A Practical Approach for Large Scale Optimal Pump Scheduling with Operational Constraints

A Practical Approach for Large Scale Optimal Pump Scheduling with Operational Constraints

 

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Abstract:

Energy costs, and in specific, energy used by pumps to extract water and to deliver it, comprises the largest component of the operational costs of most water distribution systems. It is therefore much desired to optimize the operation of water distribution systems through the scheduling of pumps and other elements, to take advantage of time-varying energy tariffs and minimize energy costs.

 

However, mainly due to the non-linear nature of the system and to the complexity of operational constraints involved, optimizing the operation of large and interconnected water distribution systems, with operational constraints, usually results in highly nonlinear or mixed integer optimization problems, which are impractical for large setups, especially where near real time operation is required.

We propose an approach to solve the problem, involving a simple iterative heuristic and a linear programming model. The linear model solves the problem without some of the operational constraints, while the heuristic sets operational constraints iteratively and resolves infeasibilities caused by previous steps.

 

The approach is demonstrated and evaluated on a practical setup. We show that the method proposed achieves close to optimal results, at reasonable computation resources. An extension for the case of more complex cost structure, involving multiple electricity suppliers with aggregative costs is also presented. This extension can be used for optimizing water distribution systems at the national level.