher than the pure changeover time.
Constraint violations shall be penalized. In real plants, exceeding of design values (such as a specified condenser duty) is possible but commonly related to extra costs. To account for these extra costs, each second of constraint violation is punished with one second of additional changeover time and accordingly one second of product loss.
27 April 2015