Selection of water delivery schedule based on peak-valley electricity price and annual cost usage

The rational water delivery schedule is an important way to reduce water engineering cost, and the appropriate comparative method is the premise of optimization schedule. Currently, water delivery schedule selection is mainly based on the initial investment cost comparison. It is simple, but did not consider the value of the power cost of pipe network, peak-valley electricity price and the other factors. With the rise of electricity prices, power cost is a growing proportion in the total costs. As peak-valley electricity price carrying out, transmitting water in the time of the lower electrovalency can reduce power cost, but water pipeline and storage structure put forward new requirements. The cost for the filling and emptying system optimization will be between capital cost and power cost optimization. Therefore, this paper presents the annual cost method based on peak-valley electricity price as a new method of comparison, considering the initial capital investment costs, the power cost during the network operation, depreciation and overhaul costs and the other factors. This paper presents three water delivery schedules: 1) transmitting water uniformly in 24 hours by two parallel pipes; 2) transmitting water uniformly in 24 hours by one pipe with a reservoir in the end; 3) transmitting water uniformly in the time of lower electrovalency by one pipe with a reservoir in the end. Using the minimum annual cost of the water delivery as the objective function, and the reliability of water delivery system as the constraint condition, we find out the minimum annual cost of the three water delivery schedules. The results of power costs have a large proportion in annual cost, the price of electricity has an important effect on the water transmission selection. As peak-valley electricity price carrying out, rational water transmitting in time of lower electrovalency can reduce power cost.